Communication method, apparatus and device, chip, and storage medium

Abstract

Embodiments of the present application provide a communication method, applied to a first device. One or more relay terminal devices are present on a first link between the first device and a second device. The method comprises: when a timer expires, disconnecting a first link, wherein a start condition of the timer is related to the state of the first link changing or being about to change. That is, the first device can trigger the start of the timer on the basis of the state of the first link changing or being about to change, if the timer does not expire, the first device does not perform the operation of disconnecting the first link, and if the timer expires, the first device disconnects the first link. In this way, when the state of the first link changes or is about to change, the data cached on the first link can be transmitted as completely as possible before the first device disconnects the first link, thereby avoiding data loss of the data that has not been transmitted completely.

Description

Communication method, device, equipment, chip and storage medium Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and specifically to a communication method, apparatus, device, chip, and storage medium. Background Art

[0002] In a UE-to-Network (U2N) relay service scenario, a remote terminal can connect to the network through one or more relays. When a handover occurs to the remote terminal, some data may be cached on the relay terminal between the remote terminal and the network and not transmitted to the target entity (for example, uplink data sent by the remote terminal is not transmitted to the network; or downlink data sent by the network is not transmitted to the remote terminal). As a result, data loss occurs when the remote terminal switches to a new cell or base station.

[0003] Summary of the Invention

[0004] Embodiments of the present application provide a communication method, apparatus, device, chip, and storage medium.

[0005] In a first aspect, an embodiment of the present application provides a communication method, which is applied to a first device, and one or more relay terminal devices exist on a first link between the first device and the second device. The method includes: disconnecting the first link when a timer expires; wherein the start condition of the timer is related to a state change or an imminent state change of the first link.

[0006] In a second aspect, an embodiment of the present application provides a communication method, which is applied to a third device. The first link where the third device is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device. The method includes: sending first information to a fourth device on the first link, and the first information is used to determine whether there is any unfinished transmission data on the first link.

[0007] In a third aspect, an embodiment of the present application provides a communication method, which is applied to a fourth device, and the first link where the fourth device is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device. The method includes: receiving first information from a third device on the first link, and the first information is used to determine whether there is any unfinished transmission data on the first link.

[0008] In a fourth aspect, an embodiment of the present application provides a communication method, which is applied to a fourth relay terminal device, where the fourth relay terminal device is located on a first link between a first remote terminal device and a target device, and there are one or more relay terminal devices on the first link. The method includes: upon receiving a first positive acknowledgement ACK from a fifth device on the first link, sending a second ACK to a sixth device on the first link; wherein the fifth device is the next-hop device of the fourth relay terminal device in the data transmission direction, and the sixth device is the previous-hop device of the fourth relay terminal device in the data transmission direction; the first ACK is used to indicate that the fifth device has successfully received the first data from the fourth relay terminal device; and the second ACK is used to indicate that the fourth relay terminal device has successfully received the first data from the sixth device.

[0009] In the fifth aspect, an embodiment of the present application provides a communication device, wherein there are one or more relay terminal devices on the first link between the device and a second device, and the device includes: a processing unit, configured to disconnect the first link when a timer expires; wherein the start condition of the timer is related to a state change or an imminent state change of the first link.

[0010] In the sixth aspect, an embodiment of the present application provides a communication device, wherein the first link on which the device is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device, and the device includes: a first communication unit, configured to send first information to a fourth device on the first link, and the first information is used to determine whether there is any unfinished transmission data on the first link.

[0011] In the seventh aspect, an embodiment of the present application provides a communication device, wherein the first link on which the device is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device, and the device includes: a second communication unit, configured to receive first information from a third device on the first link, and the first information is used to determine whether there is any unfinished transmitted data on the first link.

[0012] In the eighth aspect, an embodiment of the present application provides a communication device, which is located on a first link between a first remote terminal device and a target device, and there are one or more relay terminal devices on the first link. The device includes: a third communication unit, configured to send a second ACK to a sixth device on the first link upon receiving a first positive acknowledgement ACK from a fifth device on the first link; wherein the fifth device is the next-hop device of the device in the data transmission direction, and the sixth device is the previous-hop device of the device in the data transmission direction; the first ACK is used to indicate that the fifth device has successfully received the first data from the device; and the second ACK is used to indicate that the device has successfully received the first data from the sixth device.

[0013] In a ninth aspect, an embodiment of the present application provides a communication device, comprising a processor and a memory. The memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to perform the method described in any one of the first to fourth aspects.

[0014] In a tenth aspect, an embodiment of the present application provides a chip. The chip includes: a processor configured to call and execute a computer program from a memory, so that a device equipped with the chip executes the method described in any one of the first to fourth aspects.

[0015] In an eleventh aspect, an embodiment of the present application provides a computer-readable storage medium for storing a computer program, which enables a computer to execute the method described in any one of the first to fourth aspects.

[0016] In a twelfth aspect, an embodiment of the present application provides a computer program product, comprising computer program instructions, which enable a computer to execute the method described in any one of the first to fourth aspects.

[0017] In a thirteenth aspect, an embodiment of the present application provides a computer program, which, when executed on a computer, enables the computer to execute the method described in any one of the first to fourth aspects.

[0018] Through the above technical solution, the first device can disconnect the first link when the timer expires. The timer start condition is related to the state change or impending state change of the first link. In other words, the first device can trigger the start of the timer based on the state change or impending state change of the first link. If the timer has not timed out, the first device will not perform the operation of disconnecting the first link. If the timer times out, the first link will be disconnected. In this way, when the state of the first link changes or is about to change, before the first device disconnects the first link, the data cached on the first link can be completed as much as possible, thereby avoiding the loss of untransmitted data. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0020] FIG1-1 is a schematic diagram of resource selection corresponding to the first mode provided in an embodiment of the present application;

[0021] Figure 1-2 is a schematic diagram of resource selection corresponding to the second mode provided in an embodiment of the present application;

[0022] FIG2 is a schematic diagram of a user plane protocol stack of a sideline L2U2N relay architecture provided in an embodiment of the present application;

[0023] FIG3 is a schematic diagram of an example of a communication scenario applicable to an embodiment of the present application provided by an embodiment of the present application;

[0024] FIG4 is a flow chart of a communication method according to an embodiment of the present application;

[0025] FIG5 is a second flow chart of a communication method provided in an embodiment of the present application;

[0026] FIG6 is a third flow chart of a communication method provided in an embodiment of the present application;

[0027] FIG7 is a flow chart of an example of a feedback method provided in an embodiment of the present application;

[0028] FIG8 is a schematic diagram of the first structure of a communication device provided in an embodiment of the present application;

[0029] FIG9 is a second schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0030] FIG10 is a third schematic diagram of the structure of the communication device provided in an embodiment of the present application;

[0031] FIG11 is a fourth schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0032] FIG12 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0033] FIG13 is a schematic structural diagram of a chip according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] The following will describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] The technical solutions of the embodiments of the present application can be applied to various side communication systems. 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 explained below. The following related technologies can be arbitrarily combined with the technical solutions of the embodiments of the present application as optional solutions, and they all fall within the protection scope of the embodiments of the present application.

[0036] 1. Device to Device (D2D) / Vehicle to Everything (V2X) in Long Term Evolution (LTE)

[0037] Device-to-device communication is a sidelink (SL) transmission technology based on D2D. Unlike traditional cellular systems, where communication data is received or transmitted via base stations, the connected vehicle system uses direct end-to-end communication, resulting in higher spectrum efficiency and lower transmission latency. The 3rd Generation Partnership Project (3GPP) defines two transmission modes: Mode 1 (Mode 3) and Mode 2 (Mode 4).

[0038] Mode 1: The terminal's transmission resources are allocated by the base station (eNB). 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. As shown in Figure 1-1, the terminal's transmission resources are allocated by the base station. The base station allocates resources to the terminal via downlink based on grant signaling (Grant). The terminal transmits data on the sidelink based on the allocated resources.

[0039] Second mode: The terminal selects a resource in the resource pool for data transmission. As shown in Figure 1-2, the terminal selects a resource in the resource pool for data transmission.

[0040] In 3GPP, D2D is divided into the following different phases for research:

[0041] 1) Proximity-based Service (ProSe): In Rel-12 / 13, device-to-device communication was studied for ProSe scenarios, primarily targeting public safety services.

[0042] In ProSe, by configuring the position of the resource pool in the time domain, for example, the resource pool is non-continuous in the time domain, the UE can transmit / receive data discontinuously on the sidelink, thereby achieving power saving.

[0043] 2) V2X: In Rel-14 / 15, the vehicle-to-vehicle (V2X) system studied vehicle-to-vehicle (V2V) communication scenarios, primarily targeting relatively high-speed vehicle-to-vehicle and vehicle-to-pedestrian communication services.

[0044] 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.

[0045] 3) Wearable devices (FeD2D): In Rel-14, this scenario studies the scenario of wearable devices accessing the network through mobile phones, which is mainly aimed at scenarios with low mobile speed and low power access.

[0046] In FeD2D, during the pre-research phase, 3GPP concluded that a base station can configure the discontinuous reception (DRX) parameters of a remote terminal through a relay terminal, but did not provide a conclusion on the specific details of how to perform DRX configuration.

[0047] 2. New Radio (NR) V2X

[0048] 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.

[0049] Similar to LTE V2X, NR V2X also defines two resource authorization modes: mode-1 / 2 (i.e., the first mode and the second mode mentioned above). Furthermore, the 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. 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.

[0050] 3. Side-by-side L2U2N relay technology

[0051] Figure 2 shows the user plane protocol stack for the sidelink L2U2N relay architecture. For L2U2N relay, the Sidelink Relay Adaptation Protocol (SRAP) sublayer sits above the control and user plane Radio Link Control (RLC) sublayers at the PC5 and Uu interfaces. The Service Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP), and Radio Resource Control (RRC) sublayers of the Uu interface terminate between the remote UE and the gNB of the U2N relay. The SRAP, RLC, MAC, and Physical Layer (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).

[0052] 4. Data plane operations during handover (HO)

[0053] For UEs in RRC_CONNECTED state, in the intra-NR-Access handover scenario, the following principles shall be considered for data plane processing during mobility activities to avoid data loss during HO:

[0054] 1) During HO preparation, a data plane tunnel can be established between the source gNB and the target gNB.

[0055] 2) During HO execution, user data can be forwarded from the source gNB to the target gNB, and the forwarding can be done in sequence if the source gNB receives the data packet from the User Plane Function (UPF) or the source gNB buffer has not been flushed.

[0056] 3) During HO completion, the target gNB sends a Path Switch Request message to the Access and Mobility Management Function (AMF) to inform the UE of the HO. The AMF then triggers the path switch-related signaling within the 5G Core (5GC) and the actual path switch from the source gNB to the target gNB in ​​the UPF. The source gNB can continue forwarding data if it receives data packets from the UPF or if the source gNB buffer is not empty.

[0057] The above briefly explains the relevant technologies / terms involved in the embodiments of this application, which will not be repeated in the following embodiments.

[0058] It should be understood that the terms "system" and "network" are often used interchangeably in this document. The term "and / or" in this document is merely a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this document generally indicates that the objects associated before and after are in an "or" relationship. It should also 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 relationship. For example, A indicates B, which can mean that A directly indicates B, for example, B can be obtained through A; it can also mean that A indirectly indicates B, for example, A indicates C, and B can be obtained through C; it can also mean that there is an association relationship between A and B. It should also be understood that the "correspondence" mentioned in the embodiments of this application can mean that there is a direct or indirect correspondence between the two, or it can mean that there is an association relationship between the two, or it can mean a relationship between indication and indication, configuration and configuration, etc. It should also be understood that the "predefined" or "predefined rules" mentioned in the embodiments of this application can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in devices (for example, including terminal devices and network devices). This application does not limit its specific implementation method.

[0059] It should also be understood that the embodiments of the present application do not limit the specific forms of terminal devices and network devices.

[0060] The terminal device (or terminal) in the embodiments of the present application may refer to an access terminal, user equipment (UE), a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user device. The access terminal may be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, an IoT device, a satellite handheld terminal, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a 5G network, or a terminal device in a future evolution network, etc.

[0061] The network device (or referred to as a network) in the embodiment of the present application may be an evolved base station (eNB or eNodeB) in an LTE system, or a next generation radio access network (NG RAN) device, or a base station (gNB) in an NR system, or a wireless controller in a cloud radio access network (CRAN), or the network device 120 may be a relay station, an access point, a vehicle-mounted device, a wearable device, a hub, a switch, a bridge, a router, or a network device in a future evolved public land mobile network (PLMN).

[0062] Currently, when a terminal and network are directly connected, the PDCP layer of the terminal and network determines whether to retransmit data in the buffer based on RLC feedback when sending data. For example, if no ACK is received for a certain data item, the data must be retransmitted. Otherwise, the PDCP entity may assume that the data has been acknowledged and does not need to be retransmitted.

[0063] In the L2U2N relay scenario, since the PDCP entity is an end-to-end entity (from remote UE to gNB) and the RLC entity exists on each hop (from remote UE to relay UE / from one relay to another relay / from relay to NW), the RLC feedback result of ACK does not mean that the data has been correctly transmitted to the corresponding PDCP peer, but may still be at an intermediate hop relay.

[0064] That is, in U2N relay scenarios, based on the current PDCP / RLC mechanism, data transmission / data processing in RLC Acknowledge Mode (AM) may result in data loss during the HO process. For example, when a HO occurs at a remote terminal, some data may be buffered on the relay terminal between the remote terminal and the network and not transmitted to the target entity (e.g., uplink data sent by the remote terminal is not transmitted to the network; or downlink data sent by the network is not transmitted to the remote terminal). This can lead to data loss when the remote terminal switches to a new cell or base station.

[0065] In view of this, the present application provides a communication method, apparatus, device, chip and storage medium. The method may be applicable to, for example, a U2N relay scenario or a U2U relay scenario. In this method, one or more relay terminal devices may exist on the first link between the first device and the second device. The first device may disconnect the first link when the timer times out, and the start condition of the timer is related to the state change or impending state change of the first link. That is, the first device may trigger the start of the timer based on the state change or impending state change of the first link. If the timer does not time out, the first device does not perform the operation of disconnecting the first link. If the timer times out, the first link is disconnected. In this way, when the state of the first link changes or is about to change, before the first device disconnects the first link, the data cached on the first link can be transmitted as much as possible, thereby avoiding the loss of data that has not been transmitted.

[0066] For example, FIG3 shows a schematic diagram of a communication scenario applicable to an embodiment of the present application. In the communication scenario shown in FIG3 , a remote terminal device, a target device, and a relay terminal device (such as relay terminal device #1 and relay terminal device #2 in FIG3 ) located on a link (e.g., denoted as a first link) between the remote terminal device and the target device may be included. The remote terminal device and the target device can transmit data through the relay terminal device. For example, the remote terminal device can transmit data to the target device through the relay terminal device #1 and the relay terminal device #2; for another example, the target device can transmit data to the remote terminal device through the relay terminal device #2 and the relay terminal device #1.

[0067] It should be noted that the presence of two relay terminal devices (relay terminal device #1 and relay terminal device #2) between the remote terminal device and the target device in FIG3 is merely exemplary. In other scenarios, other numbers of relay terminal devices may exist between the remote terminal device and the target device. For example, the number of relay terminal devices between the remote terminal device and the target device may be one, or three or more, and this is not limited in the present embodiment.

[0068] It should also be noted that the "link" in the embodiment of the present application can also be replaced by "path".

[0069] In some embodiments, the target device may be a network device or another remote terminal device. If the target device is a network device, the method of the embodiment of the present application may be applicable to a U2N relay scenario; if the target device is another remote terminal device, the method of the embodiment of the present application may be applicable to a U2U relay scenario.

[0070] To facilitate understanding of the technical solutions of the embodiments of the present application, the technical solutions of the present application are described in detail below through specific embodiments. The above related technologies can be combined arbitrarily with the technical solutions of the embodiments of the present application as optional solutions, and all of them fall within the scope of protection of the embodiments of the present application. The embodiments of the present application include at least part of the following contents.

[0071] FIG4 is a flow chart of a communication method according to an embodiment of the present application. In this method, one or more relay terminal devices are present on a first link between a first device and a second device. As shown in FIG4 , the method may include the following steps:

[0072] S401: When a timer times out, the first device disconnects the first link; wherein a start condition of the timer is related to a state change or an imminent state change of the first link.

[0073] Disconnecting the first link may also be understood as disconnecting the connection between the first device and the second device. The timer start condition is related to a state change or an impending state change of the first link. Alternatively, the first device may trigger the start of the timer based on a state change or an impending state change of the first link.

[0074] Exemplarily, the state change of the first link may refer to, for example, a state change of the first link, such as a state change of one or more sub-links on the first link (such as an RLF occurs in the link between a relay terminal device and an adjacent device on the first link, a link switch or a cell switch occurs in a relay terminal device, etc.).

[0075] Exemplarily, the impending state change of the first link may mean that it has been determined / determined that the state change of the first link will occur, but the state change of the first link has not yet occurred. For example, the first device (assuming the first device is a remote terminal device) has received a handover command, but the source path (the first link) has not yet been disconnected. For another example, the first device (assuming the first device is a remote terminal device) has connected to another link during the handover process, but the source path (the first link) has not yet been disconnected.

[0076] In some embodiments, the first device may be a remote terminal device, and the second device may be a network device.

[0077] For example, in the communication scenario shown in FIG3 , the first device may be the remote terminal device in FIG3 , the second device may be, for example, the target device in FIG3 , and the target device may be a network device.

[0078] In this case, the start condition of the timer may include one or more of the following 11) to 13):

[0079] 11) The remote terminal device (first device) receives first indication information from the network device, where the first indication information is used to instruct the remote terminal device to switch from the first link to another link.

[0080] That is, if the remote terminal device receives the first indication information from the network device, it can start a timer, and if the timer times out, the remote terminal device can disconnect the first link. The remote terminal device receives the first indication information from the network device and can determine that the state of the first link is about to change.

[0081] In some embodiments, the first indication information may be, for example, a HO command (e.g., an RRCReconfiguration message). The HO command may carry handover-related information, such as an indication of switching from an indirect path (first link) to a direct path / indirect path (other link) in an intra-gNB handover scenario; or an indication of switching from an indirect path (first link) to a direct path / indirect path (other link) in an inter-gNB handover scenario.

[0082] 12) The remote terminal device successfully accesses other links.

[0083] That is, if the remote terminal device successfully accesses another link (e.g., successfully sends an RRCReconfigurationComplete message to a network device on another link), a timer may be started. If the timer times out, the remote terminal device may disconnect the first link. Successful access of the remote terminal device to another link may indicate that the state of the first link is about to change.

[0084] 13) The remote terminal device receives second indication information from the first relay terminal device on the first link, where the second indication information is used to indicate that a link status change occurs between the first relay terminal device and an adjacent device on the first link.

[0085] The first relay terminal device may be, for example, any relay terminal device on the first link.

[0086] That is, if the remote terminal device receives the second indication information from any first relay terminal device on the first link, the timer may be started. If the timer times out, the remote terminal device may disconnect the first link (e.g., disconnect the link between the remote terminal device and the first relay terminal device). The remote terminal device may deem that a state change has occurred on the first link when it receives the second indication information from the first relay terminal device on the first link.

[0087] In some embodiments, the second indication information may be, for example, a notification message from the first relay terminal device.

[0088] In some embodiments, a link state change between the first relay terminal device and the adjacent device on the first link may include any of the following:

[0089] A radio link failure (RLF) occurs in the link between the first relay terminal device and the adjacent device;

[0090] The link quality between the first relay terminal device and the adjacent device is lower than a first threshold;

[0091] Link switching occurs in the first relay terminal device;

[0092] The first relay terminal device undergoes cell switching.

[0093] Among them, the link between the first relay terminal device and the adjacent device can be, for example, a Uu link or a PC5 link. Taking the communication scenario shown in Figure 3 as an example, if the first relay terminal device is relay terminal device #1, then the link between relay terminal device #1 and the adjacent device can be, for example, a PC5 link between relay terminal device #1 and the remote terminal device, or can be a PC5 link between relay terminal device #1 and relay terminal device #2. If the first relay terminal device is relay terminal device #2, then the link between relay terminal device #2 and the adjacent device can be, for example, a PC5 link between relay terminal device #2 and relay terminal device #1, or can be a Uu link between relay terminal device #2 and the target device (assuming the target device is a network device).

[0094] In some embodiments, the first device and the second device may both be remote terminal devices.

[0095] For example, in the communication scenario shown in Figure 3, the first device can be the remote terminal device in Figure 3, the second device can be, for example, the target device in Figure 3, and the target device is another remote terminal device; or, the second device can be the remote terminal device in Figure 3, the first device can be, for example, the target device in Figure 3, and the target device is another remote terminal device.

[0096] In this case, the start condition of the timer may include: the first device determines to reselect the relay terminal device between the first device and the second device.

[0097] That is, when the first device determines to reselect the relay terminal device between the first device and the second device, that is, when the first device determines to perform relay reselection, the first device may start a timer. If the timer expires, the first device may disconnect the first link. In some embodiments, after disconnecting the first link, the first device may re-establish a connection with the second device through the reselected relay terminal device.

[0098] In some embodiments, the first device may be a first network device, and the second device may be a remote terminal device.

[0099] For example, in the communication scenario shown in FIG3 , the first device (first network device) may be the target device in FIG3 , and the target device is a network device, and the second device may be, for example, the remote terminal device in FIG3 .

[0100] In this case, the start condition of the timer may include one or more of the following 21) to 24):

[0101] 21) The first network device sends third indication information to the remote terminal device, where the third indication information is used to instruct the remote terminal device to switch from the first link to another link.

[0102] That is, if the first network device sends the third indication information to the remote terminal device, a timer may be started, and if the timer times out, the first network device may disconnect the first link. The first network device sending the third indication information to the remote terminal device may indicate that the state of the first link is about to change.

[0103] In some scenarios, the first network device sending the third indication information to the remote terminal device may include a situation before the first network device sends the third indication information to the remote terminal device, for example, the first network device has determined / decided to send the third indication information to the remote terminal device but has not yet sent the third indication information. In other words, when the first network device has determined / decided to send the third indication information to the remote terminal device but has not yet sent the third indication information, the condition in 21) may be considered to be satisfied. In some scenarios, the first network device sending the third indication information to the remote terminal device may also include a situation when the first network device sends the third indication information to the remote terminal device, or when the first network device has already sent the third indication information to the remote terminal device. In other words, when the first network device sends the third indication information to the remote terminal device, or when the first network device has already sent the third indication information to the remote terminal device, the condition in 21) may be considered to be satisfied.

[0104] In some embodiments, the third indication information may be, for example, a HO command (e.g., an RRCReconfiguration message). The HO command may carry handover-related information, such as an indication of handover from an indirect path (first link) to a direct path / indirect path (other link) in an intra-gNB handover scenario; or an indication of handover from an indirect path (first link) to a direct path / indirect path (other link) in an inter-gNB handover scenario.

[0105] 22) The first network device receives fourth indication information from the remote terminal device, where the fourth indication information is used to indicate that the remote terminal device has successfully accessed other links.

[0106] That is, if the first network device receives the fourth indication information from the remote terminal device, it can start a timer, and if the timer times out, the first network device can disconnect the first link. The first network device may determine that the state of the first link is about to change when it receives the fourth indication information from the remote terminal device.

[0107] Exemplarily, the start condition 22) may be applicable to a scenario in which a remote terminal device performs an Intra-gNB handover.

[0108] In the scenario where the remote terminal device performs Intra-gNB switching, the fourth indication information may be, for example, an RRCReconfigurationComplete message from the remote terminal device, which may be used to indicate that the remote terminal device has successfully accessed the first network device from the new path (other link).

[0109] 23) The first network device receives fifth indication information from the second network device, where the fifth indication information is used to indicate that the remote terminal device has successfully accessed the second network device.

[0110] That is, if the first network device receives the fifth indication information from the second network device, it can start a timer, and if the timer times out, the first network device can disconnect the first link. The first network device may determine that the state of the first link is about to change when it receives the fifth indication information from the second network device.

[0111] Exemplarily, the start condition 23) may be applicable to a scenario in which a remote terminal device performs Inter-gNB switching.

[0112] In a scenario where the remote terminal device performs an Inter-gNB handover, the fifth indication information may, for example, be a handover request acceptance message from the second network device (target gNB), which may be used to indicate that the remote terminal device has successfully accessed the second network device.

[0113] 24) The first network device sends sixth indication information to at least one relay terminal device on the first link. The sixth indication information sent to the relay terminal device is used to instruct the relay terminal device to perform link switching.

[0114] That is, if the first network device sends the sixth indication information to at least one (one or more) relay terminal devices on the first link, a timer may be started. If the timer times out, the first network device may disconnect the first link (e.g., disconnect the link between the first network device and the at least one relay terminal device). The first network device sending the sixth indication information to at least one relay terminal device on the first link may indicate that a state change is about to occur on the first link.

[0115] In some scenarios, the first network device sending the sixth indication information to at least one relay terminal device on the first link may include a situation before the first network device sends the sixth indication information to the at least one relay terminal device, for example, the first network device has determined / decided to send the sixth indication information to the at least one relay terminal device but has not yet sent the sixth indication information. That is, when the first network device has determined / decided to send the sixth indication information to the at least one relay terminal device but has not yet sent the sixth indication information, the condition in 24) may be considered to be satisfied. In some scenarios, the first network device sending the sixth indication information to at least one relay terminal device on the first link may also include a situation when the first network device sends the sixth indication information to the at least one relay terminal device, or when the first network device has already sent the sixth indication information to the at least one relay terminal device. That is, when the first network device sends the sixth indication information to the at least one relay terminal device, or when the first network device has already sent the sixth indication information to the at least one relay terminal device, the condition in 24) may be considered to be satisfied.

[0116] In some embodiments, the sixth indication information may be, for example, an RRCReconfiguration message, which may carry handover-related information.

[0117] In some embodiments, the method may further include: when the first device receives data from the first link, the first device restarts the timer. After the first device restarts the timer, the timer may start counting again.

[0118] It is understandable that if the first device receives data from the first link, it means that there is still uncompleted transmission data cached on the first link, so the first device can restart the timer to allow the uncompleted transmission data to have more transmission time, so as to complete the transmission as much as possible.

[0119] In some embodiments, the method may further include: during the timer running, the first device stops sending data to the second device. Because the first link has currently undergone a state change or is about to undergo a state change, in this case, it is necessary to complete the transmission of data that has not been completed on the first link as much as possible, and therefore, the first device should not send data to the second device.

[0120] In some embodiments, the timing duration of the timer (timer value) may be related to one or more of the following information 31) to 36):

[0121] 31) Packet Delay Budget (PDB) for data transmitted on the first link.

[0122] In some embodiments, the data transmitted on the first link includes multiple Quality of Service (QoS) flows. The PDB of the data transmitted on the first link may be, for example, the maximum value among the PDBs of the multiple QoS flows. This allows the QoS flow with the largest PDB to complete transmission, thereby facilitating the completion of transmission of other QoS flows on the first link.

[0123] 32) The priority of the data transmitted on the first link.

[0124] In some embodiments, the higher the priority of the data, the higher the reliability requirement for data transmission. Therefore, the timing duration of the timer can be set to be longer to increase the possibility of successful data transmission.

[0125] In some embodiments, the data transmitted on the first link includes multiple QoS flows, and the priority of the data transmitted on the first link may be, for example, the highest priority among the priorities of the multiple QoS flows.

[0126] 33) Link quality of the first link.

[0127] In some embodiments, when the link quality of the first link is good, it can be considered that the probability of the first link being disconnected in a short period of time is small, so in this case the timing duration of the timer can be set to be relatively long.

[0128] 34) The number of relay terminal devices on the first link.

[0129] In some embodiments, the more relay terminal devices there are on the first link (that is, the more relay hops the data transmission passes through), the more unfinished transmission data cached on the first link can be considered. Therefore, in this case, the timing duration of the timer can be set to a relatively large length so that the unfinished transmission data can be transmitted as quickly as possible.

[0130] 35) The congestion level of the resource pool.

[0131] In some embodiments, the higher the congestion level of the resource pool, the longer the data transmission time may be. Therefore, in this case, the timing duration of the timer may be set to be relatively large.

[0132] 36) Resource allocation method.

[0133] In some embodiments, based on the resource allocation method, the number of transmissions required for the unfinished data can be estimated. Therefore, the timing duration of the timer can be set based on the estimated number of transmissions to ensure that the unfinished data is transmitted as quickly as possible.

[0134] In some embodiments, the timing duration of the timer may be configured by the network device, or may be determined by the first device.

[0135] To facilitate understanding of the embodiments of the present application, the following describes a possible implementation of the method shown in FIG4 , with reference to examples. This solution is applicable to both U2N and U2U relay scenarios. In this solution, the remote terminal device / network device can determine whether to disconnect (disconnect the source path) using a timer.

[0136] In the U2N scenario, in a first implementation (denoted as implementation #1), the remote terminal device may determine whether to perform a disconnection operation using a timer. In a second implementation (denoted as implementation #2), the network device may determine whether to perform a disconnection operation using a timer.

[0137] The following introduces the above implementation method #1 and implementation method #2 respectively.

[0138] Implementation #1:

[0139] Exemplarily, the remote terminal device may start the timer when a certain condition (referred to as condition #1) is met. Condition #1 may include, for example, one or more of the following a) to c):

[0140] a) The remote terminal device receives a HO command (such as an RRCReconfiguration message) from the network device. That is, when the remote terminal device receives the HO command from the network device, the remote terminal device may start a timer.

[0141] The RRCReconfiguration message may carry handover-related information, such as an indication of switching from an indirect path to a direct path / indirect path in an intra-gNB handover scenario. Another example of an indication of switching from an indirect path to a direct path / indirect path in an inter-gNB handover scenario is that the RRCReconfiguration message may carry handover-related information, such as an indication of switching from an indirect path to a direct path / indirect path in an inter-gNB handover scenario.

[0142] b) The remote terminal device successfully accesses the network device via the new path, or in other words, the remote terminal device successfully connects to the new path, such as successfully sending an RRCReconfigurationComplete message. In other words, when the remote terminal device successfully accesses the network device via the new path, the remote terminal device may start a timer.

[0143] c) The remote terminal device receives a notification message from the relay terminal device. That is, when the remote terminal device receives the notification message from the relay terminal device, the remote terminal device may start a timer.

[0144] In some embodiments, the remote terminal device may stop sending uplink data on the source path while the timer is running, but may continue receiving downlink data.

[0145] In some embodiments, if the remote terminal device receives downlink data on the source path, the timer can be restarted until the timer times out and no downlink data is received. In this case, it is considered that there is no downlink data cached on the intermediate node (relay terminal device). In this case, the source path can be disconnected, or in other words, the remote terminal device can perform a disconnect operation on the source path.

[0146] Implementation #2:

[0147] Exemplarily, the network device may start the timer when a certain condition (referred to as condition #2) is met. Condition #2 may include, for example, one or more of the following d) to g):

[0148] d) The network device sends a HO command (such as an RRCReconfiguration message) to the remote terminal device. That is, the network device may start a timer when sending the HO command to the remote terminal device.

[0149] The RRCReconfiguration message may carry handover-related information, such as an indication of switching from an indirect path to a direct path / indirect path in an intra-gNB handover scenario. Another example of an indication of switching from an indirect path to a direct path / indirect path in an inter-gNB handover scenario is:

[0150] e) In an intra-gNB handover scenario, the network device receives an RRCReconfigurationComplete message from a remote terminal device. This RRCReconfigurationComplete message may indicate that the remote terminal device has successfully accessed the network device via the new path. In other words, the network device may start a timer when the terminal device has successfully accessed the network device via the new path.

[0151] f) In an inter-gNB handover scenario, the network device receives a Handover Request Accept message from the target gNB. This Handover Request Accept message may indicate that the remote terminal device has successfully connected to the target gNB. In other words, the network device may start a timer when the remote terminal device has successfully connected to the target gNB.

[0152] g) The network device sends an RRCReconfiguration message to at least one relay terminal device, and the RRCReconfiguration message carries handover-related information. That is, the network device may start a timer when sending the RRCReconfiguration message to at least one relay terminal device.

[0153] In some embodiments, the network device may stop sending downlink data on the source path while the timer is running, but may continue receiving uplink data.

[0154] In some embodiments, if the network device receives uplink data on the source path, it can restart the timer until the timer times out and no uplink data is received. In this case, it is considered that there is no uplink data cached on the intermediate node (relay terminal device). In this case, the source path can be disconnected, or the network device can perform a disconnection operation on the source path.

[0155] In the U2U scenario, the remote terminal device (such as one of the remote terminal devices in the U2U scenario) may start a timer when determining to perform relay reselection.

[0156] In some embodiments, the timer duration (timer value) may be configured by the network device, or may be derived by the remote terminal device according to certain rules. For example, the timer duration may be related to one or more of the following information:

[0157] The PDB value of the data transmitted on the source path, such as the maximum value among the PDBs of all QoS flows transmitted on the source path;

[0158] The priority value of the data transmitted on the source path, such as the highest priority among the priorities of the QoS flows transmitted on the source path;

[0159] The link quality measurement value of the source path. If the link quality is good, the timing length of the timer can be set to a longer value.

[0160] The number of relay hops that data transmitted on the source path needs to pass through. The greater the number of hops, the longer the timer duration can be set.

[0161] The congestion level of the resource pool. If the congestion level is higher, the timer duration can be set longer.

[0162] Resource allocation method.

[0163] According to the method of this embodiment, the remote terminal device / network device can continue to maintain the source connection for a period of time when the state of the source path changes or is about to change. In this way, the data cached on the intermediate node (relay terminal device) can be transmitted as much as possible before the source path is disconnected to avoid data loss.

[0164] Another communication method provided in an embodiment of the present application is described below in conjunction with FIG5 .

[0165] FIG5 is a second flow diagram of a communication method provided by an embodiment of the present application. In this method, the first link where the third device and the fourth device are located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device. As shown in FIG5 , the method may include the following steps:

[0166] S501: A third device sends first information to a fourth device on a first link. The first information is used to determine whether there is any uncompleted transmission data on the first link.

[0167] Accordingly, the fourth device may receive the first information from the third device on the first link.

[0168] In this embodiment, the first information can be used to determine whether there is uncompleted transmission data on the first link. Taking the example of a remote terminal device sending data to a target device, uncompleted transmission data can also be understood as data sent by the remote terminal device but not received by the target device; taking the example of a target device sending data to a remote terminal device, uncompleted transmission data can also be understood as data sent by the target device but not received by the remote terminal device.

[0169] According to the method of this embodiment, after receiving the first information, the fourth device can learn whether there is any uncompleted transmitted data on the first link based on the first information, thereby helping the fourth device to take measures to avoid loss of the uncompleted transmitted data.

[0170] In some embodiments, the third device may be a first relay terminal device on the first link. In this case, the first information may include: seventh indication information indicating the amount of data to be sent by the first relay terminal device; and / or eighth indication information indicating whether the first relay terminal device has cached data to be sent. The first relay terminal device may be, for example, any relay terminal device on the first link.

[0171] In some embodiments, the seventh indication information may include, for example, the data volume of the data to be sent by the first relay terminal device (such as the data volume included in the RLC layer of the first relay terminal device) and the identification (ID) of the remote terminal device. The identification of the remote terminal device may be used to indicate that the data to be sent by the first relay terminal device is associated with the remote terminal device.

[0172] The data to be sent by the first relay terminal device is associated with the remote terminal device, which may include: the data to be sent is data to be sent to the remote terminal device; and / or the data to be sent is data from the remote terminal device. That is, in some embodiments, if the data to be sent by the first relay terminal device is to be sent to the remote terminal device, and / or if the data to be sent by the first relay terminal device is from the remote terminal device, the first relay terminal device may carry the data volume of the data to be sent and the identifier of the remote terminal device in the seventh indication information.

[0173] In some embodiments, the seventh indication information may further include: an index of a logical channel or an index of a logical channel group. The index of a logical channel may be used to indicate that data to be sent by the first relay terminal device is associated with the logical channel; the index of a logical channel group may be used to indicate that data to be sent by the first relay terminal device is associated with the logical channel group.

[0174] The data to be sent by the first relay terminal device is associated with a logical channel, which may include: the data to be sent by the first relay terminal device will be sent through the logical channel, and / or the data to be sent by the first relay terminal device comes from the logical channel. That is to say, in some embodiments, if the data to be sent by the first relay terminal device will be sent through the logical channel, and / or if the data to be sent by the first relay terminal device comes from the logical channel, the first relay terminal device may also carry the index of the logical channel in the seventh indication information.

[0175] The data to be sent by the first relay terminal device is associated with the logical channel group, which may include: the data to be sent by the first relay terminal device will be sent through the logical channel group, and / or the data to be sent by the first relay terminal device comes from the logical channel group. That is to say, in some embodiments, if the data to be sent by the first relay terminal device will be sent through the logical channel group, and / or if the data to be sent by the first relay terminal device comes from the logical channel group, the first relay terminal device may also carry the index of the logical channel group in the seventh indication information.

[0176] In some embodiments, the eighth indication information may include, for example: a first parameter; and / or an identifier of the remote terminal device, wherein the first parameter may be used to indicate whether the first relay terminal device buffers data to be sent.

[0177] In some embodiments, when the eighth indication information includes a first parameter, and the first parameter indicates that the first relay terminal device caches data to be sent, the identifier of the remote terminal device can be used to indicate that the data to be sent is associated with the remote terminal device.

[0178] The data to be sent is associated with the remote terminal device, which can be understood as follows: the data to be sent is data to be sent to the remote terminal device; and / or the data to be sent is data from the remote terminal device. That is, in some embodiments, if the data to be sent cached by the first relay terminal device is to be sent to the remote terminal device, and / or if the data to be sent cached by the first relay terminal device is from the remote terminal device, the first relay terminal device may carry the first parameter and the identifier of the remote terminal device in the eighth indication information.

[0179] In some embodiments, when the eighth indication information does not include the first parameter, the identifier of the remote terminal device can be used to indicate that the first relay terminal device caches data to be sent, and the data to be sent is associated with the remote terminal device.

[0180] In some embodiments, the eighth indication information includes an identifier of the remote terminal device, and also includes: an index of a logical channel or an index of a logical channel group; when the first relay terminal device caches data to be sent, the index of the logical channel can be used to indicate that the data to be sent is associated with the logical channel; the index of the logical channel group can be used to indicate that the data to be sent is associated with the logical channel group.

[0181] The data to be sent is associated with the logical channel, which may include: the data to be sent will be sent through the logical channel, and / or the data to be sent comes from the logical channel. That is to say, in some embodiments, if the data to be sent cached by the first relay terminal device will be sent through the logical channel, and / or if the data to be sent cached by the first relay terminal device comes from the logical channel, the first relay terminal device may also carry the index of the logical channel in the eighth indication information.

[0182] The data to be sent is associated with the logical channel group, which may include: the data to be sent will be sent through the logical channel group, and / or the data to be sent comes from the logical channel group. That is to say, in some embodiments, if the data to be sent cached by the first relay terminal device will be sent through the logical channel group, and / or if the data to be sent cached by the first relay terminal device comes from the logical channel group, the first relay terminal device may also carry the index of the logical channel group in the eighth indication information.

[0183] In some embodiments, when the third device is the first relay terminal device on the first link, the fourth device may be: a remote terminal device; or a target device; or a relay terminal device adjacent to the first relay terminal device on the first link.

[0184] In one example, the fourth device is a remote terminal device. In this case, after receiving the first information from the first relay terminal device, the remote terminal device may, for example, learn that the first relay terminal device has cached data to be sent to the remote terminal device. In this case, to avoid data loss, the remote terminal device may maintain a connection with the first relay terminal device. For example, in a scenario where the remote terminal device is switching, if the remote terminal device learns based on the first information that the first relay terminal device has cached data to be sent to the remote terminal device, the remote terminal device may maintain a connection with the first relay terminal device for a period of time and then disconnect it, so that the first relay terminal device can successfully send the data to be sent to the remote terminal device within this period of time.

[0185] In another example, the fourth device is the target device. In this case, after receiving the first information from the first relay terminal device, the target device may learn that the first relay terminal device has cached data to be sent to the remote terminal device, or may learn that the first relay terminal device has cached data from the remote terminal device. In this case, if the target device learns based on the first information that the first relay terminal device has cached data to be sent to the remote terminal device, the target device may instruct the remote terminal device to maintain the connection with the first relay terminal device for a period of time before disconnecting, so that the first relay terminal device can successfully send the data to be sent to the remote terminal device within the period; if the target device learns based on the first information that the first relay terminal device has cached data from the remote terminal device, the target device may maintain the connection with the first relay terminal device for a period of time before disconnecting, so that the first relay terminal device can successfully send the data from the remote terminal device to the target device within the period.

[0186] In another example, the fourth device is a relay terminal device adjacent to the first relay terminal device on the first link (e.g., an adjacent relay terminal device). In this case, after receiving the first information from the first relay terminal device, the adjacent relay terminal device may learn that the first relay terminal device has cached data to be sent to the remote terminal device, or may learn that the first relay terminal device has cached data from the remote terminal device. In this case, the adjacent relay terminal device may maintain a connection with the first relay terminal device to enable normal transmission of the data cached by the first relay terminal device.

[0187] In some embodiments, the third device may be a remote terminal device and the fourth device may be a target device. In this case, the first information may include: ninth indication information, which may be used to indicate: data that the remote terminal device has sent to the target device, and / or data that the remote terminal device has received from the target device.

[0188] In some embodiments, when the ninth indication information is used to indicate data that the remote terminal device has sent to the target device, the ninth indication information may include: an index of the data that the remote terminal device has sent to the target device (such as a PDCP sequence number (SN)); when the ninth indication information is used to indicate data that the remote terminal device has received from the target device, the ninth indication information may include: an index of the data that the remote terminal device has received from the target device (such as a PDCP SN).

[0189] According to the method of this embodiment, after receiving the first information from the remote terminal device, the target device can obtain data that the remote terminal device has sent to the target device and / or data that the remote terminal device has received from the target device. If the target device obtains data that the remote terminal device has sent to the target device, the target device can infer data that the remote terminal device has sent but the target device has not received. In this case, the target device can instruct the remote terminal device to retransmit the data that the target device has not received to avoid data loss. If the target device obtains data that the remote terminal device has received from the target device, the target device can infer data that the target device has sent but the remote terminal device has not received. In this case, the target device can retransmit the data that the remote terminal device has not received to avoid data loss.

[0190] In some embodiments, the third device may be a target device and the fourth device may be a remote terminal device. In this case, the first information may include: tenth indication information, which may be used to indicate: data that the target device has sent to the remote terminal device, and / or data that the target device has received from the remote terminal device.

[0191] In some embodiments, when the tenth indication information is used to indicate data that the target device has sent to a remote terminal device, the tenth indication information may include: an index of the data that the target device has sent to the remote terminal device (such as a PDCP SN); when the tenth indication information is used to indicate data that the target device has received from a remote terminal device, the tenth indication information may include: an index of the data that the target device has received from the remote terminal device (such as a PDCP SN).

[0192] According to the method of this embodiment, after receiving the first information from the target device, the remote terminal device can obtain data that the target device has sent to the remote terminal device and / or data that the target device has received from the remote terminal device. If the remote terminal device obtains data that the target device has sent to the remote terminal device, the remote terminal device can infer data that the target device has sent but the remote terminal device has not received. In this case, the remote terminal device can instruct the target device to retransmit the data that the remote terminal device has not received to avoid data loss. If the remote terminal device obtains data that the target device has received from the remote terminal device, the remote terminal device can infer data that the remote terminal device has sent but the target device has not received. In this case, the remote terminal device can retransmit the data that the target device has not received to avoid data loss.

[0193] In some embodiments, the first information is sent by the third device to the fourth device upon receiving the request information.

[0194] As an example, if the third device is a remote terminal device, the request information may come from the target device. That is, the target device may send the request information to the remote terminal device, and the remote terminal device may receive the request information. Furthermore, the remote terminal device may send the first information to the fourth device (e.g., the target device) in response to the request information.

[0195] As another example, if the third device is the first relay terminal device on the first link, the request information may come from, for example, a remote terminal device or a target device. That is, the remote terminal device or the target device may send the request information to the first relay terminal device, and the first relay terminal device may receive the request information. Furthermore, the first relay terminal device may send the first information to the fourth device (e.g., the remote terminal device or the target device) in response to the request information.

[0196] As another example, when the third device is the target device, the request information may come from a remote terminal device. That is, the remote terminal device may send the request information to the target device, and the target device may receive the request information. Furthermore, the target device may send the first information to the fourth device (e.g., the remote terminal device) in response to the request information.

[0197] In some embodiments, for the fourth device, before the fourth device receives the first information from the third device on the first link, the method may further include: the fourth device sending request information to the third device, where the request information is used to request the first information.

[0198] As an example, when the fourth device is a remote terminal device, the third device may be, for example, a target device or a first relay terminal device on the first link. In other words, the remote terminal device may send a request message to the target device or the first relay terminal device to request the first information.

[0199] As another example, when the fourth device is the target device, the third device may be, for example, a remote terminal device or a first relay terminal device on the first link. In other words, the target device may send a request message to the remote terminal device or the first relay terminal device to request the first information.

[0200] In some embodiments, when the fourth device is a remote terminal device, the request information may be sent by the remote terminal device to the third device when the fourth condition is met.

[0201] As an example, the fourth condition may include one or more of the following 41) to 43):

[0202] 41) The remote terminal device receives a first switching command from the network device, where the first switching command is used to instruct the remote terminal device to switch from the first link to another link;

[0203] 42) The link quality between the remote terminal device and the second relay terminal device is lower than the first threshold, and the second relay terminal device is a relay terminal device directly connected to the remote terminal device on the first link;

[0204] 43) The remote terminal device receives thirteenth indication information from the third relay terminal device on the first link, where the thirteenth indication information is used to indicate that a link status change occurs between the third relay terminal device and an adjacent device on the first link.

[0205] The third relay terminal device may be, for example, any relay terminal device on the first link.

[0206] In some embodiments, a link state change between the third relay terminal device and the adjacent device on the first link may include any of the following:

[0207] A wireless link failure occurs in the link between the third relay terminal device and the adjacent device; the link quality between the third relay terminal device and the adjacent device is lower than a first threshold; a link switch occurs in the third relay terminal device; a cell switch occurs in the third relay terminal device.

[0208] Among them, the link between the third relay terminal device and the adjacent device can be, for example, a Uu link or a PC5 link. Taking the communication scenario shown in Figure 3 as an example, if the third relay terminal device is relay terminal device #1, then the link between relay terminal device #1 and the adjacent device can be, for example, a PC5 link between relay terminal device #1 and the remote terminal device, or can be a PC5 link between relay terminal device #1 and relay terminal device #2. If the third relay terminal device is relay terminal device #2, then the link between relay terminal device #2 and the adjacent device can be, for example, a PC5 link between relay terminal device #2 and relay terminal device #1, or can be a Uu link between relay terminal device #2 and the target device (assuming the target device is a network device).

[0209] According to the method of this embodiment, if the fourth condition is met, it can be indicated that the state of the first link has changed or is about to change, or that there is a risk of data loss due to disconnection of the first link. Therefore, if the fourth condition is met, the fourth device (remote terminal device) can send a request message to the third device to request the first information. This first information helps the fourth device take measures to avoid the loss of the unfinished data.

[0210] In some embodiments, when the fourth device is a target device and the target device is a network device, the request information may be sent by the network device to the third device when a fifth condition is met.

[0211] As an example, the fifth condition may include: the network device sends a first switching command to the remote terminal device, the first switching command is used to instruct the remote terminal device to switch from the first link to other links; and / or, the network device sends a second switching command to at least one relay terminal device on the first link, the second switching command sent to the relay terminal device is used to instruct the relay terminal device to perform link switching.

[0212] In some scenarios, the network device sends a first switching command to the remote terminal device, which may include the situation before the network device sends the first switching command to the remote terminal device, for example, the network device has determined / decided to send the first switching command to the remote terminal device but has not yet sent the first switching command; in some scenarios, the network device sends a first switching command to the remote terminal device, which may also include the situation when the network device sends the first switching command to the remote terminal device, or has already sent the first switching command to the remote terminal device.

[0213] In some scenarios, the network device sends a second switching command to at least one relay terminal device on the first link, which may include the situation before the network device sends the second switching command to the at least one relay terminal device, for example, the network device has determined / decided to send the second switching command to the at least one relay terminal device but has not yet sent the second switching command; in some scenarios, the network device sends a second switching command to at least one relay terminal device on the first link, which may also include the situation when the network device sends the second switching command to the at least one relay terminal device, or has already sent the second switching command to the at least one relay terminal device.

[0214] In some embodiments, the request information may include an identifier of the remote terminal device. Thus, after receiving the request information, the third device may send the first information associated with the remote terminal device to the fourth device based on the identifier of the remote terminal device carried in the request information.

[0215] For example, based on the identifier of the remote terminal device carried in the request message, the third device (e.g., the first relay terminal device) may include in the seventh indication information: the amount of data to be sent by the first relay terminal device and the identifier of the remote terminal device. For another example, based on the identifier of the remote terminal device carried in the request message, the third device (e.g., the first relay terminal device) may include in the eighth indication information: the first parameter and the identifier of the remote terminal device; or the identifier of the remote terminal device. For another example, based on the identifier of the remote terminal device carried in the request message (i.e., the identifier of the third device), the third device (e.g., the remote terminal device) may send ninth indication information to the fourth device to indicate data that the remote terminal device has sent to the target device and / or data that the remote terminal device has received from the target device. For another example, based on the identifier of the remote terminal device carried in the request message, the third device (e.g., the target device) may send tenth indication information to the fourth device to indicate data that the target device has sent to the remote terminal device and / or data that the target device has received from the remote terminal device.

[0216] In some embodiments, the request information may further include an index of a logical channel or an index of a logical channel group. Thus, upon receiving the request information, the third device may, based on the index of the logical channel or the index of the logical channel group carried in the request information, send the first information associated with the index of the logical channel or the index of the logical channel group to the fourth device.

[0217] For example, the third device (such as the first relay terminal device) may further carry, in the seventh indication information, the index of the logical channel or the index of the logical channel group carried in the request information. For another example, the third device (such as the first relay terminal device) may further carry, in the eighth indication information, the index of the logical channel or the index of the logical channel group carried in the request information.

[0218] In some embodiments, the period for the third device to send the first information to the fourth device is the first time interval. That is, the third device can use the first time interval as a sending period to periodically send the first information to the fourth device.

[0219] In some embodiments, the first time interval is configured by the network device; or, the first time interval is preconfigured; or, the first time interval is configured by any relay terminal device on the first link; or, the first time interval is configured by a remote terminal device.

[0220] In some implementations, the first time interval can be associated with one or more of the following information 51) to 54):

[0221] 51) The number of relay terminal devices on the first link.

[0222] In some embodiments, the more relay terminal devices there are on the first link (that is, the more relay hops the data transmission passes through), the higher the probability that there is unfinished transmission data on the first link. Therefore, in this case, the first time interval can be set to a relatively small value so that the third device sends the first information to the fourth device more frequently, thereby reducing the risk of data loss.

[0223] 52) The priority of the data transmitted on the first link.

[0224] In some embodiments, the higher the priority of the data, the higher the reliability requirement for data transmission can be considered. Therefore, the first time interval can be set relatively small so that the third device sends the first information to the fourth device more frequently, thereby reducing the risk of data loss.

[0225] 53) The congestion level of the resource pool.

[0226] In some embodiments, the higher the congestion level of the resource pool, the higher the probability that there is uncompleted transmission data on the first link. Therefore, in this case, the first time interval can be set to be relatively small so that the third device sends the first information to the fourth device more frequently, thereby reducing the risk of data loss.

[0227] 54)QoS parameters.

[0228] As an example, the QoS parameters may include: a packet error rate (PER) and / or a PDB of data transmitted on the first link.

[0229] In some embodiments, a smaller PER indicates a higher reliability requirement for data transmission. Therefore, the first time interval may be set to be relatively small so that the third device sends the first information to the fourth device more frequently, thereby reducing the risk of data loss.

[0230] In some embodiments, since data exceeding the PDB is invalid during data transmission, the first time interval may be smaller than the PDB.

[0231] In some embodiments, when the third device is a remote terminal device, the first information may be sent by the remote terminal device to the fourth device when the first condition is met.

[0232] As an example, the first condition may include one or more of the following:

[0233] The remote terminal device receives a first switching command from the network device, where the first switching command may be used to instruct the remote terminal device to switch from the first link to another link;

[0234] The link quality between the remote terminal device and the second relay terminal device is lower than the first threshold, and the second relay terminal device is a relay terminal device directly connected to the remote terminal device on the first link;

[0235] The remote terminal device receives eleventh indication information from the first relay terminal device on the first link, where the eleventh indication information is used to indicate that a link status change occurs between the first relay terminal device and an adjacent device on the first link.

[0236] The first relay terminal device may be, for example, any relay terminal device on the first link.

[0237] In some embodiments, a state change occurs in the link between the first relay terminal device and the adjacent device on the first link, which may include any of the following: a wireless link failure occurs in the link between the first relay terminal device and the adjacent device; the link quality between the first relay terminal device and the adjacent device is lower than a first threshold; a link switch occurs in the first relay terminal device; a cell switch occurs in the first relay terminal device.

[0238] The link between the first relay terminal device and the adjacent device may be, for example, a Uu link or a PC5 link.

[0239] According to the method of this embodiment, if the first condition is met, it can be indicated that the state of the first link has changed or is about to change, or that there is a risk of data loss due to disconnection of the first link. Therefore, if the first condition is met, the third device (remote terminal device) can send the first information to the fourth device. This first information helps the fourth device take measures to avoid the loss of the unfinished data.

[0240] In some embodiments, when the third device is the first relay terminal device on the first link, the first information may be sent by the first relay terminal device to the fourth device when the second condition is met.

[0241] As an example, the second condition may include: a state change occurs in the link between the first relay terminal device and the adjacent device on the first link; and / or the first relay terminal device receives twelfth indication information from the target device, and the twelfth indication information is used to indicate the release of the connection between the first relay terminal device and the target device.

[0242] The first relay terminal device may be, for example, any relay terminal device on the first link.

[0243] In some embodiments, a state change occurs in the link between the first relay terminal device and the adjacent device on the first link, which may include any of the following: a wireless link failure occurs in the link between the first relay terminal device and the adjacent device; the link quality between the first relay terminal device and the adjacent device is lower than a first threshold; a link switch occurs in the first relay terminal device; a cell switch occurs in the first relay terminal device.

[0244] According to the method of this embodiment, if the first condition is met, it can be indicated that the state of the first link has changed or is about to change, or that there is a risk of data loss due to disconnection of the first link. Therefore, if the first condition is met, the third device (the first relay terminal device) can send the first information to the fourth device. This first information helps the fourth device take measures to avoid the loss of the unfinished data.

[0245] In some embodiments, when the third device is a target device and the target device is a network device, the first information may be sent by the network device to the fourth device when the third condition is met.

[0246] As an example, the third condition may include: the network device sends a first switching command to the remote terminal device; and / or the network device sends a second switching command to at least one relay terminal device on the first link.

[0247] The first switching command is used to instruct the remote terminal device to switch from the first link to another link; the second switching command sent to the relay terminal device is used to instruct the relay terminal device to perform link switching.

[0248] In some scenarios, the network device sends a first switching command to the remote terminal device, which may include the situation before the network device sends the first switching command to the remote terminal device, that is, the network device has determined / decided to send the first switching command to the remote terminal device but has not yet sent the first switching command; in some scenarios, the network device sends the first switching command to the remote terminal device, which may also include the situation when the network device sends the first switching command to the remote terminal device, or has already sent the first switching command to the remote terminal device.

[0249] In some scenarios, the network device sends a second switching command to at least one relay terminal device on the first link, which may include the situation before the network device sends the second switching command to the at least one relay terminal device, that is, the network device has determined / decided to send the second switching command to the at least one relay terminal device but has not yet sent the second switching command; in some scenarios, the network device sends a second switching command to at least one relay terminal device on the first link, which may also include the situation when the network device sends the second switching command to the at least one relay terminal device, or has already sent the second switching command to the at least one relay terminal device.

[0250] In some embodiments, the first information can be carried, for example, by one of the following information: RRC signaling; PDCP status report (Status Report, SR); Media Access Control (Media Access Control, MAC) control element (MAC Control Element, MAC CE); RLC control protocol data unit (Protocol Data Unit, PDU); SRAP control PDU.

[0251] In some embodiments, the target device in the embodiments of the present application may be a network device or a terminal device (such as another remote terminal device).

[0252] To facilitate understanding of the embodiments of the present application, the following describes a possible implementation of the method shown in Figure 5 with reference to examples. This solution is applicable to U2N relay scenarios or U2U relay scenarios, and the following uses the U2N relay scenario as an example for exemplary description.

[0253] In this solution, the data transmission status between the remote terminal device and the network device can be determined by transmitting data status information (corresponding to the first information in the method shown in FIG. 5 ).

[0254] In some embodiments, the transmission of the data status information includes, for example, the following situations:

[0255] Transmitted from a relay terminal device (relay node) to a remote terminal device (for example, transmitted from each relay terminal device to a remote terminal device; for another example, transmitted from a relay terminal device closest to the other end to the remote terminal device);

[0256] Transmitted from one relay terminal device to another relay terminal device (for example, transmitted from one relay terminal device to a relay terminal device adjacent to the relay terminal device);

[0257] Transmitted from the relay terminal device to the network device (for example, it may be transmitted from each relay terminal device to the network device; for another example, it may be transmitted from the relay terminal device closest to the other end to the network device);

[0258] Transmit from remote terminal device to network device;

[0259] Transmitted from network equipment to remote terminal equipment.

[0260] In some embodiments, the data status information may be carried in one of the following information: RRC signaling; PDCP SR; MAC CE; RLC control PDU; SRAP control PDU.

[0261] In some embodiments, the data status information may include one or more of the following information: data volume information (corresponding to the seventh indication information in the aforementioned embodiment); data transmission status information (corresponding to the ninth indication information / tenth indication information in the aforementioned embodiment); and indication information indicating that the current device still has unsent data buffered (corresponding to the eighth indication information in the aforementioned embodiment). Each of these information items is described below.

[0262] Data volume information:

[0263] Exemplarily, the data volume information may be carried in the data status information transmitted from the relay terminal device to the remote terminal device, or may be carried in the data status information transmitted from the relay terminal device to the network device, or may be carried in the data status information transmitted from one relay terminal device to another relay terminal device.

[0264] The data volume information may include, for example, the data volume included in the RLC layer.

[0265] It should be noted that in the current SL mode-2 resource acquisition method, the RLC layer does not include data volume. Therefore, a new data volume calculation purpose (e.g., calculating the data volume for data status information in a relay scenario) needs to be introduced to obtain the data volume of the RLC layer.

[0266] In some embodiments, the data volume may be, for example, the data volume associated with a single remote terminal device (per-remote-UE). For example, in the U2N relay scenario of this embodiment, the data volume may include: the data volume associated with the remote terminal device in the U2N relay scenario. In this case, the data volume information may also include: the ID of the remote terminal device associated with the data volume (such as L2ID or local UE ID).

[0267] In some embodiments, the data volume may be, for example, the data volume associated with each LCH (per-remote UE per LCH) of a single remote terminal device. For example, in the U2N relay scenario of this embodiment, the data volume may include: the data volume associated with each LCH of the remote terminal device in the U2N relay scenario. In this case, the data volume information may also include: the ID of the remote terminal device associated with the data volume (such as L2ID or local UE ID) and the index of the LCH (such as LCH on a Uu or PC5 link).

[0268] In some embodiments, the data volume may be, for example, the data volume associated with each LCG (per-remote UE per LCG) of a single remote terminal device. For example, in the U2N relay scenario of this embodiment, the data volume may include: the data volume associated with each LCG of the remote terminal device in the U2N relay scenario. In this case, the data volume information may also include: the ID of the remote terminal device associated with the data volume (such as L2ID or local UE ID) and the index of the LCG (such as an LCG on a Uu or PC5 link).

[0269] Data sending status information:

[0270] Exemplarily, the data sending status information may be carried in data status information transmitted from the remote terminal device to the network device, or may be carried in data status information transmitted from the network device to the remote terminal device.

[0271] The data transmission status information may include, for example, a status identifier of data currently transmitted / received by the current device (the device generating the data status information), such as a PDCP SN number.

[0272] Indicates that the device currently has buffered data that has not yet been sent.

[0273] In one possible implementation, the indication information may, for example, indicate whether the current device (the device generating the data status information) has any unsent data cached. For example, the indication information may include a first parameter that may be used to indicate whether the current device has any unsent data cached.

[0274] In another possible implementation, the indication information may, for example, implicitly indicate whether the current device has cached unsent data. For example, the indication information may include the ID of the remote terminal device (such as L2ID or local UE ID), and the ID of the remote terminal device may be used to indicate that the current device has cached unsent data, and the unsent data is associated with the remote terminal device. In some embodiments, the indication information may also include the index of the LCH or the index of the LCG. The index of the LCH may be used to indicate that the unsent data is associated with the LCH; the index of the LCG may be used to indicate that the unsent data is associated with the LCG.

[0275] In another possible implementation, the indication information may include both the first parameter and the ID of the remote terminal device. In this case, if the first parameter indicates that the current device cache has unsent data, the ID of the remote terminal device may be used to indicate that the unsent data is associated with the remote terminal device. In some embodiments, the indication information may also include an LCH index or an LCG index. If the first parameter indicates that the current device cache has unsent data, the LCH index may be used to indicate that the unsent data is associated with the LCH; the LCG index may be used to indicate that the unsent data is associated with the LCG.

[0276] In some embodiments, the triggering condition for the data status information may be: based on a request trigger. For example, if a data status information request message (corresponding to the request message in the aforementioned embodiment) is received, the data status information is sent. Exemplarily, the request message may come from a remote terminal device and / or a network device, and the request message may include: ID information of the remote terminal device associated with the requested data status information; LCH information associated with the requested data status information (such as an LCH index); and LCG information associated with the requested data status information (such as an LCG index).

[0277] In some embodiments, the remote terminal device may trigger the sending of the request information when one or more of the following conditions are met:

[0278] 1) The remote terminal device receives a switching command from the network;

[0279] 2) The remote terminal device receives PC5-RRC / PC5-S signaling from the relay terminal device indicating that the Uu / PC5 link of the relay has changed / changed in status (such as HO, cell reselection, RLF, link quality is lower than a certain threshold, etc.);

[0280] 3) The PC5 link quality between the remote terminal device and the relay terminal device is lower than a certain threshold (eg, lower than a first threshold).

[0281] In some embodiments, the network device may trigger the sending of the request information when one or more of the following conditions are met:

[0282] 1) When the network device sends a switching command to the remote terminal device or before sending a switching command;

[0283] 2) When the network device sends a switching command to at least one relay terminal device or before sending the switching command.

[0284] In some embodiments, the triggering condition for the data status information may be periodic triggering. For example, the triggering period may be network-configured, pre-configured, configured by the relay terminal device, or configured by the remote terminal device. In some embodiments, the period may be related to the number of relay hops, data transmission priority, resource pool congestion level, QoS parameters (e.g., PDB, PER), etc.

[0285] In some embodiments, the triggering condition of the data status information may be: based on an event trigger.

[0286] Exemplarily, the event that triggers the remote terminal device to send data status information may include one or more of the following:

[0287] 1) The remote terminal device receives a switching command from the network;

[0288] 2) The remote terminal device receives PC5-RRC / PC5-S signaling from the relay terminal device indicating that the Uu / PC5 link of the relay has changed / changed in status (such as HO, cell reselection, RLF, link quality is lower than a certain threshold, etc.);

[0289] 3) The PC5 link quality between the remote terminal device and the relay terminal device is lower than a certain threshold (eg, lower than a first threshold).

[0290] Exemplarily, the event that triggers the relay terminal device to send data status information may include one or more of the following:

[0291] 1) The Uu link of the relay terminal device changes / changes in status (such as Uu RLF, HO, cell reselection, link quality below a certain threshold, etc.);

[0292] 2) The relay terminal device receives a connection release message from the network device;

[0293] 3) The PC5 link of the relay terminal device changes / changes in state (such as RLF, link quality falls below a certain threshold, PC5 connection is released).

[0294] Exemplarily, the event that triggers the network device to send data status information may include one or more of the following:

[0295] 1) When the network device sends a switching command to the remote terminal device or before sending a switching command;

[0296] 2) When the network device sends a switching command to at least one relay terminal device or before sending the switching command.

[0297] In some embodiments, if the data status information is PDCP or RRC layer signaling, it may be sent in an end-to-end manner, that is, the entity (device) generating the data status information directly sends it to the target entity.

[0298] In some embodiments, if the data status information is RLC / SRAP / MAC layer signaling, a hop-to-hop forwarding method may be used, that is, the entity generating the data status information sends it to the intermediate node, and the intermediate node then forwards the data status information. For example, the intermediate node may forward the data status information based on one of the following methods:

[0299] 1) Forward directly without processing.

[0300] 2) Modify the packet header before forwarding. For example, modify the ID information (such as source / destination end) and data identification information (such as logical channel identifier) ​​in the packet header before forwarding.

[0301] 3) Further integration and forwarding. For example, after receiving data status information from the previous hop device, the current device can integrate the data status information from the previous hop device and the data status information generated by the current device into a signaling, and then send the integrated signaling to the next hop device.

[0302] Another communication method provided in an embodiment of the present application is described below in conjunction with FIG6 .

[0303] FIG6 is a flow chart of a communication method according to an embodiment of the present application. In this method, a fourth relay terminal device is located on a first link between a first remote terminal device and a target device, and one or more relay terminal devices exist on the first link. As shown in FIG6 , the method may include the following steps:

[0304] S601: Upon receiving a first positive acknowledgement (ACK) from a fifth device on a first link, the fourth relay terminal device sends a second ACK to a sixth device on the first link.

[0305] Among them, the fifth device is the next-hop device of the fourth relay terminal device in the data transmission direction, and the sixth device is the previous-hop device of the fourth relay terminal device in the data transmission direction; the first ACK is used to indicate that the fifth device has successfully received the first data from the fourth relay terminal device; the second ACK is used to indicate that the fourth relay terminal device has successfully received the first data from the sixth device.

[0306] Taking the communication scenario shown in FIG3 as an example, the first remote terminal device may be the remote terminal device in FIG3 , and the target device may be the target device in FIG3 .

[0307] As an example, the fourth relay terminal device can be the relay terminal device #1 in Figure 3. In this case, if the data transmission direction is from the remote terminal device (the first remote terminal device) to the target device, the fifth device (the next-hop device of the fourth relay terminal device in the data transmission direction) is the relay terminal device #2, and the sixth device (the previous-hop device of the fourth relay terminal device in the data transmission direction) is the remote terminal device; if the data transmission direction is from the target device to the remote terminal device (the first remote terminal device), the fifth device (the next-hop device of the fourth relay terminal device in the data transmission direction) is the remote terminal device, and the sixth device (the previous-hop device of the fourth relay terminal device in the data transmission direction) is the relay terminal device #2.

[0308] As another example, the fourth relay terminal device can be the relay terminal device #2 in Figure 3. In this case, if the data transmission direction is from the remote terminal device (the first remote terminal device) to the target device, the fifth device (the next-hop device of the fourth relay terminal device in the data transmission direction) is the target device, and the sixth device (the previous-hop device of the fourth relay terminal device in the data transmission direction) is the relay terminal device #1; if the data transmission direction is from the target device to the remote terminal device (the first remote terminal device), the fifth device (the next-hop device of the fourth relay terminal device in the data transmission direction) is the relay terminal device #1, and the sixth device (the previous-hop device of the fourth relay terminal device in the data transmission direction) is the target device.

[0309] In some embodiments, before the fourth relay terminal device sends the second ACK to the sixth device on the first link, the method may further include: the fourth relay terminal device receives the first data from the sixth device and sends the first data to the fifth device.

[0310] In other words, the first data can be transmitted from the sixth device to the fourth relay terminal device, which can then forward it to the fifth device. Furthermore, if the fourth relay terminal device receives the first ACK from the fifth device, it can feed back a second ACK to the sixth device. In this way, upon receiving the second ACK from the fourth relay terminal device, the sixth device will know that the first data has been successfully transmitted to the fifth device, thereby ensuring the reliability and continuity of the first data during transmission and avoiding loss of the first data.

[0311] For ease of explanation, the feedback manner in which the fourth relay terminal device sends the second ACK to the sixth device upon receiving the first ACK from the fifth device is referred to as the first feedback mode below.

[0312] In some embodiments, the method may further include: when the fourth relay terminal device receives a negative acknowledgment (NACK) from the fifth device, the fourth relay terminal device retransmitting the first data to the fifth device, wherein the NACK from the fifth device is used to indicate that the fifth device did not successfully receive the first data from the fourth relay terminal device.

[0313] That is, if the fourth relay terminal device receives a NACK from the fifth device, the fourth relay terminal device may retransmit the first data to the fifth device. If the retransmission is successful and the first ACK is received from the fifth device, the second ACK may be fed back to the sixth device.

[0314] In some embodiments, the maximum number of retransmissions of the first data by the fourth relay terminal device to the fifth device may be less than or equal to the first value, and the maximum number of retransmissions may be configured by the network device, for example.

[0315] Since the above technical solution increases the transmission reliability of the first data while also increasing the transmission delay of the first data to a certain extent, the transmission delay of the first data can be reduced by limiting the maximum number of retransmissions of the first data to within the first value.

[0316] In some embodiments, the fourth relay terminal device sends a second ACK to the sixth device on the first link upon receiving the first ACK from the fifth device on the first link, including: if the first condition is met, the fourth relay terminal device sends the second ACK to the sixth device upon receiving the first ACK from the fifth device; the first condition includes: allowing the first data to be transmitted using the first feedback mode, and the first feedback mode for the first data is activated.

[0317] Since the above technical solution increases the transmission reliability of the first data while also increasing the transmission delay of the first data to a certain extent, conditional restrictions can be imposed on the transmission of the first data using the above technical solution (first feedback mode). For example, if the first condition is met, the first feedback mode can be used to transmit the first data, that is, if the first condition is met, the fourth relay terminal device can send a second ACK to the sixth device when it receives the first ACK from the fifth device. Correspondingly, if the first condition is not met, it is not necessary to use the first feedback mode to transmit the first data, that is, if the first condition is not met, the fourth relay terminal device does not need to send the second ACK to the sixth device when it receives the first ACK from the fifth device, but can use a general feedback method (that is, if the fourth relay terminal device successfully receives the first data from the sixth device, it can send the second ACK to the sixth device) to transmit the first data to reduce the transmission delay of the first data.

[0318] In some embodiments, when the target device is a network device, whether the first feedback mode is allowed to be used to transmit the first data can be determined based on first information from the network device; whether the first feedback mode for the first data is activated can be determined based on second information from the network device or the first remote terminal device.

[0319] In some embodiments, when the target device is a second remote terminal device, whether the first feedback mode is allowed to be used to transmit the first data can be determined based on first information from the network device; whether the first feedback mode for the first data is activated can be determined based on second information from the first remote terminal device or the second remote terminal device.

[0320] According to the method of this embodiment, whether the first data is allowed to be transmitted using the first feedback mode can be determined / configured using the first information, and whether the first feedback mode for the first data is activated can be further determined / configured using the second information. Furthermore, if the first data is determined / configured to allow transmission using the first feedback mode, and the first feedback mode for the first data is activated, the fourth relay terminal device can transmit the first data using the first feedback mode. That is, upon receiving the first ACK from the fifth device, the fourth relay terminal device can send a second ACK to the sixth device.

[0321] In some embodiments, the first information may be, for example, an RRC configuration.

[0322] In some embodiments, the second information may be, for example, any one of the following: MAC CE; PDCP control PDU; RLC control PDU; SRAP control PDU.

[0323] In some embodiments, the first data may be any one of the following: a signaling radio bearer (SRB); a data radio bearer (DRB); an RLC bearer; an RLC channel; or a logical channel.

[0324] In some embodiments, all or part of the relay terminal devices on the first link can adopt the first feedback mode for data transmission, that is, when receiving an ACK from the next-hop device in the data transmission direction, an ACK is sent to the previous-hop device in the data transmission direction. In this way, the reliability and continuity of data transmission on the first link (service continuity) can be improved.

[0325] To facilitate understanding of the embodiments of the present application, the following describes a possible implementation of the method shown in Figure 6 with reference to examples. This solution is applicable to U2N relay scenarios or U2U relay scenarios.

[0326] In the current feedback mechanism, when a relay terminal device receives data from the previous hop (previous hop) device in the data transmission direction, it directly feedbacks whether the reception is successful. For example, in the scenario shown in Figure 3, after receiving data from the remote terminal device, the relay terminal device #1 can feedback ACK to the remote terminal device. In this way, if the remote terminal receives ACK, it can know that the relay terminal device #1 has successfully received the data, but it cannot know whether the target device has successfully received the data. To this end, the embodiment of the present application provides an enhanced feedback method (that is, the first feedback mode in the aforementioned embodiment), in which the relay terminal device can send ACK feedback information to the previous hop device after receiving ACK feedback from the next hop (next hop) device.

[0327] FIG7 shows a flow chart of an example of a feedback method provided in an embodiment of the present application. In FIG7 , the first device may be a remote terminal device (such as the first remote terminal device), and the second device may be a network device or another remote terminal device (such as the second remote terminal device); alternatively, the second device may be a remote terminal device (such as the first remote terminal device), and the first device may be a network device or another remote terminal device (such as the second remote terminal device).

[0328] As shown in Figure 7, assuming that the data transmission direction is from the first device to the second device, when relay terminal device #1 receives data (such as RLC PDU) from the first device, it will not directly feedback ACK to the first device, but will first forward the data to the next-hop device (relay terminal device #2). After relay terminal device #2 feedbacks ACK to relay terminal device #1, relay terminal device #1 will then feedback ACK to the first device. If relay terminal device #1 receives a NACK from relay terminal device #2, relay terminal device #1 can retransmit the data to relay terminal device #2. After the retransmission is successful and ACK feedback is received from relay terminal device #2, relay terminal device #1 can feedback ACK to the first device. Similarly, when relay terminal device #2 receives data from relay terminal device #1, it will not directly feedback ACK to relay terminal device #1, but will first forward the data to the next-hop device (second device). After the second device feedback ACK to relay terminal device #2, relay terminal device #2 will then feedback ACK to relay terminal device #1. If relay terminal device #2 receives a NACK from the second device, it can retransmit the data to the second device. After the retransmission is successful and an ACK is received from the second device, relay terminal device #2 can send an ACK back to relay terminal device #1. In this way, if the first device receives an ACK from relay terminal device #1, it indicates that the second device has successfully received the data from the first device.

[0329] The above technical solution increases data transmission reliability, but also increases data transmission latency to a certain extent. To reduce data transmission latency, it is possible to configure / dynamically indicate whether each data item should be transmitted using this enhanced feedback method. For data that does not require this enhanced feedback method, the standard method can be used for transmission, thereby reducing overall data transmission latency.

[0330] In some embodiments, the above data may be, for example, any of the following types of data: SRB; DRB; RLC bearer, RLC channel; logical channel.

[0331] In some implementations, the enhanced feedback method can be configured for data through RRC configuration. If the enhanced feedback method is configured for a certain data through RRC configuration, it means that the enhanced feedback method is allowed to be used to transmit the data. The RRC configuration can be associated with specific data (such as SRB / DRB / RLC bearer / RLC channel / logical channel).

[0332] Furthermore, the enhanced feedback mode can be activated via control signaling. For example, after the RRC has configured the enhanced feedback mode, the control signaling can indicate the data to be activated. When certain data is activated, or in other words, when the enhanced feedback mode for that data is activated, the data can be transmitted using the enhanced feedback mode.

[0333] In some embodiments, the control signaling may be, for example, any of the following: MAC CE; PDCP control PDU; RLC control PDU; SRAP control PDU. If the control signaling is a MAC CE, RLC control PDU, or SRAP control PDU, the control signaling must be processed / forwarded by an intermediate node, i.e., the control signaling must be transmitted using a hop-to-hop forwarding method.

[0334] In some embodiments, in a U2N relay scenario, the RRC configuration may, for example, come from a network device in the scenario, and the control signaling may, for example, come from a network device or a remote terminal device in the scenario; in a U2U relay scenario, the RRC configuration may, for example, come from a network device, and the control signaling may, for example, come from one of the remote terminal devices in the scenario (such as a remote terminal device that sends data).

[0335] According to the above technical solution, the relay terminal device can use the enhanced feedback method to transmit specific data that is configured and activated with the enhanced feedback method, and other data can be transmitted in a general manner, thereby reducing the data transmission delay.

[0336] In some embodiments, the network device may adjust the RLC layer configuration (such as the maximum number of retransmissions, etc.) to control the end-to-end delay.

[0337] The communication method provided in the embodiment of the present application enhances data transmission continuity (service continuity) in the relay scenario and avoids the problem of data loss due to the presence of intermediate nodes, especially when there is more than one intermediate node.

[0338] The preferred embodiments of the present application are described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, the technical solution of the present application can be subjected to a variety of simple modifications, and these simple modifications all fall within the scope of protection of the present application. For example, the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present application will no longer describe the various possible combinations separately. For another example, the various different embodiments of the present application can also be arbitrarily combined, as long as they do not violate the idea of ​​the present application, they should also be regarded as the contents disclosed in the present application. For another example, under the premise of no conflict, the various embodiments and / or the technical features in each embodiment described in the present application can be arbitrarily combined with the prior art, and the technical solution obtained after the combination should also fall within the scope of protection of the present application.

[0339] It should also be understood that in the various method embodiments of the present application, the sequence numbers of the above-mentioned processes do not imply a precedence in 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. In addition, in the embodiments of the present application, the terms "downlink," "uplink," and "sidelink" are used to indicate the transmission direction of signals or data, where "downlink" is used to indicate the first direction of transmission of signals or data from a site to a user equipment in a cell, "uplink" is used to indicate the second direction of transmission of signals or data from a user equipment in a cell to a site, and "sidelink" is used to indicate the third direction of transmission of signals or data from user equipment 1 to user equipment 2. For example, "downlink signal" indicates that the transmission direction of the signal is the first direction. In addition, in the embodiments of the present application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships can exist. Specifically, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0340] Based on the aforementioned embodiments, the embodiments of the present application provide corresponding communication devices.

[0341] FIG8 is a schematic diagram of the first structural composition of a communication device provided in an embodiment of the present application, which is applied to a first device. One or more relay terminal devices exist on a first link between the communication device 800 and the second device. As shown in FIG8 , the communication device 800 (hereinafter referred to as the device 800) includes:

[0342] The processing unit 801 is configured to disconnect the first link when a timer times out; wherein the start condition of the timer is related to a state change or an imminent state change of the first link.

[0343] In some embodiments, the apparatus 800 is a remote terminal device, the second device is a network device, and the start conditions of the timer include one or more of the following: receiving a first indication message from the network device, the first indication message being used to instruct the remote terminal device to switch from the first link to other links; successfully accessing other links; receiving a second indication message from the first relay terminal device on the first link, the second indication message being used to indicate a change in the link status between the first relay terminal device and an adjacent device on the first link.

[0344] In some embodiments, a link state change occurs between the first relay terminal device and an adjacent device on the first link, including any of the following: a wireless link failure occurs in the link between the first relay terminal device and the adjacent device; the link quality between the first relay terminal device and the adjacent device is lower than a first threshold; a link switch occurs in the first relay terminal device; a cell switch occurs in the first relay terminal device.

[0345] In some embodiments, the apparatus 800 and the second device are both remote terminal devices, and the start condition of the timer includes: determining to reselect the relay terminal device between the apparatus 800 and the second device.

[0346] In some embodiments, the apparatus 800 is a first network device, the second device is a remote terminal device, and the start condition of the timer includes one or more of the following: sending a third indication message to the remote terminal device, the third indication message is used to instruct the remote terminal device to switch from the first link to other links; receiving a fourth indication message from the remote terminal device, the fourth indication message is used to indicate that the remote terminal device has successfully accessed other links; receiving a fifth indication message from the second network device, the fifth indication message is used to indicate that the remote terminal device has successfully accessed the second network device; sending a sixth indication message to at least one relay terminal device on the first link, the sixth indication message sent to the relay terminal device is used to instruct the relay terminal device to switch links.

[0347] In some embodiments, the apparatus 800 further includes: a restarting unit configured to restart the timer when the apparatus 800 receives data from the first link.

[0348] In some embodiments, the apparatus 800 further includes: a communication unit configured to stop sending data to the second device during the running of the timer.

[0349] In some embodiments, the timing duration of the timer is related to one or more of the following information: the packet delay budget PDB of the data transmitted on the first link; the priority of the data transmitted on the first link; the link quality of the first link; the number of relay terminal devices on the first link; the congestion level of the resource pool; and the resource allocation method.

[0350] In some embodiments, data transmitted on the first link includes multiple quality of service (QoS) flows, the PDB is: the maximum value among the PDBs of the multiple QoS flows; and the priority is: the highest priority among the priorities of the multiple QoS flows.

[0351] In some embodiments, the timing duration of the timer is configured by the network device; or, is determined by the apparatus 800 .

[0352] FIG9 is a second schematic diagram of the structure of a communication device provided in an embodiment of the present application, which is applied to a third device. The first link on which the communication device 900 is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device. As shown in FIG9 , the communication device 900 (hereinafter referred to as the device 900) includes:

[0353] The first communication unit 901 is configured to send first information to the fourth device on the first link, where the first information is used to determine whether there is any uncompleted transmission data on the first link.

[0354] In some embodiments, the apparatus 900 is a first relay terminal device on a first link, and the first information includes: seventh indication information, the seventh indication information is used to indicate the amount of data to be sent by the first relay terminal device; and / or, eighth indication information, the eighth indication information is used to indicate whether the first relay terminal device has cached data to be sent.

[0355] In some embodiments, the seventh indication information includes: the amount of data to be sent by the first relay terminal device, and the identifier of the remote terminal device; the identifier of the remote terminal device is used to indicate that the data to be sent is associated with the remote terminal device.

[0356] In some embodiments, the seventh indication information also includes: an index of a logical channel or an index of a logical channel group; the index of a logical channel is used to indicate that the data to be sent is associated with the logical channel; the index of a logical channel group is used to indicate that the data to be sent is associated with the logical channel group.

[0357] In some embodiments, the eighth indication information includes: a first parameter; and / or, an identifier of a remote terminal device; wherein the first parameter is used to indicate whether the first relay terminal device caches data to be sent; when the eighth indication information includes the first parameter, and the first parameter indicates that the first relay terminal device caches data to be sent, the identifier of the remote terminal device is used to indicate that the data to be sent is associated with the remote terminal device; when the eighth indication information does not include the first parameter, the identifier of the remote terminal device is used to indicate that the first relay terminal device caches data to be sent, and the data to be sent is associated with the remote terminal device.

[0358] In some embodiments, the eighth indication information includes an identifier of the remote terminal device, and also includes: an index of a logical channel or an index of a logical channel group; when the first relay terminal device caches data to be sent, the index of the logical channel is used to indicate that the data to be sent is associated with the logical channel; the index of the logical channel group is used to indicate that the data to be sent is associated with the logical channel group.

[0359] In some embodiments, the fourth device is: a remote terminal device; or a target device; or a relay terminal device adjacent to the first relay terminal device on the first link.

[0360] In some embodiments, the apparatus 900 is a remote terminal device, the fourth device is a target device, and the first information includes: ninth indication information, the ninth indication information is used to indicate: data that the remote terminal device has sent to the target device, and / or data that the remote terminal device has received from the target device.

[0361] In some embodiments, when the ninth indication information is used to indicate data that the remote terminal device has sent to the target device, the ninth indication information includes: an index of the data that the remote terminal device has sent to the target device; when the ninth indication information is used to indicate data that the remote terminal device has received from the target device, the ninth indication information includes: an index of the data that the remote terminal device has received from the target device.

[0362] In some embodiments, apparatus 900 is a target device, the fourth device is a remote terminal device, and the first information includes: tenth indication information, the tenth indication information is used to indicate: data that the target device has sent to the remote terminal device, and / or data that the target device has received from the remote terminal device.

[0363] In some embodiments, when the tenth indication information is used to indicate data that the target device has sent to the remote terminal device, the tenth indication information includes: the index of the data that the target device has sent to the remote terminal device; when the tenth indication information is used to indicate data that the target device has received from the remote terminal device, the tenth indication information includes: the index of the data that the target device has received from the remote terminal device.

[0364] In some embodiments, the first information is sent by the apparatus 900 to the fourth device upon receiving the request information.

[0365] In some embodiments, the first information is sent by the apparatus 900 to the fourth device upon receiving the request information; the request information includes: an identifier of the remote terminal device; the request information also includes: an index of a logical channel or an index of a logical channel group.

[0366] In some embodiments, when the apparatus 900 is a remote terminal device, the request information comes from the target device; when the apparatus 900 is a first relay terminal device on the first link, the request information comes from the remote terminal device or the target device; when the apparatus 900 is a target device, the request information comes from the remote terminal device.

[0367] In some embodiments, the period for the apparatus 900 to send the first information to the fourth device is a first time interval.

[0368] In some embodiments, the first time interval is configured by the network device; or, the first time interval is preconfigured; or, the first time interval is configured by any relay terminal device on the first link; or, the first time interval is configured by a remote terminal device.

[0369] In some embodiments, the first time interval is related to one or more of the following information: the number of relay terminal devices on the first link; the priority of data transmitted on the first link; the congestion level of the resource pool; and quality of service (QoS) parameters.

[0370] In some embodiments, the apparatus 900 is a remote terminal device, and the first information is sent by the remote terminal device to the fourth device when a first condition is met; the first condition includes one or more of the following: receiving a first switching command from a network device, the first switching command being used to instruct the remote terminal device to switch from the first link to other links; the link quality between the remote terminal device and the second relay terminal device is lower than a first threshold, the second relay terminal device being a relay terminal device directly connected to the remote terminal device on the first link; receiving an eleventh indication information from the first relay terminal device on the first link, the eleventh indication information being used to indicate that a link status change has occurred between the first relay terminal device and an adjacent device on the first link.

[0371] In some embodiments, the apparatus 900 is a first relay terminal device on a first link, and the first information is sent by the first relay terminal device to the fourth device when a second condition is met; the second condition includes: a state change occurs in the link between the first relay terminal device and an adjacent device on the first link; and / or, a twelfth indication information is received from the target device, and the twelfth indication information is used to indicate the release of the connection between the first relay terminal device and the target device.

[0372] In some embodiments, a link state change occurs between the first relay terminal device and an adjacent device on the first link, including any of the following: a wireless link failure occurs in the link between the first relay terminal device and the adjacent device; the link quality between the first relay terminal device and the adjacent device is lower than a first threshold; a link switch occurs in the first relay terminal device; a cell switch occurs in the first relay terminal device.

[0373] In some embodiments, the apparatus 900 is a target device, and the target device is a network device, and the first information is sent by the network device to the fourth device when a third condition is met; the third condition includes: sending a first switching command to the remote terminal device; and / or, sending a second switching command to at least one relay terminal device on the first link; wherein the first switching command is used to instruct the remote terminal device to switch from the first link to other links; and the second switching command sent to the relay terminal device is used to instruct the relay terminal device to perform link switching.

[0374] In some embodiments, the first information is carried by one of the following information: radio resource control RRC signaling; packet data convergence protocol PDCP status report; media access control control element MAC CE; radio link control RLC control protocol data unit; sidelink relay adaptation protocol SRAP control protocol data unit.

[0375] In some embodiments, the target device is a network device or a terminal device.

[0376] FIG10 is a third schematic diagram of the structure of a communication device provided in an embodiment of the present application, which is applied to the fourth device. The first link on which the communication device 1000 is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device. As shown in FIG10 , the communication device 1000 (hereinafter referred to as the device 1000) includes:

[0377] The second communication unit 1001 is configured to receive first information from a third device on the first link, where the first information is used to determine whether there is any uncompleted transmission data on the first link.

[0378] In some embodiments, the third device is a first relay terminal device on the first link, and the first information includes: seventh indication information, the seventh indication information is used to indicate the amount of data to be sent by the first relay terminal device; and / or, eighth indication information, the eighth indication information is used to indicate whether the first relay terminal device caches data to be sent.

[0379] In some embodiments, the seventh indication information includes: the amount of data to be sent by the first relay terminal device, and the identifier of the remote terminal device; the identifier of the remote terminal device is used to indicate that the data to be sent is associated with the remote terminal device.

[0380] In some embodiments, the seventh indication information also includes: an index of a logical channel or an index of a logical channel group; the index of a logical channel is used to indicate that the data to be sent is associated with the logical channel; the index of a logical channel group is used to indicate that the data to be sent is associated with the logical channel group.

[0381] In some embodiments, the eighth indication information includes: a first parameter; and / or, an identifier of a remote terminal device; wherein the first parameter is used to indicate whether the first relay terminal device caches data to be sent; when the eighth indication information includes the first parameter, and the first parameter indicates that the first relay terminal device caches data to be sent, the identifier of the remote terminal device is used to indicate that the data to be sent is associated with the remote terminal device; when the eighth indication information does not include the first parameter, the identifier of the remote terminal device is used to indicate that the first relay terminal device caches data to be sent, and the data to be sent is associated with the remote terminal device.

[0382] In some embodiments, the eighth indication information includes an identifier of the remote terminal device, and also includes: an index of a logical channel or an index of a logical channel group; when the first relay terminal device caches data to be sent, the index of the logical channel is used to indicate that the data to be sent is associated with the logical channel; the index of the logical channel group is used to indicate that the data to be sent is associated with the logical channel group.

[0383] In some embodiments, the apparatus 1000 is: a remote terminal device; or a target device; or a relay terminal device adjacent to the first relay terminal device on the first link.

[0384] In some embodiments, the third device is a remote terminal device, the apparatus 1000 is a target device, and the first information includes: ninth indication information, the ninth indication information is used to indicate: data that the remote terminal device has sent to the target device, and / or data that the remote terminal device has received from the target device.

[0385] In some embodiments, when the ninth indication information is used to indicate data that the remote terminal device has sent to the target device, the ninth indication information includes: an index of the data that the remote terminal device has sent to the target device; when the ninth indication information is used to indicate data that the remote terminal device has received from the target device, the ninth indication information includes: an index of the data that the remote terminal device has received from the target device.

[0386] In some embodiments, the third device is a target device, the apparatus 1000 is a remote terminal device, and the first information includes: a tenth indication information, the tenth indication information is used to indicate: data that the target device has sent to the remote terminal device, and / or data that the target device has received from the remote terminal device.

[0387] In some embodiments, when the tenth indication information is used to indicate data that the target device has sent to the remote terminal device, the tenth indication information includes: the index of the data that the target device has sent to the remote terminal device; when the tenth indication information is used to indicate data that the target device has received from the remote terminal device, the tenth indication information includes: the index of the data that the target device has received from the remote terminal device.

[0388] In some embodiments, the second communication unit 1001 is further configured to send request information to the third device before receiving the first information from the third device on the first link, where the request information is used to request the first information.

[0389] In some embodiments, the second communication unit 1001 is further configured to send a request message to the third device before receiving the first information from the third device on the first link, where the request message is used to request the first information; the request message includes: an identifier of the remote terminal device; the request message also includes: an index of the logical channel or an index of the logical channel group.

[0390] In some embodiments, when the apparatus 1000 is a remote terminal device, the third device is a target device or a first relay terminal device on the first link; when the apparatus 1000 is a target device, the third device is a remote terminal device or a first relay terminal device on the first link.

[0391] In some embodiments, when the apparatus 1000 is a remote terminal device, the request information is sent by the remote terminal device to the third device when a fourth condition is met; the fourth condition includes one or more of the following: receiving a first switching command from a network device, the first switching command being used to instruct the remote terminal device to switch from a first link to other links; the link quality between the remote terminal device and the second relay terminal device being lower than a first threshold, the second relay terminal device being a relay terminal device directly connected to the remote terminal device on the first link; receiving a thirteenth indication information from a third relay terminal device on the first link, the thirteenth indication information being used to indicate that a link status change has occurred between the third relay terminal device and an adjacent device on the first link.

[0392] In some embodiments, a link state change occurs between the third relay terminal device and the adjacent device on the first link, including any of the following: a wireless link failure occurs in the link between the third relay terminal device and the adjacent device; the link quality between the third relay terminal device and the adjacent device is lower than a first threshold; a link switch occurs in the third relay terminal device; a cell switch occurs in the third relay terminal device.

[0393] In some embodiments, when the apparatus 1000 is a target device and the target device is a network device, the request information is sent by the network device to the third device when the fifth condition is met; the fifth condition includes: sending a first switching command to the remote terminal device, the first switching command is used to instruct the remote terminal device to switch from the first link to other links; and / or, sending a second switching command to at least one relay terminal device on the first link, the second switching command sent to the relay terminal device is used to instruct the relay terminal device to perform link switching.

[0394] In some embodiments, the first information is carried by one of the following information: radio resource control RRC signaling; packet data convergence protocol PDCP status report; media access control control element MAC CE; radio link control RLC control protocol data unit; sidelink relay adaptation protocol SRAP control protocol data unit.

[0395] In some embodiments, the target device is a network device or a terminal device.

[0396] FIG11 is a fourth schematic diagram of the structure of a communication device provided in an embodiment of the present application, which is applied to a fourth relay terminal device. The communication device 1100 is located on a first link between a first remote terminal device and a target device, and one or more relay terminal devices are present on the first link. As shown in FIG11 , the communication device 1100 (hereinafter referred to as the device 1100 ) includes:

[0397] The third communication unit 1101 is configured to send a second ACK to the sixth device on the first link upon receiving a first positive acknowledgement ACK from the fifth device on the first link; wherein the fifth device is the next-hop device of the apparatus 1100 in the data transmission direction, and the sixth device is the previous-hop device of the apparatus 1100 in the data transmission direction; the first ACK is used to indicate that the fifth device has successfully received the first data from the apparatus 1100; and the second ACK is used to indicate that the apparatus 1100 has successfully received the first data from the sixth device.

[0398] In some embodiments, the third communication unit 1101 is further configured to receive the first data from the sixth device and send the first data to the fifth device before sending the second ACK to the sixth device on the first link.

[0399] In some embodiments, the third communication unit 1101 is further configured to retransmit the first data to the fifth device upon receiving a negative acknowledgment NACK from the fifth device; NACK is used to indicate that the fifth device has not successfully received the first data from the apparatus 1100 .

[0400] In some embodiments, the maximum number of retransmissions for retransmitting the first data to the fifth device is less than or equal to the first value, and the maximum number of retransmissions is configured by the network device.

[0401] In some embodiments, the third communication unit 1101 is specifically configured to: if a first condition is met, send a second ACK to the sixth device upon receiving a first ACK from the fifth device; the first condition includes: allowing the first data to be transmitted using the first feedback mode, and the first feedback mode for the first data is activated.

[0402] In some embodiments, when the target device is a network device, whether the first feedback mode is allowed to be used to transmit the first data is determined based on first information from the network device; whether the first feedback mode for the first data is activated is determined based on second information from the network device or the first remote terminal device; when the target device is a second remote terminal device, whether the first feedback mode is allowed to be used to transmit the first data is determined based on the first information from the network device; whether the first feedback mode for the first data is activated is determined based on second information from the first remote terminal device or the second remote terminal device.

[0403] In some embodiments, the first information is the radio resource control RRC configuration; the second information is any one of the following: media access control control element MAC CE; packet data convergence protocol PDCP control protocol data unit; radio link control RLC control protocol data unit; sidelink relay adaptation protocol SRAP control protocol data unit.

[0404] In some embodiments, the first data is any one of the following: a signaling radio bearer; a data radio bearer; an RLC bearer; an RLC channel; or a logical channel.

[0405] Those skilled in the art should understand that the relevant description of the above-mentioned communication device in the embodiment of the present application can be understood with reference to the relevant description of the communication method in the embodiment of the present application.

[0406] Figure 12 is a schematic structural diagram of a communication device 1200 provided in an embodiment of the present application. The communication device 1200 shown in Figure 12 includes a processor 1210, which can call and run a computer program from a memory to implement the method in the embodiment of the present application.

[0407] Optionally, as shown in FIG12 , the communication device 1200 may further include a memory 1220. The processor 1210 may call and execute a computer program from the memory 1220 to implement the method in the embodiment of the present application.

[0408] The memory 1220 may be a separate device independent of the processor 1210 , or may be integrated into the processor 1210 .

[0409] Optionally, as shown in FIG12 , the communication device 1200 may further include a transceiver 1230 , and the processor 1210 may control the transceiver 1230 to communicate with other devices, specifically, to send information or data to other devices, or to receive information or data sent by other devices.

[0410] The transceiver 1230 may include a transmitter and a receiver. The transceiver 1230 may further include an antenna, and the number of antennas may be one or more.

[0411] Optionally, the communication device 1200 may specifically be the first device of an embodiment of the present application, and the communication device 1200 may implement the corresponding processes implemented by the first device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0412] Optionally, the communication device 1200 may specifically be the third device of the embodiment of the present application, and the communication device 1200 may implement the corresponding processes implemented by the third device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0413] Optionally, the communication device 1200 may specifically be the fourth device of the embodiment of the present application, and the communication device 1200 may implement the corresponding processes implemented by the fourth device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0414] Optionally, the communication device 1200 may specifically be the fourth relay terminal device of the embodiment of the present application, and the communication device 1200 may implement the corresponding processes implemented by the fourth relay terminal device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0415] Figure 13 is a schematic structural diagram of a chip according to an embodiment of the present application. The chip 1300 shown in Figure 13 includes a processor 1310, which can call and run a computer program from a memory to implement the method according to the embodiment of the present application.

[0416] Optionally, as shown in FIG13 , the chip 1300 may further include a memory 1320 , wherein the processor 1310 may call and execute a computer program from the memory 1320 to implement the method in the embodiment of the present application.

[0417] The memory 1320 may be a separate device independent of the processor 1310 , or may be integrated into the processor 1310 .

[0418] Optionally, the chip 1300 may further include an input interface 1330. The processor 1310 may control the input interface 1330 to communicate with other devices or chips, and specifically, may obtain information or data sent by other devices or chips.

[0419] Optionally, the chip 1300 may further include an output interface 1340. The processor 1310 may control the output interface 1340 to communicate with other devices or chips, and specifically, may output information or data to other devices or chips.

[0420] Optionally, the chip can be applied to the first device in the embodiment of the present application, and the chip can implement the corresponding processes implemented by the first device in each method of the embodiment of the present application. For the sake of brevity, it will not be repeated here.

[0421] Optionally, the chip can be applied to the third device in the embodiment of the present application, and the chip can implement the corresponding processes implemented by the third device in each method of the embodiment of the present application. For the sake of brevity, it will not be repeated here.

[0422] Optionally, the chip can be applied to the fourth device in the embodiment of the present application, and the chip can implement the corresponding processes implemented by the fourth device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0423] Optionally, the chip can be applied to the fourth relay terminal device in the embodiment of the present application, and the chip can implement the corresponding processes implemented by the fourth relay terminal device in each method of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0424] 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.

[0425] It should be understood that the processor of the embodiments of the present application may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiment can be completed by hardware integrated logic circuits in the processor or software instructions. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0426] It is understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable 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), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as 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 bus random access memory (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0427] 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.

[0428] An embodiment of the present application also provides a computer-readable storage medium for storing a computer program.

[0429] Optionally, the computer-readable storage medium can be applied to the first device in the embodiment of the present application, and the computer program enables the computer to execute the corresponding processes implemented by the first device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0430] Optionally, the computer-readable storage medium can be applied to the third device in the embodiment of the present application, and the computer program enables the computer to execute the corresponding processes implemented by the third device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0431] Optionally, the computer-readable storage medium can be applied to the fourth device in the embodiment of the present application, and the computer program enables the computer to execute the corresponding processes implemented by the fourth device in the various methods of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0432] Optionally, the computer-readable storage medium can be applied to the fourth relay terminal device in the embodiment of the present application, and the computer program enables the computer to execute the corresponding processes implemented by the fourth relay terminal device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0433] An embodiment of the present application also provides a computer program product, including computer program instructions.

[0434] Optionally, the computer program product can be applied to the first device in the embodiment of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by the first device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0435] Optionally, the computer program product can be applied to the third device in the embodiment of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by the third device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0436] Optionally, the computer program product can be applied to the fourth device in the embodiment of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by the fourth device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0437] Optionally, the computer program product can be applied to the fourth relay terminal device in the embodiment of the present application, and the computer program instructions enable the computer to execute the corresponding processes implemented by the fourth relay terminal device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0438] The embodiment of the present application also provides a computer program.

[0439] Optionally, the computer program can be applied to the first device in the embodiment of the present application. When the computer program runs on a computer, the computer executes the corresponding processes implemented by the first device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0440] Optionally, the computer program can be applied to the third device in the embodiment of the present application. When the computer program runs on the computer, the computer executes the corresponding processes implemented by the third device in the various methods of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0441] Optionally, the computer program can be applied to the fourth device in the embodiment of the present application. When the computer program runs on the computer, the computer executes the corresponding processes implemented by the fourth device in the various methods of the embodiment of the present application. For the sake of brevity, they are not repeated here.

[0442] Optionally, the computer program can be applied to the fourth relay terminal device in the embodiment of the present application. When the computer program runs on the computer, the computer executes the corresponding processes implemented by the fourth relay terminal device in the various methods of the embodiment of the present application. For the sake of brevity, they will not be repeated here.

[0443] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0444] 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.

[0445] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0446] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0447] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0448] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0449] 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 changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method is applied to a first device. There are one or more relay terminal devices on a first link between the first device and a second device. The method includes: Disconnecting the first link when a timer times out; wherein, the start condition of the timer is related to a state change or an impending state change of the first link.

2. The method according to claim 1, wherein, The first device is a remote terminal device, and the second device is a network device. The start condition of the timer includes one or more of the following: Receiving first indication information from the network device, where the first indication information is used to indicate that the remote terminal device switches from the first link to another link; Successfully accessing another link; Receiving second indication information from a first relay terminal device on the first link, where the second indication information is used to indicate that a link between the first relay terminal device and an adjacent device on the first link has a state change.

3. The method according to claim 2, wherein The state change of the link between the first relay terminal device and an adjacent device on the first link includes any one of the following: A radio link failure occurs in the link between the first relay terminal device and the adjacent device; The link quality between the first relay terminal device and the adjacent device is lower than a first threshold; The first relay terminal device performs a link switch; The first relay terminal device performs a cell switch.

4. The method according to claim 1, wherein Both the first device and the second device are remote terminal devices. The start condition of the timer includes: Determining to reselect a relay terminal device between the first device and the second device.

5. The method according to claim 1, wherein The first device is a first network device, and the second device is a remote terminal device. The start condition of the timer includes one or more of the following: Sending third indication information to the remote terminal device, where the third indication information is used to indicate that the remote terminal device switches from the first link to another link; Receiving fourth indication information from the remote terminal device, where the fourth indication information is used to indicate that the remote terminal device has successfully accessed another link; Receiving fifth indication information from a second network device, where the fifth indication information is used to indicate that the remote terminal device has successfully accessed the second network device; Sending sixth indication information to at least one relay terminal device on the first link, and the sixth indication information sent to the relay terminal device is used to indicate that the relay terminal device performs a link switch.

6. The method according to any one of claims 1 to 5, wherein, The method further includes: Restarting the timer when the first device receives data from the first link.

7. The method according to any one of claims 1 to 6, wherein The method further includes: During the running of the timer, stopping sending data to the second device.

8. The method according to any one of claims 1 to 7, wherein The timing duration of the timer is related to one or more of the following information: The packet delay budget PDB of the data transmitted on the first link; The priority of the data transmitted on the first link; The link quality of the first link; The number of relay terminal devices on the first link; The congestion degree of the resource pool; The resource allocation method.

9. According to the method of claim 8, wherein, The data transmitted on the first link includes multiple quality of service QoS flows, The PDB is: the maximum value among the PDBs of the multiple QoS flows; The priority is: the highest priority among the priorities of the multiple QoS flows.

10. The method according to any one of claims 1 to 9, wherein The timing duration of the timer is configured by the network device; or determined by the first device.

11. A communication method, applied to a third device. The first link where the third device is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device. The method includes: Sending first information to a fourth device on the first link, where the first information is used to determine whether there is data with incomplete transmission on the first link.

12. The method according to claim 11, wherein, The third device is the first relay terminal device on the first link, and the first information includes: Seventh indication information, where the seventh indication information is used to indicate the data volume of the data to be sent by the first relay terminal device; and / or, eighth indication information, where the eighth indication information is used to indicate whether the first relay terminal device caches data to be sent.

13. The method according to claim 12, wherein The seventh indication information includes: the data volume of the data to be sent by the first relay terminal device, and the identifier of the remote terminal device; the identifier of the remote terminal device is used to indicate that the data to be sent is associated with the remote terminal device.

14. The method according to claim 13, wherein The seventh indication information further includes: the index of the logical channel or the index of the logical channel group; The index of the logical channel is used to indicate: the data to be sent is associated with the logical channel; The index of the logical channel group is used to indicate: the data to be sent is associated with the logical channel group.

15. The method according to any one of claims 12 to 14, wherein The eighth indication information includes: a first parameter; and / or, the identifier of the remote terminal device; Wherein, the first parameter is used to indicate whether the first relay terminal device caches data to be sent; When the eighth indication information includes the first parameter and the first parameter indicates that the first relay terminal device caches data to be sent, the identifier of the remote terminal device is used to indicate: the data to be sent is associated with the remote terminal device; When the eighth indication information does not include the first parameter, the identifier of the remote terminal device is used to indicate: the first relay terminal device caches data to be sent, and the data to be sent is associated with the remote terminal device.

16. The method according to claim 15, wherein The eighth indication information includes the identifier of the remote terminal device, and further includes: the index of the logical channel or the index of the logical channel group; When the first relay terminal device caches data to be sent, the index of the logical channel is used to indicate: the data to be sent is associated with the logical channel; the index of the logical channel group is used to indicate: the data to be sent is associated with the logical channel group.

17. The method according to any one of claims 12 to 16, wherein, The fourth device is: The remote terminal device; or, The target device; or, The relay terminal device adjacent to the first relay terminal device on the first link.

18. The method according to claim 11, wherein The third device is the remote terminal device, the fourth device is the target device, and the first information includes: The ninth indication information, which is used to indicate: the data that the remote terminal device has sent to the target device, and / or, the data that the remote terminal device has received from the target device.

19. According to the method described in claim 18, wherein, When the ninth indication information is used to indicate the data that the remote terminal device has sent to the target device, the ninth indication information includes: the index of the data that the remote terminal device has sent to the target device; When the ninth indication information is used to indicate the data that the remote terminal device has received from the target device, the ninth indication information includes: the index of the data that the remote terminal device has received from the target device.

20. The method according to claim 11, wherein The third device is the target device, the fourth device is the remote terminal device, and the first information includes: The tenth indication information, which is used to indicate: the data that the target device has sent to the remote terminal device, and / or, the data that the target device has received from the remote terminal device.

21. According to the method described in claim 20, wherein, When the tenth indication information is used to indicate the data that the target device has sent to the remote terminal device, the tenth indication information includes: the index of the data that the target device has sent to the remote terminal device; When the tenth indication information is used to indicate the data that the target device has received from the remote terminal device, the tenth indication information includes: the index of the data that the target device has received from the remote terminal device.

22. According to the method described in any one of claims 11 to 21, wherein, The first information is sent by the third device to the fourth device when the third device receives the request information.

23. According to the method described in claim 14 or 16, wherein, The first information is sent by the third device to the fourth device when the third device receives the request information; The request information includes: the identifier of the remote terminal device; The request information further includes: the index of the logical channel or the index of the logical channel group.

24. According to the method described in claim 22 or 23, wherein, When the third device is the remote terminal device, the request information comes from the target device; When the third device is the first relay terminal device on the first link, the request information comes from the remote terminal device or the target device; When the third device is the target device, the request information comes from the remote terminal device.

25. According to the method described in any one of claims 11 to 21, wherein, The period for the third device to send the first information to the fourth device is a first time interval.

26. The method according to claim 25, wherein, the first time interval is configured by a network device; or, the first time interval is pre-configured; or, the first time interval is configured by any relay terminal device on the first link; or, the first time interval is configured by the remote terminal device.

27. The method according to claim 25 or 26, wherein, the first time interval is related to one or more of the following information: the number of relay terminal devices on the first link; the priority of the data transmitted on the first link; the congestion degree of the resource pool; the quality of service (QoS) parameter.

28. The method according to claim 11, 18 or 19, wherein, the third device is the remote terminal device, and the first information is sent by the remote terminal device to the fourth device when a first condition is met; the first condition includes one or more of the following: receiving a first handover command from a network device, the first handover command being used to instruct the remote terminal device to hand over from the first link to other links; the link quality between the remote terminal device and a second relay terminal device is lower than a first threshold, and the second relay terminal device is a relay terminal device directly connected to the remote terminal device on the first link; receiving an eleventh indication information from a first relay terminal device on the first link, the eleventh indication information being used to indicate that the link between the first relay terminal device and an adjacent device on the first link has a state change.

29. The method according to any one of claims 11 to 17, wherein, the third device is the first relay terminal device on the first link, and the first information is sent by the first relay terminal device to the fourth device when a second condition is met; the second condition includes: the link between the first relay terminal device and an adjacent device on the first link has a state change; and / or, receiving a twelfth indication information from the target device, the twelfth indication information being used to indicate releasing the connection between the first relay terminal device and the target device.

30. The method according to claim 28 or 29, wherein The link between the first relay terminal device and an adjacent device on the first link having a state change includes any one of the following: a radio link failure occurs in the link between the first relay terminal device and the adjacent device; the link quality between the first relay terminal device and the adjacent device is lower than a first threshold; the first relay terminal device has a link handover; the first relay terminal device has a cell handover.

31. The method according to claim 11, 20 or 21, wherein, the third device is the target device, and the target device is a network device, and the first information is sent by the network device to the fourth device when a third condition is met; the third condition includes: sending a first handover command to the remote terminal device; and / or, sending a second handover command to at least one relay terminal device on the first link; Wherein, the first handover command is used to instruct the remote terminal device to hand over from the first link to other links; the second handover command sent to the relay terminal device is used to instruct the relay terminal device to perform link handover.

32. The method according to any one of claims 11 to 31, wherein, The first information is carried by one of the following: Radio Resource Control (RRC) signaling; Packet Data Convergence Protocol (PDCP) status report; Medium Access Control Control Element (MAC CE); Radio Link Control (RLC) control protocol data unit; Sidelink Relay Adaptation Protocol (SRAP) control protocol data unit.

33. The method according to any one of claims 11 to 32, wherein, The target device is a network device or a terminal device.

34. A communication method, applied to a fourth device, where the first link where the fourth device is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device. The method includes: Receiving first information from a third device on the first link, where the first information is used to determine whether there is data with uncompleted transmission on the first link.

35. The method according to claim 34, wherein, The third device is the first relay terminal device on the first link, and the first information includes: Seventh indication information, where the seventh indication information is used to indicate the data volume of the data to be sent by the first relay terminal device; and / or, eighth indication information, where the eighth indication information is used to indicate whether the first relay terminal device caches data to be sent.

36. The method according to claim 35, wherein, The seventh indication information includes: the data volume of the data to be sent by the first relay terminal device, and the identifier of the remote terminal device; the identifier of the remote terminal device is used to indicate that the data to be sent is associated with the remote terminal device.

37. The method according to claim 36, wherein, The seventh indication information further includes: the index of the logical channel or the index of the logical channel group; The index of the logical channel is used to indicate that the data to be sent is associated with the logical channel; The index of the logical channel group is used to indicate that the data to be sent is associated with the logical channel group.

38. The method according to any one of claims 35 to 37, wherein, The eighth indication information includes: a first parameter; and / or, the identifier of the remote terminal device; Wherein, the first parameter is used to indicate whether the first relay terminal device caches data to be sent; When the eighth indication information includes the first parameter and the first parameter indicates that the first relay terminal device caches data to be sent, the identifier of the remote terminal device is used to indicate that the data to be sent is associated with the remote terminal device; When the eighth indication information does not include the first parameter, the identifier of the remote terminal device is used to indicate that the first relay terminal device caches data to be sent and the data to be sent is associated with the remote terminal device.

39. The method according to claim 38, wherein, The eighth indication information includes the identifier of the remote terminal device, and further includes: an index of a logical channel or an index of a logical channel group; In the case where the first relay terminal device caches data to be transmitted, the index of the logical channel is used to indicate that the data to be transmitted is associated with the logical channel; the index of the logical channel group is used to indicate that the data to be transmitted is associated with the logical channel group.

40. The method according to any one of claims 35 to 39, wherein, The fourth device is: the remote terminal device; or, the target device; or, a relay terminal device adjacent to the first relay terminal device on the first link.

41. The method according to claim 34, wherein, The third device is the remote terminal device, the fourth device is the target device, and the first information includes: ninth indication information, which is used to indicate: data that the remote terminal device has sent to the target device, and / or data that the remote terminal device has received from the target device.

42. The method according to claim 41, wherein, In the case where the ninth indication information is used to indicate data that the remote terminal device has sent to the target device, the ninth indication information includes: an index of the data that the remote terminal device has sent to the target device; In the case where the ninth indication information is used to indicate data that the remote terminal device has received from the target device, the ninth indication information includes: an index of the data that the remote terminal device has received from the target device.

43. The method according to claim 34, wherein, The third device is the target device, the fourth device is the remote terminal device, and the first information includes: tenth indication information, which is used to indicate: data that the target device has sent to the remote terminal device, and / or data that the target device has received from the remote terminal device.

44. The method according to claim 43, wherein, In the case where the tenth indication information is used to indicate data that the target device has sent to the remote terminal device, the tenth indication information includes: an index of the data that the target device has sent to the remote terminal device; In the case where the tenth indication information is used to indicate data that the target device has received from the remote terminal device, the tenth indication information includes: an index of the data that the target device has received from the remote terminal device.

45. The method according to any one of claims 34 to 44, wherein Before receiving the first information from a third device on the first link, the method further includes: sending request information to the third device, where the request information is used to request the first information.

46. The method according to claim 37 or 39, wherein Before receiving the first information from a third device on the first link, the method further includes: sending request information to the third device, where the request information is used to request the first information; The request information includes: the identifier of the remote terminal device; The request information further includes: an index of the logical channel or an index of the logical channel group.

47. The method according to claim 45 or 46, wherein, When the fourth device is the remote terminal device, the third device is the target device or the first relay terminal device on the first link; When the fourth device is the target device, the third device is the remote terminal device or the first relay terminal device on the first link.

48. The method according to any one of claims 45 to 47, wherein When the fourth device is the remote terminal device, the request information is sent by the remote terminal device to the third device when a fourth condition is satisfied; The fourth condition includes one or more of the following: Receiving a first handover command from a network device, the first handover command being used to instruct the remote terminal device to hand over from the first link to another link; The link quality between the remote terminal device and a second relay terminal device is lower than a first threshold, and the second relay terminal device is a relay terminal device directly connected to the remote terminal device on the first link; Receiving thirteenth indication information from a third relay terminal device on the first link, the thirteenth indication information being used to indicate that the link between the third relay terminal device and an adjacent device on the first link has changed state.

49. The method according to claim 48, wherein, The link between the third relay terminal device and an adjacent device on the first link changing state includes any one of the following: A radio link failure occurs in the link between the third relay terminal device and the adjacent device; The link quality between the third relay terminal device and the adjacent device is lower than a first threshold; The third relay terminal device performs a link handover; The third relay terminal device performs a cell handover.

50. The method according to any one of claims 45 to 47, wherein When the fourth device is the target device and the target device is a network device, the request information is sent by the network device to the third device when a fifth condition is satisfied; The fifth condition includes: Sending a first handover command to the remote terminal device, the first handover command being used to instruct the remote terminal device to hand over from the first link to another link; and / or, Sending a second handover command to at least one relay terminal device on the first link, the second handover command sent to the relay terminal device being used to instruct the relay terminal device to perform a link handover.

51. The method according to any one of claims 34 to 50, wherein The first information is carried by one of the following: Radio Resource Control (RRC) signaling; Packet Data Convergence Protocol (PDCP) status report; Medium Access Control Control Element (MAC CE); Radio Link Control (RLC) control protocol data unit; Sidelink Relay Adaptation Protocol (SRAP) control protocol data unit.

52. The method according to any one of claims 34 to 51, wherein The target device is a network device or a terminal device.

53. A communication method, applied to a fourth relay terminal device, the fourth relay terminal device being located on a first link between a first remote terminal device and a target device, and one or more relay terminal devices existing on the first link, the method comprising: In the case of receiving a first positive acknowledgment ACK from a fifth device on the first link, send a second ACK to a sixth device on the first link; wherein, the fifth device is the next-hop device of the fourth relay terminal device in the data transmission direction, and the sixth device is the previous-hop device of the fourth relay terminal device in the data transmission direction; the first ACK is used to indicate that the fifth device has successfully received the first data from the fourth relay terminal device; the second ACK is used to indicate that the fourth relay terminal device has successfully received the first data from the sixth device.

54. The method according to claim 53, wherein, Before sending the second ACK to the sixth device on the first link, the method further includes: Receiving the first data from the sixth device and sending the first data to the fifth device.

55. The method according to claim 53 or 54, wherein, The method further includes: In the case of receiving a negative acknowledgment NACK from the fifth device, retransmit the first data to the fifth device; the NACK is used to indicate that the fifth device has not successfully received the first data from the fourth relay terminal device.

56. The method according to claim 55, wherein, The maximum number of retransmissions of the first data to the fifth device is less than or equal to a first value, and the maximum number of retransmissions is configured by a network device.

57. The method according to any one of claims 53 to 56, wherein, The step of, in the case of receiving a first ACK from a fifth device on the first link, sending a second ACK to a sixth device on the first link, includes: If a first condition is satisfied, then in the case of receiving the first ACK from the fifth device, send a second ACK to the sixth device; The first condition includes: It is allowed to transmit the first data using a first feedback mode, and the first feedback mode for the first data is activated.

58. The method according to claim 57, wherein, In the case where the target device is a network device, whether it is allowed to transmit the first data using the first feedback mode is determined based on first information from the network device; whether the first feedback mode for the first data is activated is determined based on second information from the network device or the first remote terminal device; In the case where the target device is a second remote terminal device, whether it is allowed to transmit the first data using the first feedback mode is determined based on first information from the network device; whether the first feedback mode for the first data is activated is determined based on second information from the first remote terminal device or the second remote terminal device.

59. The method according to claim 58, wherein, The first information is radio resource control RRC configuration; the second information is any one of the following: Media access control control element MAC CE; Packet data convergence protocol PDCP control protocol data unit; Radio link control RLC control protocol data unit; Sidelink relay adaptation protocol SRAP control protocol data unit.

60. The method according to any one of claims 53 to 59, wherein, The first data is any one of the following: Signaling radio bearer; Data radio bearer; RLC bearer; RLC channel; Logical channel.

61. A communication device, where there is one or more relay terminal devices on a first link between the device and a second device, the device comprising: A processing unit, configured to disconnect the first link when a timer times out; wherein, the start condition of the timer is related to a state change or an impending state change of the first link.

62. A communication device, where a first link where the device is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device, the device comprising: A first communication unit, configured to send first information to a fourth device on the first link, the first information being used to determine whether there is data with uncompleted transmission on the first link.

63. A communication device, where a first link where the device is located includes a remote terminal device, a target device, and one or more relay terminal devices between the remote terminal device and the target device, the device comprising: A second communication unit, configured to receive first information from a third device on the first link, the first information being used to determine whether there is data with uncompleted transmission on the first link.

64. A communication device, where the device is located on a first link between a first remote terminal device and a target device, and there is one or more relay terminal devices on the first link, the device comprising: A third communication unit, configured to send a second ACK to a sixth device on the first link when receiving a first positive acknowledgment (ACK) from a fifth device on the first link; wherein, the fifth device is the next-hop device of the device in the data transmission direction, and the sixth device is the previous-hop device of the device in the data transmission direction; the first ACK is used to indicate that the fifth device has successfully received first data from the device; the second ACK is used to indicate that the device has successfully received the first data from the sixth device.

65. A communication device, comprising: A processor and a memory, the memory being used to store a computer program, the processor being used to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 10, or the method according to any one of claims 11 to 33, or the method according to any one of claims 34 to 52, or the method according to any one of claims 53 to 60.

66. A chip, comprising: A processor, used to call and run a computer program from a memory, so that a device installed with the chip executes the method according to any one of claims 1 to 10, or the method according to any one of claims 11 to 33, or the method according to any one of claims 34 to 52, or the method according to any one of claims 53 to 60.

67. A computer-readable storage medium for storing a computer program, the computer program causing a computer to execute the method according to any one of claims 1 to 10, or the method according to any one of claims 11 to 33, or the method according to any one of claims 34 to 52, or the method according to any one of claims 53 to 60.

68. A computer program product comprising computer program instructions that cause a computer to execute the method according to any one of claims 1 to 10, or the method according to any one of claims 11 to 33, or the method according to any one of claims 34 to 52, or the method according to any one of claims 53 to 60.

69. A computer program, the computer program causing a computer to execute the method according to any one of claims 1 to 10, or the method according to any one of claims 11 to 33, or the method according to any one of claims 34 to 52, or the method according to any one of claims 53 to 60.

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