Communication method and communication device

Abstract

The present application relates to a communication method and a communication device. A communication method comprises: when a remote terminal has two or more relay links, determining a primary cell on the basis of a first relay link among the two or more relay links. Another communication method comprises: when a first relay link connection has been established between a remote terminal and a first relay terminal, determining whether to use the first relay terminal as a candidate relay terminal for a second relay link.

Description

Communication method and communication device Technical Field

[0001] The present application relates to the field of communications, and more specifically, to a communication method and a communication device. Background Art

[0002] With the development of wireless communication technology, the 3rd Generation Partnership Project (3GPP) introduced relays. Communication based on relay terminals can extend communication distance and improve communication reliability. Remote terminals and network devices can be connected via relay terminals, such as user equipment (UE) to network (U2N) relays. Multiple relay links may exist between a remote terminal and network devices.

[0003] Summary of the Invention

[0004] An embodiment of the present application provides a communication method, including:

[0005] In the case that the remote terminal has two or more relay links, the primary cell is determined according to the first relay link among the two or more relay links.

[0006] An embodiment of the present application provides a communication method, including:

[0007] The network device sends and receives configuration information, where the configuration information is used to indicate that a cell associated with a first relay link connected to a remote terminal is a primary cell.

[0008] An embodiment of the present application provides a communication method, including:

[0009] In a case where a first relay link connection has been established between a remote terminal and a first relay terminal, it is determined whether to use the first relay terminal as a candidate relay terminal for a second relay link.

[0010] An embodiment of the present application provides a remote terminal, including:

[0011] The processing unit is configured to determine a primary cell according to a first relay link among the two or more relay links when the remote terminal has two or more relay links.

[0012] An embodiment of the present application provides a network device, including:

[0013] A sending unit, configured to send configuration information, wherein the configuration information is used to indicate that the cell associated with the first relay link connected to the remote terminal is the primary cell

[0014] An embodiment of the present application provides a communication device, including:

[0015] The processing unit is configured to determine whether to use the first relay terminal as a candidate relay terminal for a second relay link when a first relay link connection has been established between a remote terminal and the first relay terminal.

[0016] An embodiment of the present application provides a terminal device, comprising: a transceiver, a processor, and a memory. The memory is used to store a computer program, the transceiver is used to communicate with other devices, and the processor is used to call and execute the computer program stored in the memory so that the terminal device executes the above-mentioned communication method.

[0017] An embodiment of the present application provides a network device, comprising: a transceiver, a processor, and a memory. The memory is used to store a computer program, the transceiver is used to communicate with other devices, and the processor is used to call and execute the computer program stored in the memory so that the network device executes the above-mentioned communication method.

[0018] An embodiment of the present application provides a communication device, comprising: a transceiver, a processor, and a memory. The memory is used to store a computer program, the transceiver is used to communicate with other devices, and the processor is used to call and execute the computer program stored in the memory so that the communication device performs the above-mentioned communication method.

[0019] An embodiment of the present application provides a chip for implementing the above-mentioned communication method.

[0020] Specifically, the chip includes: a processor, which is used to call and run a computer program from a memory, so that a device equipped with the chip executes the above-mentioned communication method.

[0021] An embodiment of the present application provides a computer-readable storage medium for storing a computer program, which, when executed by a device, enables the device to execute the above-mentioned communication method.

[0022] An embodiment of the present application provides a computer program product, including computer program instructions, which enable a computer to execute the above-mentioned communication method.

[0023] An embodiment of the present application provides a computer program, which, when executed on a computer, enables the computer to execute the above-mentioned communication method. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a schematic diagram of an application scenario according to an embodiment of the present application.

[0025] FIG2A and FIG2B are schematic diagrams of two transmission modes of 3GPP.

[0026] Figures 3 and 4 are schematic diagrams of the user plane protocol stack of the L2 relay UE based on the sidelink in the NR system.

[0027] FIG5 is a schematic diagram of a control plane protocol stack for multipath relay.

[0028] FIG6 is a schematic diagram of relay link failure processing.

[0029] FIG7 is a schematic flowchart of a communication method according to an embodiment of the present application.

[0030] FIG8 is a schematic flowchart of a communication method according to another embodiment of the present application.

[0031] FIG9 is a schematic flowchart of a communication method according to an embodiment of the present application.

[0032] FIG10 is a schematic flowchart of a communication method according to another embodiment of the present application.

[0033] FIG11 is a schematic flowchart of a communication method according to an embodiment of the present application.

[0034] FIG12 is a schematic flowchart of a communication method according to another embodiment of the present application.

[0035] FIG13 is a schematic flowchart of a communication method according to another embodiment of the present application.

[0036] FIG14 is a schematic flowchart of a communication method according to another embodiment of the present application.

[0037] FIG15 is a schematic flowchart of a communication method according to another embodiment of the present application.

[0038] FIG16 is a schematic block diagram of a remote terminal according to an embodiment of the present application.

[0039] FIG17 is a schematic block diagram of a network device according to an embodiment of the present application.

[0040] FIG18 is a schematic block diagram of a communication device according to an embodiment of the present application.

[0041] FIG19 is a schematic block diagram of a communication device according to an embodiment of the present application.

[0042] FIG20 is a schematic block diagram of a chip according to an embodiment of the present application. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0044] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Long Term Evolution (LTE) system, Advanced Long Term Evolution (LTE-A) system, New Radio (NR) system, NR system evolution system, LTE on unlicensed spectrum (LTE-U) system, NR on unlicensed spectrum (NR-based access to unlicensed spectrum, NR-U) system, Non-Terrestrial Networks (NTN) system, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (WiFi), Fifth Generation (5G) system or other communication systems.

[0045] Generally speaking, traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, mobile communication systems will not only support traditional communications, but will also support, for example, device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), vehicle-to-vehicle (V2V) communication, or vehicle-to-everything (V2X) communication, etc. The embodiments of the present application can also be applied to these communication systems.

[0046] In one embodiment, the communication system in the embodiment of the present application can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, and a standalone (SA) networking scenario.

[0047] In one embodiment, the communication system in the embodiment of the present application can be applied to an unlicensed spectrum, wherein the unlicensed spectrum can also be considered as a shared spectrum; or, the communication system in the embodiment of the present application can also be applied to an authorized spectrum, wherein the authorized spectrum can also be considered as an unshared spectrum.

[0048] The embodiments of the present application describe various embodiments in conjunction with network devices and terminal devices, wherein the terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

[0049] The terminal device can be a station (STAION, ST) in a WLAN, a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a next-generation communication system such as an NR network, or a terminal device in a future evolved Public Land Mobile Network (PLMN) network, etc.

[0050] In an embodiment of the present application, the terminal device can be deployed on land, including indoors or outdoors, handheld, wearable or vehicle-mounted; it can also be deployed on the water surface (such as ships, etc.); it can also be deployed in the air (such as airplanes, balloons and satellites, etc.).

[0051] In an embodiment of the present application, the terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, or a wireless terminal device in a smart home, etc.

[0052] As an example and not a limitation, in the embodiment of the present application, the terminal device may also be a wearable device. Wearable devices may also be called wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0053] In an embodiment of the present application, the network device may be a device for communicating with a mobile device. The network device may be an access point (AP) in a WLAN, an evolved base station (eNB or eNodeB) in LTE, or a relay station or access point, or a vehicle-mounted device, a wearable device, and a network device (gNB) in an NR network, or a network device in a future evolved PLMN network or a network device in an NTN network, etc.

[0054] As an example and not a limitation, in an embodiment of the present application, the network device may have a mobile feature, for example, the network device may be a mobile device. Alternatively, the network device may be a satellite or a balloon station. For example, the satellite may be a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, a high elliptical orbit (HEO) satellite, etc. Optionally, the network device may also be a base station set up in a location such as land or water.

[0055] In an embodiment of the present application, the network device can provide services for a cell, and the terminal device communicates with the network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be a cell corresponding to the network device (for example, a base station). The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0056] FIG1 exemplarily illustrates a communication system 100. The communication system includes a network device 110 and two terminal devices 120. In one embodiment, the communication system 100 may include multiple network devices 110, and each network device 110 may include a different number of terminal devices 120 within its coverage area, which is not limited in this embodiment of the present application.

[0057] In one embodiment, the communication system 100 may further include other network entities such as a Mobility Management Entity (MME) and an Access and Mobility Management Function (AMF), which is not limited in this embodiment of the present application.

[0058] Among them, the network equipment may include access network equipment and core network equipment. That is, the wireless communication system also includes multiple core networks for communicating with the access network equipment. The access network equipment can be an evolutionary base station (evolutional node B, abbreviated as eNB or e-NodeB) macro base station, micro base station (also called "small base station"), pico base station, access point (AP), transmission point (TP) or new generation base station (new generation Node B, gNodeB), etc. in a long-term evolution (LTE) system, a next-generation (mobile communication system) (next radio, NR) system or an authorized auxiliary access long-term evolution (LAA-LTE) system.

[0059] It should be understood that in the embodiments of the present application, a device having a communication function in a network / system may be referred to as a communication device. Taking the communication system shown in Figure 1 as an example, the communication device may include a network device and a terminal device having a communication function. The network device and the terminal device may be specific devices in the embodiments of the present application and will not be described in detail here. The communication device may also include other devices in the communication system, such as a network controller, a mobility management entity, and other network entities, which are not limited in the embodiments of the present application.

[0060] It should be understood that the terms "system" and "network" are often used interchangeably herein. The term "and / or" is simply a description of an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " generally indicates that the related objects are in an "or" relationship.

[0061] It should be understood that the "indication" mentioned in the embodiments of this application can be a direct indication, an indirect indication, or an indication of an association. For example, "A indicates B" can mean that A directly indicates B, for example, B can be obtained through A; it can also mean that A indirectly indicates B, for example, A indicates C, and B can be obtained through C; it can also mean that there is an association between A and B.

[0062] In the description of the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship between indication and being indicated, configuration and being configured, etc.

[0063] To facilitate understanding of the technical solutions of the embodiments of the present application, the relevant technologies of the embodiments of the present application are described below. The following relevant technologies can be arbitrarily combined with the technical solutions of the embodiments of the present application as optional solutions, and they all fall within the protection scope of the embodiments of the present application.

[0064] 1. Long Term Evolution (LTE) Device to Device (D2D) / V2X

[0065] Device-to-device communication is a sidelink (SL) transmission technology based on D2D. Unlike traditional cellular systems where communication data is received or sent through base stations, the Internet of Vehicles system uses direct terminal-to-terminal communication, resulting in higher spectrum efficiency and lower transmission latency.

[0066] 3GPP includes two transmission modes: Mode 3 and Mode 4.

[0067] Mode 3: As shown in Figure 2A, the terminal's transmission resources are allocated by the base station, and the terminal transmits data on the sidelink based on the allocated resources. The base station can allocate resources for a single transmission or for semi-static transmission.

[0068] Mode 4: As shown in FIG2B , the vehicle terminal selects a resource in the resource pool for data transmission.

[0069] In 3GPP, D2D includes different phases:

[0070] (1) Proximity-based Service (ProSe): In Rel-12 / 13, device-to-device communication is studied for ProSe scenarios, mainly targeting public safety services.

[0071] In proximity services, by configuring the location of resource pools in the time domain, for example, the resource pools are discontinuous in the time domain, the UE can transmit / receive data discontinuously on the sidelink, thereby achieving power saving.

[0072] (2) Internet of Vehicles: In Rel-14 / 15, the Internet of Vehicles system was studied for vehicle-to-vehicle communication scenarios, mainly for relatively high-speed vehicle-to-vehicle and vehicle-to-person communication services;

[0073] In V2X, since the on-board system has continuous power supply, power efficiency is not the main issue, but the delay of data transmission is the main issue. Therefore, the system design requires the terminal equipment to perform continuous transmission and reception.

[0074] (3) Wearable devices, further enhanced device-to-device (FeD2D): In Rel-14, this topic studies the scenario of wearable devices accessing the network through mobile phones, mainly targeting scenarios with low mobile speed and low power access.

[0075] In FeD2D, during the pre-research phase, 3GPP concluded that a base station could configure the discontinuous reception (DRX) parameters of a remote terminal through a relay terminal. However, because the topic did not enter the standardization phase, the specific details of how to perform DRX configuration have not been finalized.

[0076] NR V2X

[0077] Based on LTE V2X, NR V2X is not limited to broadcast scenarios, but has been further expanded to unicast and multicast scenarios, and the application of V2X is studied in these scenarios.

[0078] Similar to LTE V2X, NR V2X also includes two resource authorization modes: Mode-1 and Mode-2. Furthermore, a user may be in a mixed mode, that is, they can use Mode-1 to acquire resources and Mode-2 to acquire resources at the same time. The resource acquisition is indicated by the sidelink grant, that is, the sidelink grant indicates the time-frequency position of the corresponding Physical Sidelink Control Channel (PSCCH) and Physical Sidelink Shared Channel (PSSCH) resources.

[0079] Unlike LTE V2X, in addition to the feedback-free, UE-initiated Hybrid Automatic Repeat-reQuest (HARQ) retransmission, NR V2X introduces feedback-based HARQ retransmission, which is not limited to unicast communication but also includes multicast communication.

[0080] 3. Side-by-side L2UE-2-Network Relay Technology

[0081] Figure 3 shows the user plane protocol stack for the L2U2N relay architecture. For L2U2N relay, the SRAP sublayer sits above the control and user plane radio link control (RLC) sublayers at the PC5 and Uu interfaces. The SDAP, Packet Data Convergence Protocol (PDCP), and Radio Resource Control (RRC) sublayers of the Uu interface terminate between the remote UE and the gNB on the U2N relay. The Sidelink Relay Adaptation Protocol (SRAP), RLC, Medium Access Control (MAC), and Physical (PHY) sublayers terminate at each link (e.g., between the remote UE and the U2N relay UE, and between the U2N relay UE and the gNB).

[0082] 4. Side-by-side L2UE-2-Network Relay Technology

[0083] The protocol stack for the user plane of the L2U2N relay architecture is shown in Figure 4. For L2U2N relay, the SRAP sublayer sits above the RLC sublayers of the control and user planes at the PC5 and Uu interfaces. The SDAP, PDCP, and RRC sublayers of the Uu interface terminate between the remote UE and the gNB on the U2N relay, while the SRAP, RLC, MAC, and PHY sublayers terminate on each link (i.e., the link between the remote UE and the U2N relay UE, and the link between the U2N relay UE and the gNB).

[0084] The control plane protocol stack for multipath (MP) relay supported in R18, as shown in Figure 5, is the control plane protocol stack for L2 Multipath Relay using PC5 indirect path.

[0085] The following are examples of handling link failures in MP trunking:

[0086] (1) If the direct link fails and the indirect link is available, the master cell group (MCG) failure information (MCGFailureInformation) is sent to the network via the indirect link to report the direct link failure;

[0087] (2) If an indirect link fails and a direct link is available, an indirect path failure message is sent to the network via the direct link to report the indirect link failure (e.g., a PC5 failure between the remote UE and the relay UE or an air interface (Uu) failure between the relay UE and the network);

[0088] 5. Notification message: As shown in Figure 6, a notification message in sidelink can be transmitted. The U2N relay UE uses this notification process to send a notification to the connected U2N remote UE.

[0089] For example, the U2N relay UE may initiate the notification process when one of the following conditions is met:

[0090] Uu radio link failure (Radio Link Failure, RLF);

[0091] When an RRC reconfiguration (RRCReconfiguration) including a synchronous reconfiguration (reconfigurationWithSync) is received;

[0092] When cell reselection occurs;

[0093] When the RRC connection of the L2U2N relay UE fails.

[0094] FIG7 is a schematic flow chart of a communication method 700 according to an embodiment of the present application. The method can optionally be applied to the system shown in FIG1 , but is not limited thereto. The method includes at least part of the following contents.

[0095] S710: When a remote terminal has two or more relay links, determine a primary cell according to a first relay link among the two or more relay links.

[0096] In the embodiments of the present application, a link may also be referred to as a path, and a relay link may also be referred to as a relay path. A remote terminal may be connected to a network device or other terminal via two or more relay links. In this case, the remote terminal may determine a primary cell (PCell) based on one of the two or more relay links, namely, the first relay link. The primary cell may be a cell associated with the first relay link. There are multiple ways to determine the first relay path. For example, depending on whether the remote terminal is in a connected state, different ways may be used to determine the first relay path.

[0097] In one embodiment, when the remote terminal is in a connected state, the primary cell is the cell associated with the first relay link used by the remote terminal to enter the connected state. In an embodiment of the present application, if an RRC connection has been established between the remote terminal and the network device through the relay terminal, and the remote terminal is in an RRC connected state, the relay link used by the remote terminal to establish, re-establish or restore the RRC connection with the network device can be determined as the first relay link, and then the cell associated with the first relay link can be determined as the primary cell. For example, the remote terminal UE1 establishes an RRC connection with the network device through the relay terminal Relay1, and is connected to the network device through the relay terminal Relay2. One of the relay links Link1 includes UE1 to the network device via Relay1, and the other relay link Link2 includes UE1 to the network device via Relay2. If UE1 enters the RRC connected state from the RRC idle state through Link1, the cell associated with Link1 can be determined as the primary cell.

[0098] In one embodiment, the first relay link is used for at least one of the following:

[0099] Send RRC connection establishment request;

[0100] Send RRC connection reestablishment request;

[0101] Send RRC connection recovery request;

[0102] Receiving an RRC connection establishment indication;

[0103] Receive an RRC connection reestablishment indication;

[0104] Receive an RRC connection recovery indication.

[0105] For example, if the remote terminal sends an RRC connection establishment request to the network device via Link 1 via Relay 1, the cell associated with Link 1 can be determined as the primary cell. If the remote terminal receives an RRC connection establishment indication from the network device via Relay 1 via Link 1, the cell associated with Link 1 can be determined as the primary cell.

[0106] For another example, if the remote terminal sends an RRC connection reestablishment request to the network device via Link2 via Relay2, the cell associated with Link2 can be determined as the primary cell. If the remote terminal receives an RRC connection reestablishment indication from the network device via Relay2 via Link2, the cell associated with Link2 can be determined as the primary cell.

[0107] For another example, if the remote terminal sends an RRC connection recovery request to the network device via Link 3 via Relay 3, the cell associated with Link 3 can be determined as the primary cell. If the remote terminal receives an RRC connection recovery indication from the network device via Relay 3 via Link 3, the cell associated with Link 3 can be determined as the primary cell.

[0108] In one embodiment, when the remote terminal is in a non-connected state, the primary cell is the cell associated with the first relay link through which the remote terminal receives broadcast messages. In an embodiment of the present application, if no RRC connection is established between the remote terminal and the network device through the relay terminal, for example, the remote terminal is in an idle state or an inactive state, but the remote terminal can receive some broadcast messages from the network device through a certain relay terminal. In this case, the link formed by the remote device, the relay device and the network device can be used as the first relay link, and the cell associated with the first relay link can be determined as the primary cell. The cell associated with the first relay link may include the service cell of the relay terminal on the first relay link. If there are multiple relay terminals in the first relay link, and the service cells of these multiple relay terminals are not exactly the same. In this scenario, the service cell of this relay terminal can be determined as the primary cell based on other information, such as which relay terminal can receive SIB or paging messages from the network.

[0109] In one embodiment, the broadcast message includes at least one of the following: System Information Blocks (SIB), a paging message, a synchronization signal block, and a physical broadcast channel block SSB. For example, if the remote terminal UE1 receives the SIB from the network device through Relay1, and the link formed by UE1, Relay1 and the network device is Link1, the cell associated with Link1 is determined to be the primary cell. For another example, if the remote terminal UE1 receives the paging message from the network device through Relay2, and the link formed by UE1, Relay2 and the network device is Link2, the cell associated with Link2 is determined to be the primary cell. For another example, if the remote terminal UE1 receives the SSB from the network device through Relay3, and the link formed by UE1, Relay3 and the network device is Link3, the cell associated with Link3 is determined to be the primary cell.

[0110] In one embodiment, the first relay link is determined based on at least one of the following:

[0111] signal quality between the remote terminal and the relay terminal;

[0112] Relay terminal capabilities;

[0113] Service types supported by the relay terminal;

[0114] Relay service code RSC;

[0115] The cell where the relay terminal is located;

[0116] The public land mobile network PLMN where the relay terminal is located;

[0117] The measured link quality of the direct link between the remote terminal and the network device;

[0118] Service type of the remote terminal.

[0119] In the embodiment of the present application, the remote terminal, the relay terminal or the network device may determine which link to use as the first relay link for determining the primary cell based on some factors.

[0120] For example, if the signal quality of Link 1 through which the remote terminal accesses the network device via Relay 1 is lower than the signal quality of Link 2 through which the remote terminal accesses the network device via Relay 2, the cell associated with Link 2 may be selected as the primary cell.

[0121] For example, if the link through which the remote terminal accesses the network device via Relay1 is Link1, and the link through which the remote terminal accesses the network device via Relay2 is Link2, and the capability of Relay2, such as data transmission speed, is higher than that of Relay1, the cell associated with Link2 can be selected as the primary cell.

[0122] For example, if the link through which the remote terminal accesses the network device via Relay1 is Link1, and the link through which the remote terminal accesses the network device via Relay2 is Link2, if the service type supported by Relay1 is the service type expected by the remote terminal, the cell associated with Link1 can be selected as the primary cell.

[0123] For example, if the link through which the remote terminal accesses the network device via Relay1 is Link1, and the link through which the remote terminal accesses the network device via Relay2 is Link2, if the remote terminal can detect the signal of the cell where Relay1 is located, the cell where Relay1 is located can be selected as the primary cell.

[0124] For example, if the link through which the remote terminal accesses the network device via Relay1 is Link1, and the link through which the remote terminal accesses the network device via Relay2 is Link2, if the PLMN where Relay1 is located is the same as the remote terminal, the cell in the PLMN where Relay1 is located can be selected as the primary cell.

[0125] For example, if the link through which the remote terminal accesses the network device through Relay1 is Link1, and the link through which the remote terminal accesses the network device through Relay2 is Link2, and the signal quality of the network associated with the remote terminal and Relay1 measured by the remote terminal is better than the signal quality of the network associated with the remote terminal and Relay2, the cell associated with Link1 can be used as the primary cell.

[0126] For example, if the link through which the remote terminal accesses the network device via Relay1 is Link1, and the link through which the remote terminal accesses the network device via Relay2 is Link2, if the service type expected by the remote terminal matches the service type supported by Link2, the cell associated with Link2 can be selected as the primary cell.

[0127] FIG8 is a schematic flow chart of a communication method 800 according to another embodiment of the present application. The method may include one or more features of the above method. In one embodiment, the remote terminal is in a connected state, and the method further includes:

[0128] S810: The remote terminal receives configuration information, where the configuration information is used to indicate that a cell associated with the first relay link is a primary cell. For example, if the configuration information sent by the network device to the remote terminal indicates a relay terminal or a relay link, the relay link where the indicated relay terminal is located or the cell associated with the indicated relay link may be determined as the primary cell.

[0129] In one embodiment, the configuration information includes a sidelink switching configuration, which includes a target relay identifier. For example, the sidelink switching configuration may be sl-PathSwitchConfig, which may also be referred to as a sidelink path switching configuration or a sidelink path switching configuration. Based on the target relay identifier indicated by the sidelink switching configuration, the relay link where the target relay identifier is located may be determined as the first relay link, the cell where the relay terminal indicated by the target relay identifier is located may be determined as the primary cell, and the primary cell may also be determined based on the PLMN where the relay terminal indicated by the target relay identifier is located.

[0130] In one embodiment, the method further comprises at least one of the following:

[0131] When the sidelink switching configuration includes a key-related indication, disconnecting the original relay link and reestablishing the first relay link;

[0132] Maintaining the connection of the original relay link, creating a new first relay link, and reconfiguring the primary cell-related configuration of the first relay link;

[0133] Determine whether to maintain the connection of the original relay link according to the instruction information.

[0134] In the embodiment of the present application, the key-related indication may include a key, and may also include a key change indication, etc.

[0135] For example, if a remote terminal UE1 accesses a network device through Relay1, and UE1, Relay1, and the network device form Link1, if the sl-PathSwitchConfig received by UE1 includes the target relay identifier Relay2 and a key change indication (key change), Link1 can be disconnected, and a relay link Link2 can be re-established with the network device through Relay2, and the cell associated with Link2 can be determined as the primary cell.

[0136] For another example, if remote terminal UE1 accesses the network device through Relay1, and UE1, Relay1, and the network device form Link1, if the sl-PathSwitchConfig received by UE1 includes the target relay identifier Relay2, Link1 can be maintained, and relay link Link2 can be established with the network device through Relay2. The cell associated with Link2 is determined as the primary cell, and primary cell reconfiguration is performed according to the network configuration.

[0137] In one embodiment, the indication information is used to instruct to switch the primary cell from being associated with the original relay link to being associated with the first relay link, and to reconfigure the primary cell-related configuration associated with the first relay link.

[0138] For example, if a remote terminal UE1 accesses a network device via Relay1, and UE1, Relay1, and the network device form Link1, and if the sl-PathSwitchConfig received by UE1 includes the target relay identifier Relay2 and a key change indication (key change), and includes an indication not to maintain the original link, Link1 can be disconnected, and a relay link Link2 can be re-established with the network device via Relay2, and the cell associated with Link2 can be determined as the primary cell.

[0139] For another example, if remote terminal UE1 accesses the network device through Relay1, and UE1, Relay1, and the network device form Link1, if the sl-PathSwitchConfig received by UE1 includes the target relay identifier Relay2 and an instruction not to maintain the original link, Link1 can be maintained, and relay link Link2 can be established with the network device through Relay2. The cell associated with Link2 is determined to be the primary cell, and the configuration related to the original primary cell associated with Link1 can be copied to the cell associated with Link2.

[0140] In one implementation, the primary cell-related configuration is related to at least one of the following first information:

[0141] Measurement report from remote terminal to relay terminal;

[0142] Air interface Uu measurement report of the first relay terminal;

[0143] a load of the first relay terminal;

[0144] capabilities of the first relay terminal;

[0145] The number of relay hops on each link between the remote terminal and the network device;

[0146] Power saving requirements of the first relay terminal.

[0147] In an embodiment of the present application, the relay terminal on the first relay link may include a first relay terminal. After receiving the first information, the network device may generate a primary cell-related configuration based on the first information and send the primary cell-related configuration to the remote terminal and / or the first relay terminal. For example, after receiving a measurement report from the remote terminal on the relay terminal, the network device may generate a primary cell-related configuration based on the measurement report. For another example, after receiving a Uu measurement report from the first relay terminal, the network device may generate a primary cell-related configuration based on the measurement report. For another example, the network device may generate a primary cell-related configuration based on the load of the first relay terminal, such as a small number of connected remote relays or a small amount of data on the relay terminal. For another example, the network device may generate a primary cell-related configuration based on the capabilities of the first relay terminal, such as support for carrier aggregation (CA). For another example, the network device may generate a primary cell-related configuration based on the relay link with the least number of relay hops on each link between the remote terminal and the network device. For another example, the network device may generate a primary cell-related configuration based on a first relay terminal with low power saving requirements.

[0148] In one embodiment, the first information is reported through at least one of the following: a measurement report message, a terminal assistance message, sidelink terminal information, terminal capability information, and a buffer status report (BSR) MAC CE.

[0149] In one implementation, the first information is reported via a remote terminal or a relay terminal.

[0150] FIG9 is a schematic flow chart of a communication method 900 according to an embodiment of the present application. The method can optionally be applied to the system shown in FIG1 , but is not limited thereto. The method includes at least part of the following contents.

[0151] S910: The network device sends configuration information, where the configuration information is used to indicate that a cell associated with a first relay link connected to a remote terminal is a primary cell.

[0152] In one embodiment, the remote terminal is in a connected state, the configuration information includes a sidelink switching configuration, and the sidelink switching configuration includes a target relay identifier.

[0153] FIG10 is a schematic flow chart of a communication method 1000 according to another embodiment of the present application. The method may include one or more features of the above method. In one embodiment, the method further includes:

[0154] S1010: The network device sends indication information, where the indication information is used to indicate whether to maintain the connection between the remote terminal and the original relay link.

[0155] In one embodiment, the indication information is used to instruct to switch the primary cell from being associated with the original relay link to being associated with the first relay link, and to reconfigure the primary cell-related configuration associated with the first relay link.

[0156] In one implementation, the primary cell-related configuration is related to at least one of the following first information:

[0157] Measurement report from remote terminal to relay terminal;

[0158] Uu measurement report of the first relay terminal;

[0159] a load of the first relay terminal;

[0160] capabilities of the first relay terminal;

[0161] The number of relay hops on each link between the remote terminal and the network device;

[0162] Power saving requirements of the first relay terminal.

[0163] In one embodiment, the method further comprises:

[0164] S1020. The network device receives the first information, where the first information is reported through at least one of the following: a measurement report message, a terminal assistance message, sidelink terminal information, and a BSR MAC CE.

[0165] In one implementation, the first information is reported via a remote terminal or a relay terminal.

[0166] For specific examples of the network device executing methods 900 and 1000 of this embodiment, reference can be made to the relevant descriptions of the network device, such as a base station, in the above methods 700 and 800, which will not be repeated here for the sake of brevity.

[0167] FIG11 is a schematic flowchart of a communication method 1100 according to an embodiment of the present application.

[0168] S1110: When a first relay link connection has been established between a remote terminal and a first relay terminal, determine whether to use the first relay terminal as a candidate relay terminal for a second relay link.

[0169] In an embodiment of the present application, the remote terminal can establish a first relay link connection with the network device through the first relay terminal. In this case, the communication device, such as the remote terminal, relay terminal or network terminal, can determine whether the first relay terminal can be used as a candidate relay terminal for establishing a second relay link connection with the network device based on some information. The first relay link and the second relay link can be two relay links between the remote terminal and the network device established through the same physical device (first relay terminal). The identifiers used by the remote terminal and the relay terminal on different relay links, such as layer 2 identifiers, can be different. For example, in the first relay link, the identifier of the remote terminal is UE-A, and the identifier of the first relay terminal is RelayUE-A. In the second relay link, the identifier of the remote terminal is UE-B, and the identifier of the first relay terminal is RelayUE-B.

[0170] FIG12 is a schematic flow chart of a communication method 1200 according to another embodiment of the present application. The method may include one or more features of the above method 1100. In one embodiment, the method may be performed by a remote terminal, and the method further includes:

[0171] S1210. The remote terminal receives a first message, where the first message includes user information.

[0172] S1110 determines whether to use the first relay terminal as a candidate relay terminal for the second relay link, including: S1220, when the information of the first relay terminal for establishing a connection with the remote terminal is the same as the user information, the remote terminal determines whether to use the first relay terminal as a candidate relay terminal for the second relay link of the access network device.

[0173] In an embodiment of the present application, before a remote terminal establishes a connection to a network device via a relay terminal for a second relay link, the remote terminal may receive a first message from the network device or a first relay terminal. The user information in the first message may include information about a target relay terminal. If the information about the first relay terminal establishing a connection with the remote terminal is the same as the information about the target relay terminal, it can be determined that the current scenario meets the requirement of two indirect links accessing the network via the same relay terminal. In this scenario, the remote terminal may continue to determine whether the first relay terminal can be selected as a candidate relay terminal for the second relay link to access the network device.

[0174] In one embodiment, the remote terminal determines whether to use the first relay terminal as a candidate relay terminal for the second relay link of the access network device, including: the remote terminal determines whether to use the first relay terminal as a candidate relay terminal for the second relay link of the access network device based on the candidate relay terminal influencing factors.

[0175] In one embodiment, the candidate relay terminal influencing factors include at least one of the following:

[0176] QoS requirements;

[0177] Business type;

[0178] The number of candidate relay terminals around the remote terminal;

[0179] Signal quality of candidate relay terminals;

[0180] The capability of the first relay terminal.

[0181] For example, if the first relay terminal can meet the QoS requirements as a candidate relay terminal, the first relay terminal can be used as a candidate relay terminal for the second relay link of the access network device; otherwise, the first relay terminal will not be used as a candidate relay terminal for the second relay link of the access network device.

[0182] For example, if the service types supported by the first relay terminal can meet the service types that need to be supported as a candidate relay terminal, the first relay terminal can be used as a candidate relay terminal for the second relay link of the access network device. Otherwise, the first relay terminal will not be used as a candidate relay terminal for the second relay link of the access network device.

[0183] For another example, if the number of candidate relay terminals around the remote terminal is small, for example, there is no candidate relay terminal or there is only one candidate relay terminal, the first relay terminal can be used as a candidate relay terminal for the second relay link of the access network device. Otherwise, the first relay terminal will not be used as a candidate relay terminal for the second relay link of the access network device.

[0184] For example, if there are a small number of candidate relay terminals around the remote terminal, but the signal quality of the candidate relay terminals is not good, the first relay terminal can be used as a candidate relay terminal for the second relay link of the access network device. Otherwise, the first relay terminal will not be used as a candidate relay terminal for the second relay link of the access network device.

[0185] For another example, if the capability of the first relay terminal is higher, for example, higher than other candidate relay terminals around the remote terminal, the first relay terminal can be used as a candidate relay terminal for the second relay link of the access network device; otherwise, the first relay terminal will not be used as a candidate relay terminal for the second relay link of the access network device.

[0186] FIG13 is a schematic flow chart of a communication method 1300 according to another embodiment of the present application. The method may include one or more features of the above method 1100. In one embodiment, the method may be performed by a remote terminal, and the method further includes:

[0187] S1310: The remote terminal receives a first message, where the first message includes user information.

[0188] S1110 determines whether to use the first relay terminal as a candidate relay terminal for the second relay link, including: S1320, when the information of the first relay terminal connected to the remote terminal is the same as the user information, the remote terminal sends the candidate relay terminal influencing factors to the network device, and the network device determines whether to use the first relay terminal as a candidate relay terminal for the second relay link connected to the network device.

[0189] In one embodiment, the candidate relay terminal influencing factors include at least one of the following:

[0190] QoS requirements;

[0191] Business type;

[0192] The number of candidate relay terminals around the remote terminal;

[0193] Signal quality of candidate relay terminals;

[0194] The capability of the first relay terminal.

[0195] For the first message and candidate relay terminal influencing factors in this embodiment, refer to the relevant description and examples of the previous embodiment. The main difference between this embodiment and the previous embodiment is that the remote terminal can send the candidate relay terminal influencing factors it has collected to the network device, which then determines whether to select the first relay terminal as a candidate relay terminal for accessing the second relay link of the network device based on the candidate relay terminal influencing factors. The network device can notify the remote terminal and / or the first relay terminal of the determination result.

[0196] In one embodiment, the method further comprises:

[0197] S1330. The remote terminal sends a measurement report to the network device, the measurement report including information about candidate relay terminals and information that the relay terminal corresponding to the first relay terminal and the user information is the same physical entity. In an embodiment of the present application, if the remote terminal determines the first relay terminal as a candidate relay terminal, the measurement report sent by the remote terminal to the network device may include information that the first relay terminal is a candidate relay terminal for a second relay link for the remote terminal to access the network, and may also include information that the first relay terminal and the first relay terminal with which the remote terminal has established a connection are the same physical entity.

[0198] FIG14 is a schematic flow chart of a communication method 1400 according to another embodiment of the present application. The method may include one or more features of the above method 1100. In one embodiment, the method may be performed by the first relay terminal, and the method further includes:

[0199] S1410. The first relay terminal receives a second message, where the second message includes user information.

[0200] S1110 determines whether to use itself as a candidate relay terminal for the second relay link, including: S1420, when the information of the remote terminal establishing a connection with the first relay terminal is the same as the user information, the first relay terminal determines whether to use itself as a candidate relay terminal for the second relay link for the remote terminal to access the network device.

[0201] In an embodiment of the present application, before a remote terminal establishes a connection to a network device via a relay terminal for a second relay link, the first relay terminal may receive a second message from the network device or the remote terminal. The user information in the second message may include information about the target remote terminal. If the information of the remote terminal connected to the first relay terminal is the same as the information of the target remote terminal, it can be determined that the current scenario meets the requirement of two indirect links accessing the network through the same relay terminal. In this scenario, the first relay terminal may continue to determine whether it can be selected as a candidate relay terminal for the second relay link for the remote terminal to access the network device.

[0202] In one embodiment, the first relay terminal determines whether to serve as a candidate relay terminal for the second relay link of the remote terminal accessing the network device, including: the first relay terminal determines whether to serve as a candidate relay terminal for the second relay link of the remote terminal accessing the network device based on the candidate relay terminal influencing factors.

[0203] In one embodiment, the candidate relay terminal influencing factors include at least one of the following:

[0204] capabilities of the first relay terminal;

[0205] a power saving requirement of the first relay terminal;

[0206] The load condition of the first relay terminal.

[0207] For example, if the capability of the first relay terminal is higher, for example, higher than other candidate relay terminals around the remote terminal, the first relay terminal can be used as a candidate relay terminal for the second relay link of the access network device; otherwise, the first relay terminal will not be used as a candidate relay terminal for the second relay link of the access network device.

[0208] For another example, if the power saving requirement of the first relay terminal is low, the first relay terminal can be used as a candidate relay terminal for the second relay link of the access network device; otherwise, the first relay terminal is not used as a candidate relay terminal for the second relay link of the access network device.

[0209] For another example, if the load of the first relay terminal is small, the first relay terminal can be used as a candidate relay terminal for the second relay link of the access network device; otherwise, the first relay terminal is not used as a candidate relay terminal for the second relay link of the access network device.

[0210] In one embodiment, the method further comprises:

[0211] S1430: When the first relay terminal is selected as a candidate relay terminal, the first relay terminal sends a reply message to the remote terminal.

[0212] For example, if the first relay terminal receives a second message from a remote terminal, the first relay terminal may send a reply message to the remote terminal in response to the second message, in the case of selecting itself as a candidate relay terminal.

[0213] FIG15 is a schematic flow chart of a communication method 1500 according to another embodiment of the present application. The method may include one or more features of the above method 1100. In one embodiment, the method may be performed by a network device, and the method further includes:

[0214] S1510. The network device receives a third message, where the third message includes influencing factors of candidate relay terminals.

[0215] S1110 determines whether to use the first relay terminal as a candidate relay terminal for the second relay link, including: S1520, the network device determines whether to use the first relay terminal as a candidate relay terminal for the second relay link for the remote terminal to access the network device based on the influencing factors of the candidate relay terminal.

[0216] In an embodiment of the present application, before a remote terminal establishes a connection to a network device via a relay terminal over a second relay link, the network device may receive a third message from the first relay terminal or the remote terminal. The third message may include relay terminal influencing factors. If the current scenario meets the requirement of two indirect links accessing the network via the same relay terminal, the network device may continue to determine whether the first relay terminal can be used as a candidate relay terminal for the remote terminal's second relay link to access the network device.

[0217] In one embodiment, the candidate relay terminal influencing factors include at least one of the following:

[0218] QoS requirements;

[0219] Business type;

[0220] The number of candidate relay terminals around the remote terminal;

[0221] Signal quality of candidate relay terminals;

[0222] The capability of the first relay terminal.

[0223] The factors affecting the candidate relay terminals in this embodiment may refer to the relevant descriptions and examples of the above embodiments.

[0224] In one embodiment, any of the above methods further includes: when a radio link failure (RLF) occurs on a link between the remote terminal and the first relay terminal, determining that RLF also occurs on other links between the remote terminal and the first relay terminal. For example, the relay links between the remote terminal, the first relay terminal, and the network device include Link 1 and Link 2. If it is known that Link 1 has RLF, the remote terminal, the first relay terminal, or the network device may determine that Link 2 has also experienced RLF.

[0225] In one embodiment, any of the above methods further includes: receiving a combined notification message, the combined notification message being used to indicate that two or more links between the first relay terminal and the network device are unavailable. For example, if the remote terminal or the network device receives the combined notification message from the first relay terminal, it determines, based on the notification message, that all relay links, such as Link 1 and Link 2, between the first relay terminal and the network device are unavailable.

[0226] In one embodiment, any of the above methods further includes: disconnecting the direct connection between the remote terminal and the first relay terminal, and triggering an RRC connection reestablishment process. For example, if the remote terminal receives the notification message from a relay link and determines that Link 1 and Link 2 are unavailable, it can disconnect PC 5 and directly trigger an RRC connection reestablishment process without waiting for a message from another relay link.

[0227] In one embodiment, the uplink transmission logical channel and / or the radio link control RLC channel of the relay terminal associated with the bearer of the duplicate transmission of the remote terminal are configured with different frequency sets.

[0228] In direct and indirect multipath relay (MP Relay), the primary cell (PCell) is usually on the direct path. When both paths are indirect paths, it is necessary to consider how to determine which path the PCell is on.

[0229] In the case where both paths are indirect paths, if the same physical entity (relay UE) can establish a PC5 connection with one or more remote UEs (remote UEs), the remote UEs may access the network through two links of the same relay UE (relay UE). It is necessary to consider how to handle this scenario and the possible impact of supporting this scenario.

[0230] In multipath U2N relay services, it is possible to support not only two paths, one direct and one indirect, but also two indirect paths. In this case, due to different topologies, the following improvements may be made:

[0231] 1. How to determine which path is the PCell and which path is the SCell?

[0232] 2. How to handle the situation where two indirect paths pass through the same relay?

[0233] 3. What is the impact on the current process if the relays passed through by the two indirect paths are the same?

[0234] The following uses specific examples to illustrate respectively.

[0235] Example 1: How to determine the PCell

[0236] 1. How the agreement is defined:

[0237] (1) Connected State: The path through which the remote UE enters the connected state is the cell associated with that path. For example, the path through which the remote UE sends the RRC connection establishment / reestablishment / resumption request. Another example is the path through which the remote UE receives the RRC connection establishment / reestablishment / resumption indication from the network.

[0238] (2) When the Remote UE is in the non-connected state, the path through which it receives the SIB, Paging message or SSB is the cell associated with the path.

[0239] The path through which the remote UE enters the connected state and / or receives the SIB / Paging or SSB may be determined by at least one of the following factors:

[0240] Signal quality with the relay;

[0241] Relay capability / service types supported by the relay / RSC;

[0242] Measuring the link quality of direct links;

[0243] Business type (emergency / non-emergency).

[0244] 2. Network Configuration

[0245] After the Remote UE enters the connected state, the network can configure which path is associated with the cell as the PCell. The configuration example is as follows:

[0246] 1. Indicate the target relay ID through the side path switch configuration (sl-Path Switch Config) and perform at least one of the following operations:

[0247] (1) Disconnect and then reestablish another relay path (key change required);

[0248] (2) Maintain the connection of another relay path and reconfigure the corresponding configuration (such as RLC bearer) as needed (key change may not be required)

[0249] (3) Whether the connection of another relay path can be maintained is indicated by the network.

[0250] 2. When a key change is not required, a new signaling can be used to indicate the Pcell switch. For example, the Pcell receives the instruction on relay 1, indicating that the Pcell needs to be switched to relay 2, and the corresponding Pcell configuration (such as RLC bearer) is reconfigured as needed.

[0251] The above network configuration may be related to at least one of the following:

[0252] Remote UE measurement report for relay;

[0253] Relay UE Uu measurement report;

[0254] Relay UE load (e.g., number of connected remote relays / data volume);

[0255] Relay UE capabilities (e.g., whether it supports CA);

[0256] The number of relay hops on each path;

[0257] Relay UE power saving requirements.

[0258] The above-mentioned related quantities are reported to the network by the remote UE and / or relay UE through measurement report messages and / or UE assistance messages and / or sidelink UE information / buffer status report (Buffer Status Report, BSR) MAC control element (Control Element, CE); the report can be based on network request or certain events.

[0259] Example 2: Scenario processing of two indirect paths passing through the same relay UE

[0260] Scenario description: The remote UE uses L2 ID 1 and has established link 1 with the network through the relay UE (using L2 ID A). At this time, the network configures the remote UE to establish a multipath connection. The remote UE uses L2 ID 2 to discover and establish a connection with the relay UE (using L2 ID B).

[0261] Requirement: The relay UE / network can identify this scenario, or determine whether this scenario is supported based on the relay UE's capabilities (need to define new UE capabilities).

[0262] 1. Identification before connection establishment:

[0263] Method 1: The remote UE identifies and determines whether the same relay UE can be used as a candidate relay UE

[0264] (1) After receiving the discovery message from the relay, the Remote UE identifies the User Info in the message and knows that the relay is the same relay with which it has established a connection.

[0265] (2) The Remote UE decides whether to use the relay as a candidate relay UE. This decision is made by the Proximity Services (Prose) layer and / or the Access Stratum (AS) layer. The following factors are considered when making the decision:

[0266] QoS requirements (parameters known at the ProSe layer);

[0267] Service type (ProSe layer known parameter);

[0268] Number of surrounding candidate relays (a known parameter in the ProSe layer);

[0269] Candidate relay signal quality (parameters known at the AS layer);

[0270] Relay UE capabilities (such as whether it supports enhanced 2-indirect-path).

[0271] For unknown parameters of this layer, they can be completed through inter-layer interaction.

[0272] (3) If the remote UE determines that the relay UE can be used as a candidate relay UE, it reports the candidate relay UE information to the network through measurement report information.

[0273] Method 2: The relay UE identifies and decides whether to act as a 2-indirect path relay.

[0274] (1) After receiving the Model-B discovery message from the remote UE, the relay UE identifies the User Info in the message and knows that the remote UE has established a connection with it:

[0275] (2) The Relay UE decides whether to act as a candidate relay UE. This decision is made by the Prose layer and / or the AS layer. The following factors are considered when making the decision:

[0276] Relay UE capabilities (such as whether it supports enhanced 2-indirect-path)

[0277] Relay UE power saving requirements;

[0278] Relay UE load conditions.

[0279] For unknown parameters of this layer, they can be completed through inter-layer interaction.

[0280] (3) If the relay UE confirms whether to reply to the model-B discovery message of the remote UE according to the decision.

[0281] Method 3: The remote UE identifies and reports to the network, and the network decides whether to use the relay as an MP relay.

[0282] (1) After receiving the discovery message from the relay, the Remote UE identifies the User Info in the message and knows that the relay is the same relay with which it has established a connection.

[0283] (2) The Remote UE reports the candidate relay UE (if it meets the defined conditions) information to the network through measurement report information, and at the same time indicates that the relay UE corresponding to the L2 ID is the same physical entity as the current serving relay UE (for IDLE / INACTIVE Relay).

[0284] (3) The network decides whether to use the relay as the target relay UE, taking the following factors into consideration:

[0285] QoS requirements;

[0286] Service type;

[0287] Number of surrounding candidate relays;

[0288] Candidate relay signal quality;

[0289] Relay UE capability.

[0290] Example 3: Two paths are the influence of the same physical entity

[0291] 1. Impact of RLF

[0292] If RLF occurs on any link between the remote UE and the relay UE, there is no need to wait for the other path to trigger RLF again and / or report the link failure to the network on the other path. It can be considered that RLF occurs on both links, the PC5 connection is disconnected, and the RRC connection re-establishment process is directly triggered.

[0293] 2. Impact of notification messages

[0294] The relay UE can send a combined notification message for the two links, without having to send it on both PC5 links. For example:

[0295] (1) Based on the configuration / association relationship of the PCell, for example, if a path is associated with the PCell, a notification message is sent on the path;

[0296] (2) Based on the relay UE, one of the options can be sent;

[0297] (3) Based on the signal quality, decide to send on a path with good signal quality (e.g., high transmission power);

[0298] If the Remote UE receives a notification message on at least one path, it considers that both paths are no longer available. It does not need to wait for the other path to perform the notification process again and / or report the link failure to the network on the other path. It can disconnect the PC5 connection and directly trigger the RRC connection re-establishment process.

[0299] 3. Logical channel configuration on the relay Uu interface

[0300] For the remote UE's bearer with duplicate transmission activated, the uplink transmission logical channel and / or RLC channel of the relay UE associated with the duplicate transmission bearer needs to be configured with different frequency sets to ensure that the duplicate transmission data is sent through different carriers.

[0301] In the embodiments of the present application, in a multipath relay scenario, some problems and corresponding solutions that may be caused by modeling are discussed when both paths are not directly connected.

[0302] Technical solution expansion: For the scenarios in Examples 2 and 3, it is possible to consider avoiding the use of overlapping address spaces for the same User Info when generating the L2 ID. That is, for the same User Info, the same pair of UEs can only receive information in one of the address spaces, avoiding the situation where the same pair of UEs use different L2 IDs to establish multiple links.

[0303] FIG16 is a schematic block diagram of a remote terminal 1600 according to an embodiment of the present application. The remote terminal 1600 may include:

[0304] The processing unit 1601 is configured to determine a primary cell according to a first relay link among the two or more relay links when a remote terminal has two or more relay links.

[0305] In one embodiment, when the remote terminal is in a connected state, the primary cell is a cell associated with the first relay link used by the remote terminal to enter the connected state.

[0306] In one embodiment, the first relay link is used for at least one of the following:

[0307] Send RRC connection establishment request;

[0308] Send RRC connection reestablishment request;

[0309] Send RRC connection recovery request;

[0310] Receiving an RRC connection establishment indication;

[0311] Receive an RRC connection reestablishment indication;

[0312] Receive an RRC connection recovery indication.

[0313] In one embodiment, when the remote terminal is in a non-connected state, the primary cell is a cell associated with the first relay link through which the remote terminal receives broadcast messages.

[0314] In one embodiment, the broadcast message includes at least one of the following: a system information block SIB, a paging message, a synchronization signal block, and a physical broadcast channel block SSB.

[0315] In one embodiment, the first relay link is determined based on at least one of the following:

[0316] signal quality between the remote terminal and the relay terminal;

[0317] Relay terminal capabilities;

[0318] Service types supported by the relay terminal;

[0319] Relay service code RSC;

[0320] The cell where the relay terminal is located;

[0321] The public land mobile network PLMN where the relay terminal is located;

[0322] The measured link quality of the direct link between the remote terminal and the network device;

[0323] Service type of the remote terminal.

[0324] In one embodiment, the remote terminal is in a connected state, and the remote terminal further includes:

[0325] The receiving unit 1602 is configured to receive configuration information, where the configuration information is used to indicate that the cell associated with the first relay link is a primary cell.

[0326] In one embodiment, the configuration information includes a sidelink handover configuration, and the sidelink handover configuration includes a target relay identifier.

[0327] In one embodiment, the processing unit 1601 is further configured to perform at least one of the following:

[0328] When the sidelink switching configuration includes a key-related indication, disconnecting the original relay link and reestablishing the first relay link;

[0329] Maintaining the connection of the original relay link, creating a new first relay link, and reconfiguring the primary cell-related configuration of the first relay link;

[0330] Determine whether to maintain the connection of the original relay link according to the instruction information.

[0331] In one embodiment, the indication information is used to instruct to switch the primary cell from being associated with the original relay link to being associated with the first relay link, and to reconfigure the primary cell-related configuration associated with the first relay link.

[0332] In one implementation, the primary cell-related configuration is related to at least one of the following first information:

[0333] Measurement report from remote terminal to relay terminal;

[0334] Air interface Uu measurement report of the first relay terminal;

[0335] a load of the first relay terminal;

[0336] capabilities of the first relay terminal;

[0337] The number of relay hops on each link between the remote terminal and the network device;

[0338] Power saving requirements of the first relay terminal.

[0339] In one embodiment, the first information is reported through at least one of the following: a measurement report message, a terminal assistance message, sidelink terminal information, terminal capability information, and a BSR MAC CE.

[0340] In one implementation, the first information is reported via a remote terminal or a relay terminal.

[0341] The remote terminal 1600 of the embodiment of the present application is capable of implementing the corresponding functions of the remote terminal in the aforementioned method embodiment. The corresponding processes, functions, implementation methods, and beneficial effects of each module (sub-module, unit, or component, etc.) in the remote terminal 1600 can be found in the corresponding descriptions in the aforementioned method embodiment and will not be repeated here. It should be noted that the functions described for each module (sub-module, unit, or component, etc.) in the remote terminal 1600 of the embodiment of the application can be implemented by different modules (sub-modules, units, or components, etc.) or by the same module (sub-module, unit, or component, etc.).

[0342] FIG17 is a schematic block diagram of a network device 1700 according to an embodiment of the present application. The network device 1700 may include:

[0343] The sending unit 1701 is configured to send configuration information, where the configuration information is used to indicate that a cell associated with a first relay link connected to a remote terminal is a primary cell.

[0344] In one embodiment, the remote terminal is in a connected state, the configuration information includes a sidelink switching configuration, and the sidelink switching configuration includes a target relay identifier.

[0345] In one embodiment, the sending unit 1701 is further configured to send indication information, where the indication information is used to indicate whether to maintain the connection between the remote terminal and the original relay link.

[0346] In one embodiment, the indication information is used to instruct to switch the primary cell from being associated with the original relay link to being associated with the first relay link, and to reconfigure the primary cell-related configuration associated with the first relay link.

[0347] In one implementation, the primary cell-related configuration is related to at least one of the following first information:

[0348] Measurement report from remote terminal to relay terminal;

[0349] Uu measurement report of the first relay terminal;

[0350] a load of the first relay terminal;

[0351] capabilities of the first relay terminal;

[0352] The number of relay hops on each link between the remote terminal and the network device;

[0353] Power saving requirements of the first relay terminal.

[0354] In one embodiment, the network device further includes:

[0355] The receiving unit 1702 is configured to receive the first information, where the first information is reported via at least one of the following: a measurement report message, a terminal assistance message, sidelink terminal information, and a BSR MAC CE.

[0356] In one implementation, the first information is reported via a remote terminal or a relay terminal.

[0357] The network device 1700 of the embodiment of the present application can implement the corresponding functions of the network device in the aforementioned method embodiment. The processes, functions, implementation methods and beneficial effects corresponding to each module (sub-module, unit or component, etc.) in the network device 1700 can be found in the corresponding description in the above method embodiment, and will not be repeated here. It should be noted that the functions described in the various modules (sub-module, unit or component, etc.) in the network device 1700 of the embodiment of the application can be implemented by different modules (sub-module, unit or component, etc.) or by the same module (sub-module, unit or component, etc.).

[0358] FIG18 is a schematic block diagram of a communication device 1800 according to an embodiment of the present application. The communication device 1800 may include:

[0359] The processing unit 1801 is configured to determine whether to use the first relay terminal as a candidate relay terminal for a second relay link when a first relay link connection has been established between a remote terminal and the first relay terminal.

[0360] In one embodiment, the communication device is a remote terminal, and the communication device further includes:

[0361] A first receiving unit 1802 is configured to receive a first message, where the first message includes user information;

[0362] The processing unit 1801 is further configured to determine whether to use the first relay terminal as a candidate relay terminal for a second relay link accessing the network device when the information of the first relay terminal establishing a connection with the remote terminal is the same as the user information.

[0363] In one embodiment, the processing unit 1801 is further configured to determine, based on the candidate relay terminal influencing factors, whether to use the first relay terminal as a candidate relay terminal for the second relay link of the access network device.

[0364] In one embodiment, the communication device is a remote terminal, and the communication device further includes:

[0365] The second receiving unit 1803 is configured to receive a first message, where the first message includes user information;

[0366] The first sending unit 1804 is used to send the candidate relay terminal influencing factors to the network device when the information of the first relay terminal establishing a connection with the remote terminal is the same as the user information, and the network device determines whether to use the first relay terminal as a candidate relay terminal for the second relay link accessing the network device.

[0367] In one embodiment, the candidate relay terminal influencing factors include at least one of the following:

[0368] QoS requirements;

[0369] Business type;

[0370] The number of candidate relay terminals around the remote terminal;

[0371] Signal quality of candidate relay terminals;

[0372] The capability of the first relay terminal.

[0373] In one embodiment, the communication device further includes:

[0374] The second sending unit 1805 is configured to send a measurement report to the network device, where the measurement report includes information of candidate relay terminals, and the relay terminal corresponding to the first relay terminal and the user information is the same physical entity.

[0375] In one embodiment, the communication device is a first relay terminal, and the communication device further includes:

[0376] The third receiving unit 1806 is configured to receive a second message, where the second message includes user information;

[0377] The processing unit 1801 is further configured to determine whether to serve as a candidate relay terminal for the second relay link for the remote terminal to access the network device when the information of the remote terminal connected to the first relay terminal is the same as the user information.

[0378] In one embodiment, the processing unit 1801 is further configured to determine, based on the candidate relay terminal influencing factors, whether to use the first relay terminal as a candidate relay terminal for the second relay link for the remote terminal to access the network device.

[0379] In one embodiment, the candidate relay terminal influencing factors include at least one of the following:

[0380] capabilities of the first relay terminal;

[0381] a power saving requirement of the first relay terminal;

[0382] The load condition of the first relay terminal.

[0383] In one embodiment, the communication device further includes:

[0384] The third sending unit 1807 is configured to send a reply message to the remote terminal when the first relay terminal is taken as a candidate relay terminal.

[0385] In one embodiment, the communication device is a network device, and the communication device further includes:

[0386] The fourth receiving unit 1808 is configured to receive a third message, where the third message includes an influencing factor of a candidate relay terminal;

[0387] The processing unit 1801 is further configured to determine, based on the influencing factor of the candidate relay terminal, whether to use the first relay terminal as a candidate relay terminal for the second relay link for the remote terminal to access the network device.

[0388] In one embodiment, the candidate relay terminal influencing factors include at least one of the following:

[0389] QoS requirements;

[0390] Business type;

[0391] The number of candidate relay terminals around the remote terminal;

[0392] Signal quality of candidate relay terminals;

[0393] The capability of the first relay terminal.

[0394] In one embodiment, the processing unit 1801 is further configured to determine that RLF also occurs in other links between the remote terminal and the first relay terminal when a radio link failure (RLF) occurs in one link between the remote terminal and the first relay terminal.

[0395] In one embodiment, the communication device further includes:

[0396] The fifth receiving unit 1809 is configured to receive a combined notification message, where the combined notification message is used to indicate that two or more links between the first relay terminal and the network device are unavailable.

[0397] In one embodiment, the processing unit 1801 is further configured to disconnect the direct connection between the remote terminal and the first relay terminal, and trigger an RRC connection reestablishment process.

[0398] In one embodiment, the uplink transmission logical channel and / or RLC channel of the relay terminal associated with the bearer of the duplicate transmission of the remote terminal is configured with different frequency sets.

[0399] The communication device 1800 of the embodiment of the present application can implement the corresponding functions of the communication device in the aforementioned method embodiment. The processes, functions, implementation methods and beneficial effects corresponding to the various modules (sub-modules, units or components, etc.) in the communication device 1800 can be found in the corresponding descriptions in the above-mentioned method embodiments, and will not be repeated here. It should be noted that the functions described in the various modules (sub-modules, units or components, etc.) in the communication device 1800 of the embodiment of the application can be implemented by different modules (sub-modules, units or components, etc.) or by the same module (sub-module, unit or component, etc.).

[0400] Figure 19 is a schematic structural diagram of a communication device 1900 according to an embodiment of the present application. The communication device 1900 includes a processor 1910, which can call and execute a computer program from a memory to enable the communication device 1900 to implement the method in the embodiment of the present application.

[0401] In one embodiment, the communication device 1900 may further include a memory 1920. The processor 1910 may call and execute a computer program from the memory 1920 to enable the communication device 1900 to implement the method in the embodiment of the present application.

[0402] The memory 1920 may be a separate device independent of the processor 1910 , or may be integrated into the processor 1910 .

[0403] In one embodiment, the communication device 1900 may further include a transceiver 1930 , and the processor 1910 may control the transceiver 1930 to communicate with other devices. Specifically, the transceiver 1930 may send information or data to other devices, or receive information or data sent by other devices.

[0404] The transceiver 1930 may include a transmitter and a receiver. The transceiver 1930 may further include an antenna, and the number of antennas may be one or more.

[0405] In one embodiment, the communication device 1900 may be a network device of an embodiment of the present application, and the communication device 1900 may implement the corresponding processes implemented by the network device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0406] In one embodiment, the communication device 1900 may be a terminal device of an embodiment of the present application, and the communication device 1900 may implement the corresponding processes implemented by the terminal device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0407] In one embodiment, the communication device 1900 may be the communication device of the embodiment of the present application, and the communication device 1900 may implement the corresponding processes implemented by the communication device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0408] 20 is a schematic structural diagram of a chip 2000 according to an embodiment of the present application. The chip 2000 includes a processor 2010, which can call and execute a computer program from a memory to implement the method according to the embodiment of the present application.

[0409] In one embodiment, the chip 2000 may further include a memory 2020. The processor 2010 may call and execute a computer program from the memory 2020 to implement the method executed by the terminal device, network device, or communication device in the embodiment of the present application.

[0410] The memory 2020 may be a separate device independent of the processor 2010 , or may be integrated into the processor 2010 .

[0411] In one embodiment, the chip 2000 may further include an input interface 2030. The processor 2010 may control the input interface 2030 to communicate with other devices or chips, and specifically, may obtain information or data sent by other devices or chips.

[0412] In one embodiment, the chip 2000 may further include an output interface 2040. The processor 2010 may control the output interface 2040 to communicate with other devices or chips, and specifically, may output information or data to other devices or chips.

[0413] In one embodiment, the chip can be applied to the network device in the embodiments of the present application, and the chip can implement the corresponding processes implemented by the network device in each method of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0414] In one embodiment, the chip can be applied to the terminal device in the embodiments of the present application, and the chip can implement the corresponding processes implemented by the terminal device in each method of the embodiments of the present application. For the sake of brevity, they will not be repeated here.

[0415] In one embodiment, the chip can be applied to the communication device in the embodiment of the present application, and the chip can implement the corresponding processes implemented by the communication device in each method of the embodiment of the present application. For the sake of brevity, it will not be repeated here.

[0416] The chips used in communication equipment, network equipment and terminal equipment can be the same chip or different chips.

[0417] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0418] The processor mentioned above may be a general-purpose processor, a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or other programmable logic devices, transistor logic devices, discrete hardware components, etc. The general-purpose processor mentioned above may be a microprocessor or any conventional processor, etc.

[0419] The memory mentioned above may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. The non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM).

[0420] It should be understood that the above-mentioned memories are exemplary but not restrictive. For example, the memories in the embodiments of the present application may also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM RAM (DR RAM), etc. In other words, the memories in the embodiments of the present application are intended to include, but are not limited to, these and any other suitable types of memories.

[0421] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function in accordance with the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode to another website, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0422] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0423] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0424] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A communication method, comprising: When the remote terminal has two or more relay links, determining a primary cell according to a first relay link among the two or more relay links.

2. The method according to claim 1, wherein, When the remote terminal is in a connected state, the primary cell is a cell associated with the first relay link used by the remote terminal to enter the connected state.

3. The method according to claim 2, wherein The first relay link is used for at least one of the following: Sending an RRC connection establishment request; Sending an RRC connection reestablishment request; Sending an RRC connection resume request; Receiving an RRC connection establishment indication; Receiving an RRC connection reestablishment indication; Receiving an RRC connection resume indication.

4. The method according to claim 1, wherein, When the remote terminal is in a non-connected state, the primary cell is a cell associated with the first relay link through which the remote terminal receives broadcast messages.

5. The method according to claim 4, wherein, The broadcast message includes at least one of the following: System Information Block SIB, paging message, Synchronization Signal Block, and Physical Broadcast Channel Block SSB.

6. The method according to any one of claims 1 to 5, wherein The first relay link is determined based on at least one of the following: The signal quality between the remote terminal and the relay terminal; The capabilities of the relay terminal; The service types supported by the relay terminal; Relay Service Code RSC; The cell where the relay terminal is located; The Public Land Mobile Network PLMN where the relay terminal is located; The link quality of the direct link measured between the remote terminal and the network device; The service type of the remote terminal.

7. The method according to any one of claims 1 to 4, wherein When the remote terminal is in a connected state, the method further includes: The remote terminal receives configuration information, and the configuration information is used to indicate that the cell associated with the first relay link is the primary cell.

8. The method according to claim 7, wherein, The configuration information includes a sidelink handover configuration, and the sidelink handover configuration includes a target relay identifier.

9. The method according to claim 8, wherein, The method further includes at least one of the following: When the sidelink handover configuration includes a key-related indication, disconnect the connection of the original relay link and reconstruct the first relay link; Keep the connection of the original relay link, create the first relay link, and reconfigure the primary cell-related configuration of the first relay link; Determine whether to keep the connection of the original relay link according to the indication information.

10. The method according to claim 9, wherein, The indication information is used to indicate to switch the primary cell from being associated with the original relay link to being associated with the first relay link, and reconfigure the primary cell-related configuration associated with the first relay link.

11. The method according to claim 10, wherein, The primary cell-related configuration is related to at least one of the following first information: The measurement report of the remote terminal on the relay terminal; The radio interface Uu measurement report of the first relay terminal; The load of the first relay terminal; The capabilities of the first relay terminal; The number of relay hops on each link between the remote terminal and the network device; The power saving requirement of the first relay terminal.

12. The method according to claim 11, wherein, The first information is reported through at least one of the following: measurement report message, terminal assistance message, sidelink terminal information, terminal capability information, BSR MAC CE.

13. The method according to claim 11 or 12, wherein The first information is reported by the remote terminal or the relay terminal.

14. A communication method, comprising: The network device sends configuration information, and the configuration information is used to indicate that the cell associated with the first relay link connected to the remote terminal is the primary cell.

15. The method according to claim 14, wherein, The remote terminal is in a connected state, the configuration information includes sidelink handover configuration, and the sidelink handover configuration includes a target relay identifier.

16. The method according to claim 14, wherein The method further includes: The network device sends indication information for indicating whether to maintain the connection between the remote terminal and the original relay link.

17. The method according to claim 16, wherein, The indication information is used to indicate to switch the primary cell from being associated with the original relay link to being associated with the first relay link, and reconfigure the configurations related to the primary cell associated with the first relay link.

18. The method according to claim 17, wherein The configurations related to the primary cell are related to at least one of the following first information: The measurement report of the remote terminal on the relay terminal; The Uu measurement report of the first relay terminal; The load of the first relay terminal; The capability of the first relay terminal; The relay hop count on each link between the remote terminal and the network device; The power saving requirement of the first relay terminal.

19. The method according to claim 18, wherein, The method further includes: The network device receives the first information, and the first information is reported through at least one of the following: measurement report message, terminal assistance message, sidelink terminal information, BSR MAC CE.

20. The method according to claim 18 or 19, wherein The first information is reported by the remote terminal or the relay terminal.

21. A communication method, including: When a first relay link connection has been established between a remote terminal and a first relay terminal, determining whether to use the first relay terminal as a candidate relay terminal for a second relay link.

22. The method according to claim 21, wherein, The method further includes: The remote terminal receives a first message including user information; Determining whether to use the first relay terminal as a candidate relay terminal for a second relay link includes: when the information of the first relay terminal connected to the remote terminal is the same as the user information, the remote terminal determines whether to use the first relay terminal as a candidate relay terminal for a second relay link to access the network device.

23. The method according to claim 22, wherein, The remote terminal determining whether to use the first relay terminal as a candidate relay terminal for a second relay link to access the network device includes: The remote terminal determines whether to use the first relay terminal as a candidate relay terminal for a second relay link to access the network device according to the candidate relay terminal influencing factors.

24. The method according to claim 21, wherein, The method further includes: The remote terminal receives a first message including user information; Determining whether to use the first relay terminal as a candidate relay terminal for a second relay link includes: when the information of the first relay terminal connected to the remote terminal is the same as the user information, the remote terminal sends the candidate relay terminal influencing factors to the network device, and the network device determines whether to use the first relay terminal as a candidate relay terminal for a second relay link to access the network device.

25. The method according to claim 23 or 24, wherein The candidate relay terminal influencing factors include at least one of the following: QoS requirement; Service type; The number of candidate relay terminals around the remote terminal; The signal quality of the candidate relay terminal; The capability of the first relay terminal.

26. The method according to any one of claims 22 to 25, wherein, The method further includes: The remote terminal sends a measurement report to the network device, where the measurement report includes information about candidate relay terminals, and the relay terminal corresponding to the first relay terminal and the user information is the same physical entity.

27. The method according to claim 21, wherein, The method further includes: The first relay terminal receives a second message, where the second message includes user information; Determining whether to use itself as a candidate relay terminal for a second relay link includes: when the information of the remote terminal connected to the first relay terminal is the same as the user information, the first relay terminal determines whether to use itself as a candidate relay terminal for the second relay link through which the remote terminal accesses the network device.

28. The method according to claim 27, wherein, The first relay terminal determines whether to use itself as a candidate relay terminal for the second relay link through which the remote terminal accesses the network device, including: The first relay terminal determines whether to use the first relay terminal as a candidate relay terminal for the second relay link through which the remote terminal accesses the network device according to candidate relay terminal influencing factors.

29. The method according to claim 28, wherein The candidate relay terminal influencing factors include at least one of the following: The capability of the first relay terminal; The power saving requirement of the first relay terminal; The load condition of the first relay terminal.

30. The method according to any one of claims 27 to 29, wherein, The method further includes: When the first relay terminal is used as a candidate relay terminal, the first relay terminal sends a reply message to the remote terminal.

31. The method according to claim 21, wherein, The method further includes: The network device receives a third message, where the third message includes candidate relay terminal influencing factors; Determining whether to use the first relay terminal as a candidate relay terminal for a second relay link includes: the network device determines whether to use the first relay terminal as a candidate relay terminal for the second relay link through which the remote terminal accesses the network device according to the candidate relay terminal influencing factors.

32. The method according to claim 31, wherein, The candidate relay terminal influencing factors include at least one of the following: QoS requirement; Service type; The number of candidate relay terminals around the remote terminal; The signal quality of candidate relay terminals; The capability of the first relay terminal.

33. The method according to any one of claims 21 to 32, wherein, The method further includes: When a radio link failure (RLF) occurs in one link between the remote terminal and the first relay terminal, it is determined that RLF also occurs in other links between the remote terminal and the first relay terminal.

34. The method according to any one of claims 21 to 33, wherein The method further includes: Receiving a merged notification message, where the merged notification message is used to indicate that two or more links between the first relay terminal and the network device are unavailable.

35. The method according to claim 33 or 34, wherein, The method further includes: Disconnecting the direct connection between the remote terminal and the first relay terminal and triggering an RRC connection reestablishment process.

36. The method according to any one of claims 21 to 35, wherein, Configuring different frequency sets for the uplink transport logical channel and / or the radio link control (RLC) channel of the relay terminal associated with the duplicate transmission of the bearer of the remote terminal.

37. A remote terminal, including: A processing unit, configured to determine a primary cell according to a first relay link among two or more relay links when the remote terminal has two or more relay links.

38. The remote terminal according to claim 37, wherein, When the remote terminal is in the connected state, the primary cell is the cell associated with the first relay link used by the remote terminal to enter the connected state.

39. The remote terminal according to claim 38, wherein, The first relay link is used for at least one of the following: Sending an RRC connection establishment request; Sending an RRC connection reestablishment request; Sending an RRC connection resume request; Receiving an RRC connection establishment indication; Receiving an RRC connection reestablishment indication; Receiving an RRC connection resume indication.

40. The remote terminal according to claim 37, wherein, When the remote terminal is in the non-connected state, the primary cell is the cell associated with the first relay link through which the remote terminal receives broadcast messages.

41. The remote terminal according to claim 40, wherein, The broadcast message includes at least one of the following: System Information Block SIB, paging message, Synchronization Signal Block, and Physical Broadcast Channel Block SSB.

42. The remote terminal according to any one of claims 37 to 41, wherein, The first relay link is determined based on at least one of the following: The signal quality between the remote terminal and the relay terminal; The capabilities of the relay terminal; The service types supported by the relay terminal; Relay Service Code RSC; The cell where the relay terminal is located; The Public Land Mobile Network PLMN where the relay terminal is located; The link quality of the direct link measured between the remote terminal and the network device; The service type of the remote terminal.

43. The remote terminal according to any one of claims 37 to 40, wherein, When the remote terminal is in the connected state, the remote terminal further includes: A receiving unit, configured to receive configuration information, where the configuration information is used to indicate that the cell associated with the first relay link is the primary cell.

44. The remote terminal according to claim 43, wherein, The configuration information includes a sidelink handover configuration, and the sidelink handover configuration includes a target relay identifier.

45. The remote terminal according to claim 44, wherein, The processing unit is further configured to perform at least one of the following: When the sidelink handover configuration includes a key-related indication, disconnect the connection of the original relay link and reestablish the first relay link; Keep the connection of the original relay link, establish a new first relay link, and reconfigure the primary cell-related configuration of the first relay link; Determine whether to keep the connection of the original relay link according to the indication information.

46. The remote terminal according to claim 45, wherein, The indication information is used to indicate to switch the primary cell from being associated with the original relay link to being associated with the first relay link, and reconfigure the primary cell-related configuration associated with the first relay link.

47. The remote terminal according to claim 46, wherein, The primary cell-related configuration is related to at least one of the following first information: The measurement report of the remote terminal on the relay terminal; The radio interface Uu measurement report of the first relay terminal; The load of the first relay terminal; The capabilities of the first relay terminal; The number of relay hops on each link between the remote terminal and the network device; The power saving requirement of the first relay terminal.

48. The remote terminal according to claim 47, wherein, The first information is reported through at least one of the following: measurement report message, terminal assistance message, sidelink terminal information, terminal capability information, BSR MAC CE.

49. The remote terminal according to claim 47 or 48, wherein, The first information is reported by the remote terminal or the relay terminal.

50. A network device, including: A sending unit, configured to send configuration information, where the configuration information is used to indicate that the cell associated with the first relay link connected to the remote terminal is the primary cell.

51. The network device according to claim 50, wherein, When the remote terminal is in the connected state, the configuration information includes a sidelink handover configuration, and the sidelink handover configuration includes a target relay identifier.

52. The network device according to claim 50, wherein, The sending unit is further configured to send indication information, where the indication information is used to indicate whether to keep the connection between the remote terminal and the original relay link.

53. The network device according to claim 52, wherein, The indication information is used to indicate switching the primary cell from being associated with the original relay link to being associated with the first relay link, and reconfiguring the configurations related to the primary cell associated with the first relay link.

54. The network device according to claim 53, wherein, The configurations related to the primary cell are related to at least one of the following first information: Measurement reports of the remote terminal on the relay terminal; Uu measurement reports of the first relay terminal; Load of the first relay terminal; Capabilities of the first relay terminal; Relay hops on each link between the remote terminal and the network device; Power saving requirements of the first relay terminal.

55. The network device according to claim 54, wherein, The network device further includes: A receiving unit, configured to receive the first information, where the first information is reported through at least one of the following: measurement report messages, terminal assistance messages, sidelink terminal information, BSR MAC CE.

56. The network device according to claim 54 or 55, wherein, The first information is reported by the remote terminal or the relay terminal.

57. A communication device, including: A processing unit, configured to determine whether to use the first relay terminal as a candidate relay terminal for a second relay link when a first relay link connection has been established between the remote terminal and the first relay terminal.

58. The communication device according to claim 57, wherein, The communication device is a remote terminal, and the communication device further includes: a first receiving unit, configured to receive a first message, where the first message includes user information; The processing unit is further configured to determine whether to use the first relay terminal as a candidate relay terminal for a second relay link to access the network device when the information of the first relay terminal connected to the remote terminal is the same as the user information.

59. The communication device according to claim 58, wherein, The processing unit is further configured to determine whether to use the first relay terminal as a candidate relay terminal for a second relay link to access the network device according to candidate relay terminal influencing factors.

60. The communication device according to claim 57, wherein, The communication device is a remote terminal, and the communication device further includes: A second receiving unit, configured to receive a first message, where the first message includes user information; A first sending unit, configured to send candidate relay terminal influencing factors to the network device when the information of the first relay terminal connected to the remote terminal is the same as the user information, and the network device determines whether to use the first relay terminal as a candidate relay terminal for a second relay link to access the network device.

61. The communication device according to claim 59 or 60, wherein, The candidate relay terminal influencing factors include at least one of the following: QoS requirements; Service type; The number of candidate relay terminals around the remote terminal; Signal quality of the candidate relay terminal; Capabilities of the first relay terminal.

62. The communication device according to any one of claims 58 to 61, wherein, The communication device further includes: A second sending unit, configured to send a measurement report to the network device, where the measurement report includes information of the candidate relay terminal, and the relay terminal corresponding to the first relay terminal and the user information is the same physical entity.

63. The communication device according to claim 57, wherein, The communication device is the first relay terminal, and the communication device further includes: A third receiving unit, configured to receive a second message, where the second message includes user information; The processing unit is further configured to determine whether to use itself as a candidate relay terminal for a second relay link for the remote terminal to access the network device when the information of the remote terminal connected to the first relay terminal is the same as the user information.

64. The communication device according to claim 63, wherein, The processing unit is further configured to determine whether to use the first relay terminal as a candidate relay terminal for a second relay link through which the remote terminal accesses the network device according to the influencing factors of the candidate relay terminal.

65. The communication device according to claim 64, wherein, The influencing factors of the candidate relay terminal include at least one of the following: The capabilities of the first relay terminal; The power saving requirements of the first relay terminal; The load condition of the first relay terminal.

66. The communication device according to any one of claims 63 to 65, wherein, The communication device further includes: A third sending unit, configured to send a reply message to the remote terminal when the first relay terminal is used as a candidate relay terminal.

67. The communication device according to claim 57, wherein, The communication device is a network device, and the communication device further includes: A fourth receiving unit, configured to receive a third message, where the third message includes the influencing factors of the candidate relay terminal; The processing unit is further configured to determine whether to use the first relay terminal as a candidate relay terminal for a second relay link through which the remote terminal accesses the network device according to the influencing factors of the candidate relay terminal.

68. The communication device according to claim 67, wherein, The influencing factors of the candidate relay terminal include at least one of the following: QoS requirements; Service type; The number of candidate relay terminals around the remote terminal; The signal quality of the candidate relay terminal; The capabilities of the first relay terminal.

69. The communication device according to any one of claims 57 to 68, wherein, The processing unit is further configured to determine that other links between the remote terminal and the first relay terminal also have a radio link failure (RLF) when a link between the remote terminal and the first relay terminal has an RLF.

70. The communication device according to any one of claims 57 to 69, wherein, The communication device further includes: A fifth receiving unit, configured to receive a combined notification message, where the combined notification message is used to indicate that two or more links between the first relay terminal and the network device are unavailable.

71. The communication device according to claim 69 or 70, wherein, The processing unit is further configured to disconnect the direct connection between the remote terminal and the first relay terminal and trigger an RRC connection reestablishment process.

72. The communication device according to any one of claims 57 to 71, wherein, Configure different frequency sets for the uplink transmission logical channel and / or RLC channel of the relay terminal associated with the replicated transmission of the remote terminal.

73. A terminal device, comprising: A transceiver, a processor, and a memory, where the memory is used to store a computer program, the transceiver is used to communicate with other devices, and the processor is used to call and run the computer program stored in the memory, so that the terminal device executes the method according to any one of claims 1 to 13.

74. A network device, comprising: A transceiver, a processor, and a memory, where the memory is used to store a computer program, the transceiver is used to communicate with other devices, and the processor is used to call and run the computer program stored in the memory, so that the network device executes the method according to any one of claims 14 to 20.

75. A communication device, comprising: A transceiver, a processor, and a memory, where the memory is used to store a computer program, the transceiver is used to communicate with other devices, and the processor is used to call and run the computer program stored in the memory, so that the communication device executes the method according to any one of claims 21 to 36.

76. A chip, comprising: A processor, configured to call and run a computer program from a memory, so that the device installed with the chip executes the method according to any one of claims 1 to 36.

77. A computer-readable storage medium for storing a computer program, which when run on a device causes the device to perform the method according to any one of claims 1 to 36.

78. A computer program product comprising computer program instructions that cause a computer to perform the method according to any one of claims 1 to 36.

79. A computer program that causes a computer to perform the method according to any one of claims 1 to 36.

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