Relay reselection method, system and equipment

Abstract

The invention discloses a relay reselection method, system and device, and belongs to the technical field of communication, and the relay reselection method comprises the following steps: under the condition that relay reselection is triggered by the link condition between a first device and a first relay device, performing relay reselection on the first relay device; the first equipment executes relay reselection or link switching based on any one of the following items: compared with the prior art, the number of the same relay equipment in a relay link is the largest; compared with the relay before reselection, the total hop count change of the relay link is minimum; the total hop count of the relay link is minimum; wherein the first equipment is a far-end terminal or second relay equipment, and the numerical value of the total hop count is equal to the total number of the relay equipment in the relay link, or the numerical value of the total hop count is equal to the sum of the total number of the relay equipment in the relay link and 1. Therefore, the relay reselection can be performed under the condition that the link triggers the relay reselection, so that the subsequent relay communication based on the reselection relay equipment is facilitated, and the communication efficiency and quality are ensured.

Description

Technical Field

[0001] The present application belongs to the field of communication technology, and specifically relates to a relay reselection method, system and device. Background Art

[0002] Relay technology in wireless communication systems refers to adding one or more relay devices between the base station and the terminal to forward the wireless signal once or multiple times, that is, the wireless signal needs to go through one or more hops to reach the terminal. Relay technology can not only be used to expand cell coverage and fill in cell coverage blind spots, but also to increase cell capacity through spatial resource reuse. For indoor coverage, relay technology can also overcome penetration loss and improve indoor coverage quality.

[0003] When a problem occurs in a certain hop link of the relay communication link, the communication quality will be affected, and relay reselection is required to facilitate subsequent relay communication based on the reselected relay. However, in the related art, there is no clear solution for how to perform relay reselection for relay communication in multi-hop scenarios or scenarios where the link includes multiple relays. Summary of the invention

[0004] The embodiments of the present application provide a relay reselection method, system and apparatus, which can reselect a relay device when a link triggers a relay reselection condition, so as to facilitate subsequent relay communication based on the reselected relay device, thereby ensuring the efficiency and quality of communication.

[0005] In a first aspect, a relay reselection method is provided, the method comprising:

[0006] In the case where relay reselection is triggered due to the link condition between the first device and the first relay device, the first device performs relay reselection or link switching based on any one of the following:

[0007] Compared with before relay reselection, the number of identical relay devices in the relay link is the largest;

[0008] Compared with before relay reselection, the total number of hops of the relay link changes minimally;

[0009] The total number of hops in the relay link is minimal;

[0010] The first device is a remote terminal or a second relay device, and the value of the total number of hops is equal to the total number of relay devices in the relay link, or the value of the total number of hops is equal to the total number of relay devices in the relay link plus 1.

[0011] In a second aspect, a relay reselection system is provided, the system comprising: a first device, a first relay device;

[0012] The first device is configured to, when relay reselection is triggered due to a link condition between the first device and the first relay device, perform relay reselection or link switching based on any one of the following:

[0013] Compared with before relay reselection, the number of identical relay devices in the relay link is the largest;

[0014] Compared with before relay reselection, the total number of hops of the relay link changes minimally;

[0015] The total number of hops in the relay link is minimal;

[0016] The first device is a remote terminal or a second relay device, and the value of the total number of hops is equal to the total number of relay devices in the relay link, or the value of the total number of hops is equal to the total number of relay devices in the relay link plus 1.

[0017] In a third aspect, a device is provided, comprising a processor and a memory, wherein the memory stores a program or instruction that can be executed on the processor, and when the program or instruction is executed by the processor, the steps of the relay reselection method as described in the first aspect are implemented.

[0018] In a fourth aspect, a readable storage medium is provided, on which a program or instruction is stored, and when the program or instruction is executed by a processor, the steps of the relay reselection method as described in the first aspect are implemented.

[0019] In an embodiment of the present application, when relay reselection is triggered due to the link situation between the first device and the first relay device, the first device performs relay reselection or link switching based on any one of the following: the number of identical relay devices in the relay link is the largest compared to before relay reselection; the total number of hops in the relay link changes the smallest compared to before relay reselection; the total number of hops in the relay link is the smallest; wherein the first device is a remote terminal or a second relay device, and the value of the total number of hops is equal to the total number of relay devices in the relay link, or the value of the total number of hops is equal to the total number of relay devices in the relay link plus 1. In this way, relay reselection can be performed quickly and accurately when the link triggers the relay reselection condition, so that relay communication can be performed based on the reselected relay device in the future, ensuring the efficiency and quality of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a block diagram of a wireless communication system to which the embodiments of the present application can be applied;

[0021] Figure 2 It is a schematic diagram of a UE-to-Network scenario in an embodiment of the present application;

[0022] Figure 3is a flowchart of the steps of a relay reselection method in an embodiment of the present application;

[0023] Figure 4 It is a schematic diagram of an application scenario in an embodiment of the present application;

[0024] Figure 5 It is another application scenario schematic diagram in the embodiment of the present application;

[0025] Figure 6 This is another application scenario schematic diagram in the embodiment of the present application;

[0026] Figure 7 is a structural diagram of a relay reselection system in an embodiment of the present application;

[0027] Figure 8 is a schematic diagram of the structure of a device in an embodiment of the present application;

[0028] Fig. 9 It is a structural diagram of a network side device in an embodiment of the present application. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of this application.

[0030] The terms "first", "second", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of one type, and the number of objects is not limited, for example, the first object can be one or more. In addition, "or" in this application represents at least one of the connected objects. For example, "A or B" covers three schemes, namely, Scheme 1: including A but not including B; Scheme 2: including B but not including A; Scheme 3: including both A and B. The character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0031] The term "indication" in this application can be a direct indication (or explicit indication) or an indirect indication (or implicit indication). A direct indication can be understood as the sender explicitly informing the receiver of specific information, operations to be performed, or request results in the sent indication; an indirect indication can be understood as the receiver determining the corresponding information according to the indication sent by the sender, or making a judgment and determining the operation to be performed or the request result according to the judgment result.

[0032] It is worth noting that the technology described in the embodiments of the present application is not limited to the Long Term Evolution (LTE) / LTE-Advanced (LTE-A) system, but can also be used in other wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-carrier Frequency-Division Multiple Access (SC-FDMA) or other systems. The terms "system" and "network" in the embodiments of the present application are often used interchangeably, and the described technology can be used for the systems and radio technologies mentioned above as well as for other systems and radio technologies. The following description describes a New Radio (NR) system for illustrative purposes, and NR terminology is used in most of the following descriptions, but these technologies can also be applied to systems other than NR systems, such as the 6th generation (6 th Generation, 6G) communication system.

[0033] Figure 1A block diagram of a wireless communication system applicable to an embodiment of the present application is shown. The wireless communication system includes a terminal 11 and a network side device 12. Among them, the terminal 11 can be a mobile phone, a tablet computer (Tablet Personal Computer), a laptop computer (Laptop Computer), a notebook computer, a personal digital assistant (Personal Digital Assistant, PDA), a handheld computer, a netbook, an ultra-mobile personal computer (Ultra-mobile Personal Computer, UMPC), a mobile Internet device (Mobile Internet Device, MID), an augmented reality (Augmented Reality, AR), a virtual reality (Virtual Reality, VR) device, a robot, a wearable device (Wearable Device), an aircraft (flight vehicle), a vehicle-mounted device (Vehicle User Equipment, VUE), a ship-mounted device, a pedestrian terminal (Pedestrian User Equipment, PUE), a smart home (home appliances with wireless communication functions, such as refrigerators, televisions, washing machines or furniture, etc.), a game console, a personal computer (Personal Computer, PC), a teller machine or a self-service machine and other terminal side devices. Wearable devices include: smart watches, smart bracelets, smart headphones, smart glasses, smart jewelry (smart bracelets, smart bracelets, smart rings, smart necklaces, smart anklets, smart anklets, etc.), smart wristbands, smart clothing, etc. Among them, the vehicle-mounted device can also be called a vehicle-mounted terminal, a vehicle-mounted controller, a vehicle-mounted module, a vehicle-mounted component, a vehicle-mounted chip or a vehicle-mounted unit, etc. It should be noted that the specific type of the terminal 11 is not limited in the embodiment of the present application. The network side device 12 may include an access network device or a core network device, wherein the access network device may also be referred to as a radio access network (Radio Access Network, RAN) device, a radio access network function or a radio access network unit. The access network device may include a base station, a wireless local area network (Wireless Local Area Network, WLAN) access point (Access Point, AS) or a wireless fidelity (Wireless Fidelity, WiFi) node, etc.Among them, the base station may be referred to as a Node B (NB), an evolved Node B (eNB), a next generation Node B (gNB), a New Radio Node B (NR Node B), an access point, a Relay Base Station (RBS), a Serving Base Station (SBS), a Base Transceiver Station (BTS), a radio base station, a radio transceiver, a Basic Service Set (BSS), an Extended Service Set (ESS), a Home Node B (HNB), a Home Evolved Node B (home evolved Node B), a Transmission Reception Point (TRP) or other appropriate terms in the relevant field. As long as the same technical effect is achieved, the base station is not limited to specific technical vocabulary. It should be noted that in the embodiment of the present application, only the base station in the NR system is used as an example for introduction, and the specific type of the base station is not limited.

[0034] To facilitate understanding of the technical solutions provided by the present application, the main technical concepts involved in the embodiments of the present application are briefly described below.

[0035] Relay mechanism:

[0036] Relay technology in wireless communication systems refers to adding one or more relay devices between the base station and the terminal to forward the wireless signal once or multiple times, that is, the wireless signal needs to go through multiple hops to reach the terminal. Relay technology can not only be used to expand cell coverage and fill in cell coverage blind spots, but also to increase cell capacity through spatial resource reuse. For indoor coverage, relay technology can also overcome penetration loss and improve indoor coverage quality.

[0037] Taking two-hop relay as an example, wireless relay divides a "base station"-"terminal" link into two links: "base station"-"relay station" and "relay station"-"terminal", thereby replacing a link with poor quality with two links with better quality to obtain higher link capacity and better coverage.

[0038] The relay technology currently supported in LTE is the UE-to-Network relay scenario, that is, the relay device is connected to the user equipment at one end and the network at the other end. The user equipment (UE) connected to the relay device is called the remote UE. NR also supports the UE-to-Network relay scenario in Release-17, where the relay terminal is the relay UE and the remote terminal is the remote UE.

[0039] In the existing Relay mechanism, Figure 2 As shown in the figure, for the UE-to-Network relay scenario, the remote UE needs to transmit data with the network side, but due to poor coverage, a relay UE is found for the relay, where the relay UE and the base station are connected via a Uu interface, and the relay UE and the remote UE are connected via a sidelink interface (e.g., PC5 interface). Generally speaking, the relay UE is open and can serve any remote UE. The UE-to-UE relay scenario is similar to the UE-to-Network relay scenario, except that the two ends of the relay UE are connected to different UEs. The relevant design of the UE-to-UE relay scenario is still under discussion.

[0040] U2N Relay (UE-to-Network Relay) selection and reselection:

[0041] In NR and its subsequent iterations (such as beyond 5G), when the remote UE meets certain conditions, the relay selection or relay reselection of the U2N relay UE will be performed. The current relay reselection is mainly determined based on the link between the UE and the base station, as well as the signal quality on the sidelink. Simply put, when the signal quality of the remote UE's Uu link is poor, it will trigger the remote UE to select Relay. When selecting, SD-RSRP (Sidelink Discovery Reference Signal Received Power) is used to determine whether the relay UE meets the conditions (that is, whether it supports being a relay device). The current Relay reselection is mainly when the remote UE finds that the measurement result of SD-RSRP or SL-RSRP is less than a certain threshold value, or when the upper layer of the remote UE triggers, etc., it will initiate the Relay UE reselection.

[0042] U2U Relay (UE-to-UE Relay) selection and reselection:

[0043] For single-hop relay communication, there are two modes for relay discovery and selection, model A relay discovery and selection process, and model B relay discovery and selection process. In model A relay discovery and selection, for the U2U relay scenario, the U2U relay UE will broadcast nearby UEs, and then the end UE (or remote UE) will determine which U2U relay UEs can choose to access based on the received discovery announcement message. There are also certain rules for relay reselection in the U2U Relay scenario. For example, when the remote UE finds that the link quality of this hop is not good, reselection can be triggered. Or, when the relay UE finds that the link with the target remote UE has a radio link failure (RLF), it can notify the source remote UE, and the source remote terminal triggers reselection.

[0044] In the related art, especially for relay communications in multi-hop scenarios, there is no clear solution for how to perform relay reselection. Therefore, in order to solve the relay reselection problem, the embodiment of the present application proposes a relay reselection method, which can perform relay reselection when the relay reselection condition is triggered, so that subsequent relay communication can be performed based on the reselected relay device to ensure communication quality.

[0045] The information indication method, apparatus and device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings through some embodiments and their application scenarios.

[0046] First, see Figure 3 , Figure 3 A flowchart of a relay reselection method provided in an embodiment of the present application is shown. Figure 3 As shown, the method comprises the following steps:

[0047] Step S310: When relay reselection is triggered due to the link condition between the first device and the first relay device, the first device performs relay reselection or link switching based on any one of the following:

[0048] Item A-1: ​​Compared with before relay reselection, the number of identical relay devices in the relay link is the largest;

[0049] Item A-2: Compared with before relay reselection, the total number of hops of the relay link changes minimally;

[0050] A-3: The total number of hops in the relay link is minimal;

[0051] The first device is a remote terminal or a second relay device, and the value of the total number of hops is equal to the total number of relay devices in the relay link, or the value of the total number of hops is equal to the total number of relay devices in the relay link plus 1.

[0052] It should be noted that the total hop count can be calculated by referring to any of the following methods:

[0053] (1) Method 1: The total number of hops is equal to the total number of relay devices in the relay link. For example, in the U2U scenario, the source remote UE and the target remote UE are connected via 3 relay devices. If Method 1 is used, the total number of hops in the link (i.e., the number of hops between the source remote UE and the target remote UE) is 3. In the U2N scenario, the remote UE and the base station are connected via 2 relay devices. If Method 1 is used, the total number of hops in the link (i.e., the number of hops between the source remote UE and the base station) is 2.

[0054] (2) Mode 2: The total number of hops is equal to the total number of relay devices in the relay link plus 1. For example, in a U2U scenario, the source remote UE and the target remote UE are connected via three relay devices. If Mode 2 is used, the total number of hops of the link (i.e., the number of hops between the source remote UE and the target remote UE) is 4, where

[0055] The link between the source remote UE and the first relay device is the first hop, and the link between the third relay device and the target remote UE is the fourth hop. In the U2N scenario, the remote UE and the base station are connected through two relay devices. At this time, if method 2 is referred to, the total number of hops of the link (i.e., the number of hops between the source remote UE and the base station) is 3, of which the link between the remote UE and the first relay device is the first hop, and the link between the second relay device and the base station is the third hop.

[0056] In the embodiment of the present application, the first relay device, the second relay device and the remote terminal may be Figure 1 For the terminal 11 in the example, please refer to the above text, and no further description is given here. In the present application, the terminal terminal can also be understood as a user equipment UE.

[0057] Among them, the first relay device and the second relay device are both relay devices that forward signals in the relay communication link. The remote terminal refers to the remote UE or the end UE, and the remote terminal may also be the source remote UE (source remote UE), the end UE (end UE) or the target remote UE (target remote UE). The link condition between the first device and the first relay device triggers the relay reselection, specifically including: when the measurement result of PC5 RSRP is less than or equal to a threshold value, the relay reselection or link switching is triggered, the V2X layer / Prose layer of the first device triggers the relay reselection or link switching, and the V2X layer / Prose layer of the first relay device triggers the relay reselection or link switching. For example, Figure 4 A schematic diagram of an application scenario of an embodiment of the present application is shown, UE1 to UE5 are all relay devices, remote UE A is a remote terminal, remote UE B is the remote terminal of the opposite end, and remote UE B and the base station are collectively referred to as the target remote terminal. If the total number of hops is calculated as equal to the total number of relay devices in the relay link, Figure 4 The total number of hops in the illustrated application scenario is 5, and the total number of hops is calculated as the total number of relay devices in the relay link plus 1. Figure 4 The total number of hops in the illustrated application scenario is 6.

[0058] Specifically, relay reselection refers to reselecting a relay device and establishing a relay link with the reselected relay device. It can be reselecting all relay devices in the relay link, or reselecting some (1 or more) relay devices in the relay link. For example, it can be reselecting the relay device of the current link that triggered the relay reselection. Relay reselection is performed in any of the ways from A-1 to A-3. Link switching refers to switching the link that triggered the relay reselection, and link switching also performs relay reselection in any of the ways from A-1 to A-3. Take relay reselection as an example below:

[0059] For item A-1, compared with before relay reselection, the maximum number of identical relay devices in the relay link means: the relay devices of several hops after the first relay device are regarded as a whole, and only the relay devices of the current hop link that triggers the relay reselection are reselected, for example, another relay device is selected to replace the relay device of this hop, and the other relay devices in the original relay link remain unchanged, so that the number of identical relay devices in the relay link is maximized. Among them, the same relay device refers to the relay device with the same ID, which can be one of the V2X layer ID, application layer ID, prose layer ID, user info, L2 ID, etc. Relay reselection is based on item A-1. Since not all relays are reselected, the reselected relay can be quickly determined, and only the new link related to the newly selected relay device needs to be reestablished, which ensures the rapid establishment of the relay communication link.

[0060] For item A-2, the minimum change in the total number of hops of the relay link compared to before the relay reselection means: the relay devices of several hops behind the first relay device are regarded as a whole, and only the relay devices of the current hop link that triggers the relay reselection are reselected, and the relay device that satisfies the minimum change in the total number of hops is selected to establish a relay link to replace the relay link that triggers the relay reselection. Among them, the minimum change in the total number of hops includes the minimum change in the total number of hops in the decreasing direction, the minimum change in the total number of hops in the increasing direction, and the total number of hops remains unchanged. Relay reselection is performed based on item A-2. Since not all relays are reselected, the reselected relay can be quickly determined, and only the new link related to the newly selected relay device needs to be reestablished, which ensures the rapid establishment of the relay communication link.

[0061] For item A-3, the minimum total number of hops of the relay link means that the first device reselects the target remote terminal as the target remote terminal similar to a single hop, and performs relay reselection in order from small to large in the order of the number of hops from the first device to the target remote terminal, until a relay device that supports being a relay device is selected, thereby reducing the total number of hops of the relay link as a whole. When performing relay reselection based on item A-3, the total number of relay devices that need to be selected is small, so that the relay device can be quickly determined and a relay communication link can be established.

[0062] The specific implementation of the relay reselection method is described in detail below and will not be repeated here. The relay reselection method provided in the embodiment of the present application can perform relay reselection when relay reselection is triggered, so that subsequent relay communication based on the reselected relay device can be performed to ensure the efficiency and quality of communication.

[0063] It should be noted that the same principles as those introduced in the above items A-1 to A-3 may be followed for link switching. For example, in one case, the remote UE or relay device (such as an upstream device in a certain jump link when a link quality problem occurs) may directly switch to another relay link (the other relay link may overlap with part of the link before the switch, or may not overlap with the link before the switch), or directly switch to a direct connection with the device at the other end (such as a target remote UE or base station).

[0064] In a specific implementation, the first device performs relay reselection or link switching based on the largest number of identical relay devices in the relay link compared to before the relay reselection, including:

[0065] The first device uses the next-hop relay device of the first relay device as a target remote device, and performs relay reselection or link switching.

[0066] The next-hop relay device refers to the next-hop device for relay device signal transmission, for example, Figure 4 As shown, when the link condition between the first device UE2 and the first relay device UE3 causes UE2 to trigger relay reselection, the next-hop relay device of the first relay device UE3 is UE4; when the link condition between the first device UE3 and the first relay device UE2 causes UE3 to trigger relay reselection, the next-hop relay device of the first relay device UE2 is UE1.

[0067] In the embodiment of the present application, the several hop relay devices behind the first relay device are regarded as a whole, and only the relay device of the current hop link that triggers the relay reselection is reselected, that is, the next hop relay device of the first relay device is used as the target remote device, and then the relay reselection or link switching is performed on the target remote device, wherein the target remote device refers to the device based on which the relay reselection or link switching is performed to determine the device that supports being a relay device from the relay devices connected to the target remote device. In the specific implementation, the first device determines a relay device that is directly connected to the next hop relay device of the first relay device to replace the first relay device. At this time, compared with before the relay reselection, the number of identical relay devices in the relay link is the largest, that is, only one relay device is different, and, compared with before the relay reselection, the total number of hops remains unchanged, which guarantees the stability and compatibility of the link to the greatest extent.

[0068] For example, Figure 5As shown, when relay reselection is triggered due to the link situation between the first device UE2 and the first relay device UE3, UE4 is the next-hop relay device of the first relay device, UE4 is taken as the target remote device, and relay reselection or link switching is performed. At this time, the first device UE2 will select the relay device UE X directly connected to UE4 as the target relay device, and then UE2 establishes a relay link of UE2-UE X-UE4 to replace the relay link of UE2-UE3-UE4 before the relay reselection is triggered.

[0069] In a specific implementation, there may be multiple relay devices directly connected to the next-hop relay device, and any relay device may be selected from the multiple relay devices directly connected to the next-hop relay device as the target relay device to replace the first relay device. Figure 5 In the example, since the link condition between the first device UE2 and the first relay device UE3 triggers the relay reselection, UE X and UE Z are both relay devices directly connected to the next-hop relay device UE4. In one embodiment, UE X is selected as the target relay device to replace the first relay device UE3 before the relay reselection. In another embodiment, UE Z is selected as the target relay device to replace the first relay device UE3 before the relay reselection.

[0070] In a specific implementation, the first device performs relay reselection or link switching based on the fact that the total number of hops of the relay link changes minimally compared to before the relay reselection, including:

[0071] The first device determines a result of a first PC5 RSRP measured between the first device and a next-hop relay device of the first relay device, and when the result of the first PC5 RSRP is greater than or equal to a first threshold, the first device initiates any one of the following processes to the next-hop relay device of the first relay device:

[0072] Item B-1: PC5 unicast connection establishment process;

[0073] Item B-2: mode-B discovery process;

[0074] Item B-3: Integrated discovery process.

[0075] In the embodiment of the present application, the relay devices following the first relay device are regarded as a whole, and only the relay device of this hop is relayed and reselected to ensure that the total number of hops changes in the direction of reduction to a minimum. When the result of the first PC5 RSRP measured between the next-hop relay devices of the first device is greater than or equal to the first threshold, the first device initiates any one of the processes from B-1 to B-3 to the next-hop relay device of the first relay device to achieve relay reselection or link switching. At this time, the total number of hops is reduced by one hop, and at the same time, the number of identical relay devices in the relay link is the largest compared to before the relay reselection. Among them, PC5 RSRP includes: SD-RSRP and / or SL-RSRP.

[0076] In a specific implementation, the first device exchanges a discovery message or a destination call routing (DCR) message with the next-hop relay device of the first relay device to attempt to establish a PC5 unicast connection. Figure 5 As shown, when the link condition between the first device UE2 and the first relay device UE3 triggers relay reselection, the next-hop relay device of the first relay device UE3 is UE4. At this time, the first device UE2 will try to establish a unicast connection with UE4.

[0077] In a specific implementation, the first device performs relay reselection or link switching based on the fact that the total number of hops of the relay link changes minimally compared to before the relay reselection, including:

[0078] The first device takes each relay device connected to the next-hop relay device of the first relay device as the target relay device in turn according to the principle that the total hop number changes from small to large, and performs relay reselection or link switching.

[0079] In an embodiment of the present application, the several relay devices behind the first relay device are regarded as a whole, and only the relay device of this hop is reselected to ensure that the total number of hops changes in the increasing direction to a minimum or the total number of hops remains unchanged. Among them, the relay devices connected to the next-hop relay device of the first relay device include: a relay device directly connected to the next-hop relay device of the first relay device and a relay device indirectly connected to the next-hop relay device of the first relay device (for example: connected by one hop, connected by N hops, N is an integer greater than 1). In the specific implementation, in order to ensure that the total number of hops changes from small to large, the relay device directly connected to the next-hop relay device of the first relay device is given priority as the target relay device to perform relay reselection, and the total number of hops remains unchanged; secondly, the relay device indirectly connected to the next-hop relay device of the first relay device is considered as the target relay device, and the total number of hops increases. It can be understood that the value of the increase in the total number of hops is the same as the number of hops corresponding to the indirect connection. For example, if a relay device connected to the next-hop relay device of the first relay device by one hop is used as the target relay device, the total number of hops increases by one hop. Wherein, being the target relay device means that the target relay device is selected as a device, and if the target device supports being a relay device, a communication link is established based on the target relay device.

[0080] For example, Figure 5 As shown, when the link situation between the first device UE2 and the first relay device UE3 triggers relay reselection, UE4 is the next-hop relay device of the first relay device, UE Z and UE X are relay devices directly connected to UE4, and UE Y is a relay device indirectly connected to UE4 (connected by one hop). In order to ensure that the total number of hops changes from small to large, the first device UE2 first considers selecting UE Z and UE X as target relay devices (the total number of hops remains unchanged at this time), and secondly, UE Y is selected as the target relay device (the total number of hops increases by one hop at this time).

[0081] In a specific embodiment, the method further comprises:

[0082] The first device determines whether a PC5 unicast connection establishment process, a mode-B discovery process, or a fusion discovery process initiated to a next-hop relay device of the first relay device is successfully executed;

[0083] The first device sequentially selects each relay device connected to the next-hop relay device of the first relay device as a target relay device according to the principle that the total hop number changes from small to large, and performs relay reselection or link switching, including:

[0084] In the event that the PC5 unicast connection establishment process, the mode-B discovery process, or the fusion discovery process initiated to the next-hop relay device of the first relay device fails, the first device, in accordance with the principle of the total number of hops changing from small to large, takes each relay device connected to the next-hop relay device of the first relay device as the target relay device, and performs relay reselection or link switching.

[0085] In the embodiment of the present application, the first device first attempts to initiate any one of the processes from B-1 to B-3 to the next-hop relay device of the first relay device to perform relay reselection. If the initiation of any one of the processes from B-1 to B-3 to the next-hop relay device of the first relay device fails, resulting in relay reselection failure or link switching failure, then further attempts to use each relay device connected to the next-hop relay device of the first relay device as the target relay device, and perform relay reselection or link switching. That is, the first device first attempts to perform a relay reselection that reduces the total number of hops by one and has the largest number of identical relay devices in the relay link compared to before the relay reselection. If the relay reselection fails or the link switching fails, then further attempts to perform a relay reselection or link switching that keeps the total number of hops unchanged or increases.

[0086] In a specific implementation manner, the first device sequentially selects each relay device connected to the next-hop relay device of the first relay device as a target relay device according to the principle that the total hop number changes from small to large, and performs relay reselection or link switching, including:

[0087] The first device uses a third relay device as a target relay device and performs relay reselection, wherein the third relay device is a relay device directly connected to a next-hop relay device of the first relay device;

[0088] When the first device fails to perform relay reselection or link switching based on the third relay device, the first device will, in accordance with the principle of total hop number change from small to large, take each relay device indirectly connected to the next-hop relay device of the first relay device as the target relay device, and perform relay reselection or link switching until the first device successfully reselects the relay or successfully switches the link. The first device successfully reselects the relay or successfully switches the link, which means that the first device has determined a device that supports being a relay device.

[0089] In the embodiment of the present application, in order to ensure that the total number of hops changes to a minimum, it is prioritized to determine whether the relay device (i.e., the third relay device) directly connected to the next-hop device of the first relay device supports being a relay device. If supported, a relay link of "first device" - "third relay device" - "next-hop relay device of the first relay device" is established, and the total number of hops remains unchanged. If not supported, a relay device indirectly connected to the next-hop device of the first relay device is selected as the target relay device to perform relay reselection or link switching, that is, a relay link of "first device" - "indirectly connected relay device" - "directly connected relay device" - "next-hop relay device of the first relay device" is established, and the total number of hops increases. For example, if a relay device connected to the next-hop relay device of the first relay device by one hop is used as the target relay device, the total number of hops increases by one hop.

[0090] For example, Figure 5 As shown, when the link situation between the first device UE2 and the first relay device UE3 triggers relay reselection or link switching, UE4 is the next-hop relay device of the first relay device, UE Z and UE X are relay devices directly connected to UE4, and UE Y is a relay device indirectly connected to UE4 (connected by one hop). In order to ensure that the total number of hops changes from small to large, the first device UE2 gives priority to selecting UE Z and UE X as target relay devices. If UE Z or UE X supports being a relay device, a relay link of UE2-UE Z / UE X-UE4 is established to replace UE2-UE3-UE4 before relay reselection. If neither UE Z nor UE X supports being a relay device, UE Y is selected as the target relay device to perform relay reselection or link switching; if UE Y supports being a relay device, a relay link of UE2-UE Y-UE Z-UE4 is established to replace UE2-UE3-UE4 before relay reselection; if UE Y does not support being a relay device, other relay devices indirectly connected to UE4 (for example, a relay device connected to UE4 through two hops) are selected as the target relay device to perform relay reselection or link switching.

[0091] Based on the method provided by the implementation of this application, the relay devices of several hops behind the first relay device are regarded as a whole, and only the relay devices of this hop are reselected, and the relay device directly connected to the next hop relay device of the first relay device is selected to replace the first relay device to ensure that the total number of hops remains unchanged; the relay device indirectly connected to the next hop relay device of the first relay device is selected to replace the first relay device to increase the total number of hops. Since not all relay devices are reselected, the link of relay communication can be quickly established, ensuring the efficiency and quality of communication.

[0092] In a specific implementation manner, the first device performs relay reselection or link switching based on the minimum total hop number of the relay link, including:

[0093] The first device determines a result of a second PC5 RSRP measured between the first device and the target remote terminal, and when the result of the second PC5 RSRP is greater than or equal to a second threshold, the first device initiates any one of the following processes to the target remote terminal:

[0094] Item B-1: PC5 unicast connection establishment process;

[0095] Item B-2: mode-B discovery process;

[0096] Item B-3: Integrated discovery process.

[0097] In the embodiment of the present application, the target remote terminal represents a remote terminal or a base station at the opposite end of the remote terminal. For example, Figure 6 The remote UE B and the base station in the communication protocol can both be used as the target remote terminal. When the link condition between the first device and the first relay device triggers relay reselection, in order to ensure that the total number of hops of the relay link is minimized, the target remote terminal is used as the target remote end similar to a single hop, and when the result of the second PC5 RSRP measured between the target remote terminals is greater than or equal to the second threshold, any one of the processes from B-1 to B-3 is initiated to the target remote terminal to achieve relay reselection or link switching, wherein the second threshold is set according to the actual relay communication link condition. Specifically, if the first device can determine that UE X is supported as a relay device, a plurality of relay devices before relay reselection are replaced by UE X is established.

[0098] For example, Figure 6 As shown, when the relay reselection is triggered due to the link condition between the first device UE2 and the first relay device UE3, the first device UE2 and the target remote terminal (remote UE B and base station) directly establish a PC5 unicast connection, and if it is found that there is a UE X that supports being a relay device, UE X is used to replace UE3-UE4-UE5. A relay device is used to replace multiple relay devices before the relay reselection, thereby reducing the total number of hops of the relay link as a whole.

[0099] In a specific implementation manner, the first device performs relay reselection or link switching based on the minimum total hop number of the relay link, including:

[0100] The first device takes each relay device in the relay link as the target remote terminal in turn according to the principle of total hop number from small to large, and performs relay reselection or link switching.

[0101] In an embodiment of the present application, in order to ensure that the total number of hops in the relay link is minimized, the first device takes each relay device in the relay link as the target remote terminal in turn according to the principle of total hops from small to large, and performs relay reselection or link switching.

[0102] For example, Figure 6 As shown, the relay devices in the relay link include UE1, UE2, UE3, UE4, and UE5. When the relay reselection is triggered due to the link condition between the first device UE2 and the first relay device UE3, UE5, UE4, and UE3 are used as target remote terminals in turn to perform relay reselection or link switching. For the detailed process, please refer to Example 3 below.

[0103] In a specific embodiment, the method further comprises:

[0104] The first device determines whether the PC5 unicast connection establishment process, the mode-B discovery process, or the fusion discovery process initiated to the target remote terminal is successfully executed;

[0105] The first device sequentially selects each relay device in the relay link as a target remote terminal according to the principle of the total hop number from small to large, and performs relay reselection or link switching, including:

[0106] In the event that the PC5 unicast connection establishment process, the mode-B discovery process, or the fusion discovery process initiated to the target remote terminal fails, the first device, in accordance with the principle of total hop number from small to large, takes each relay device in the relay link as the target remote terminal in turn, and performs relay reselection or link switching until the first device relay reselection succeeds or the link switching succeeds. The first device relay reselection success means that the first device determines a device that supports being a relay device.

[0107] In the embodiment of the present application, the first device first attempts to initiate any one of the processes from B-1 to B-3 to the target remote terminal to perform relay reselection or link switching. If the initiation of any one of the processes from B-1 to B-3 to the target remote terminal fails, resulting in relay reselection failure or link switching failure, then further attempts to use the previous hop relay device of the target remote terminal as the target remote terminal, and perform relay reselection or link switching. For the detailed process, please see Example 3 below.

[0108] In a specific implementation manner, a device that supports being a relay device refers to a device whose PC5 RSRP measurement result is not less than a corresponding threshold value; a device that does not support being a relay device refers to a device whose PC5 RSRP measurement result is less than the corresponding threshold value.

[0109] In the embodiment of the present application, the PC5 RSRP measurement result can reflect the quality of the communication link. Therefore, whether the relay device supports being a relay device is determined according to the PC5 RSRP measurement result. For example, Figure 4 As shown, when the link condition between UE2 and UE3 triggers relay reselection, if UE2 uses UE5 as the target relay device, it is determined whether UE5 supports being a relay device according to the PC5 RSRP measurement result between UE2 and UE5.

[0110] In a specific implementation manner, the first device is a second relay device; the second relay device may also notify other devices to perform relay reselection. Specifically, the method further includes:

[0111] In the case where relay reselection is triggered due to the link condition between the first device and the first relay device, the first device sends indication information to the previous hop relay device of the first device, or

[0112] When relay reselection is triggered due to the link condition between the first device and the first relay device, the first device sends indication information to the remote terminal.

[0113] In an embodiment of the present application, when the link condition between the first device and the first relay device triggers relay reselection, the first device does not perform relay reselection or link switching, but sends indication information to the previous-hop relay device or remote terminal of the first device to trigger the previous-hop relay device of the first device to perform relay reselection or link switching, or to trigger the remote terminal to perform relay reselection or link switching. In one embodiment, when there are other relay devices between the second relay device and the remote terminal, the indication information sent to the remote terminal is forwarded to the remote terminal via the other relay devices between the first device and the remote terminal.

[0114] For example, Figure 4 As shown, when relay reselection is triggered due to the link situation between the first device UE2 and the first relay device UE3, in one embodiment, the first device UE2 can send a relay reselection indication to the previous-hop relay device UE1, so that UE1 performs relay reselection or link switching; in another embodiment, UE2 can send a relay reselection indication to the remote terminal remote UE A through forwarding by UE1, so that remote UE A performs relay reselection or link switching.

[0115] In a specific implementation, when relay reselection is triggered due to a link condition between a first device and a first relay device, the first device sends indication information to a previous hop relay device of the first device, or the first device sends indication information to the remote terminal, including:

[0116] When relay reselection is triggered due to the link condition between the first device and the first relay device, and the relay reselection of the first device fails or the link switching fails, the first device sends indication information to the previous hop relay device of the first device, or the first device sends indication information to the remote terminal;

[0117] The relay reselection failure or link switching failure of the first device means that the first device has not determined a device that supports being a relay device.

[0118] In an embodiment of the present application, when the link status between the first device and the first relay device triggers relay reselection, the first device first performs relay reselection or link switching. If the relay reselection or link switching of the first device fails, that is, the first device has not determined a device that supports serving as a relay device, the previous-hop relay device or the remote terminal of the first device is notified to perform relay reselection or link switching.

[0119] For example, Figure 4 As shown, when the link status between the first device UE2 and the first relay device UE3 triggers relay reselection, UE2 first performs relay reselection or link switching. When UE2 has not determined a device that supports serving as a relay device, it sends a relay reselection indication to the previous-hop relay device UE1, or, through forwarding by UE1, sends a relay reselection indication to the remote terminal remote UE A.

[0120] In a specific implementation manner, the first device sending a relay reselection indication to the remote terminal includes:

[0121] In the case where the first device is directly connected to the remote terminal, the first device directly sends indication information to the remote terminal;

[0122] In a case where a fourth relay device is connected between the first device and the remote terminal, the first device sends indication information to the remote terminal via the fourth relay device.

[0123] In the embodiment of the present application, the first device is the second relay device, and the first device is directly connected to the remote terminal, indicating that there is no other relay device between the first device and the remote terminal, so the first device directly sends the relay reselection indication to the remote terminal. In the case where there is another relay device (i.e., a fourth relay device) between the first device and the remote terminal, the first device sends the relay reselection indication to the remote terminal through the fourth relay device.

[0124] For example, Figure 4As shown, when UE1 is the first device, UE1 directly sends a relay reselection indication to the remote terminal remote UE A. When UE2 is the first device, the first device UE2 sends a relay reselection indication to the remote terminal remote UE A through the fourth relay device UE1.

[0125] In a specific embodiment, it also includes:

[0126] In the case that the first device is the second relay device, a relay reselection indication sent by a fifth relay device is received, and the fifth relay device is a next-hop relay device of the second relay device before performing relay reselection.

[0127] For example, Figure 4 As shown, UE1 is the second relay device, and UE2 is the fifth relay device. When the link condition between the fifth relay device UE2 and the first relay device UE3 triggers relay reselection, the fifth relay device UE2 may not perform relay reselection, but send a relay reselection indication to the second relay device UE1, and then the second relay device UE1 performs relay reselection after receiving the relay reselection indication.

[0128] In a specific embodiment, it also includes:

[0129] In the case that the first device is a remote terminal, a relay reselection indication sent by a sixth relay device is received, and the sixth relay device is the next-hop relay device of the remote terminal before performing relay reselection.

[0130] For example, Figure 4 As shown, remote UE A is a remote terminal, and UE1 is a sixth relay device. In one example, when the link condition between the sixth relay device UE1 and the first relay device UE2 triggers relay reselection, the sixth relay device UE1 may not perform relay reselection, but send a relay reselection indication to remote UE A, and then remote UE A performs relay reselection after receiving the relay reselection indication. In another example, when the sixth relay device UE1 receives a relay reselection indication sent by other relay devices (for example: UE2), it forwards it to remote UE A, and then remote UE A performs relay reselection after receiving the relay reselection indication.

[0131] In a specific implementation manner, before the first device performs relay reselection or link switching, the process further includes obtaining at least one of the following information used for performing relay reselection or link switching:

[0132] Item D-1: Obtain the number of hops from each relay device to the target remote terminal;

[0133] Item D-2: Obtain routing information from each relay device to the target remote terminal.

[0134] In the embodiment of the present application, relay reselection or link switching is performed based on the relay reselection information. In order to ensure the smooth execution of relay reselection, the relay information of the relay device needs to be obtained before the first device performs relay reselection. Each relay device refers to a relay device between a remote terminal and a target remote terminal, such as Figure 4 As shown, the relay devices include five relay devices from UE1 to UE5. It is then necessary to obtain the number of hops from each relay device to the target remote terminal. For example, for UE1, the number of hops from UE1 to remote UE B or the base station is 5. The routing information from each relay device to the target remote terminal is to obtain the link between each relay device and the target remote terminal. For example, for UE2, UE2 forms a link through UE3, UE4, and UE5.

[0135] In a specific embodiment, the method further comprises:

[0136] Obtaining priority configuration information for relay reselection mode or link switching;

[0137] A target relay reselection mode or a target link switching mode is determined according to the priority configuration information, and the target relay reselection mode or the target link switching mode is any one of the following:

[0138] Item E-1: The number of identical relay devices in the relay link is the highest compared to before relay reselection;

[0139] Item E-2: The total number of hops of the relay link changes minimally compared to before the relay reselection;

[0140] Item E-3: The total number of hops in the relay link is the smallest.

[0141] In an embodiment of the present application, the first device may perform relay reselection based on a target relay reselection mode or a target link switching mode, and the target relay reselection mode or the target link switching mode is determined according to priority configuration information. The target relay reselection mode with the highest priority is preferentially selected for relay reselection, and the target link switching mode with the highest priority is preferentially selected for link switching. In the event that relay reselection fails according to the target relay reselection mode with the highest priority, relay reselection is continued according to the target relay reselection mode with the second highest priority. For example, the target relay reselection modes corresponding to the above items E-1 to E-3 have a priority order from high to low of E-2, E-1, and E-3, and relay reselection is preferentially performed according to the target relay reselection mode of item E-2.

[0142] The relay reselection method proposed in the above embodiment is described through the following embodiments.

[0143] Embodiment 1

[0144] In the scenario of U2U or U2N with multi-hop connection described in the first embodiment, the first device is the second relay device. When the relay reselection is triggered due to the link condition between the second relay device and the first relay device, the relay reselection is performed based on the relay reselection mode in which the total number of hops of the relay link is changed minimally compared with before the relay reselection. The specific steps are as follows:

[0145] Step 1: The first device determines the result of the first PC5 RSRP measured between the first device and the next-hop relay device of the first relay device. When the result of the first PC5 RSRP is greater than or equal to a first threshold, the first device initiates one of the following processes to the next-hop relay device of the first relay device: PC5 unicast connection establishment process; or mode-B discovery process; or fusion discovery process;

[0146] Step 2: When the PC5 unicast connection establishment process, mode-B discovery process, or converged discovery process initiated to the next-hop relay device of the first relay device fails, the first device determines whether the third relay device supports being a relay device, and the third relay device is a relay device directly connected to the next-hop relay device of the first relay device;

[0147] Step 3: In the case where the first device fails to perform relay reselection based on the third relay device, each relay device indirectly connected to the next-hop relay device of the first relay device is sequentially selected as a target relay device according to the principle of the total hop number changing from small to large, and relay reselection is performed until the first device relay reselection succeeds, and the first device relay reselection success means that the first device determines a device that supports being a relay device;

[0148] Step 4: According to the principle that the total number of hops changes from small to large, each relay device indirectly connected to the next-hop relay device of the first relay device is taken as the target relay device in turn, and when relay reselection fails, the first device sends a relay reselection indication to the previous-hop relay device of the first device, or the first device sends a relay reselection indication to the remote terminal.

[0149] In an embodiment of the present application, in order to ensure that the total number of hops of the relay link changes to the minimum, the first device performs relay reselection in the order of the minimum change in the total number of hops in the decreasing direction, the constant total number of hops, and the minimum change in the total number of hops in the increasing direction. First, the first device performs relay reselection with the next-hop relay device of the first relay device as the target relay device, and the total number of hops is reduced by one hop. In the event that relay reselection fails with the next-hop relay device of the first relay device as the target relay device, the first device determines whether the third relay device supports being a relay device. When the third relay device supports being a relay device, the third relay device is selected to replace the first relay device before relay reselection, and a relay link of "first device" - "third relay device" - "next-hop relay device of the first relay device" is established, and the total number of hops remains unchanged. If not supported, a relay device indirectly connected to the next-hop device of the first relay device is selected as the target relay device to perform relay reselection or link switching, that is, to establish a relay link of "first device" - "indirectly connected relay device" - "directly connected relay device" - "next-hop relay device of the first relay device", and the total number of hops increases. For example, if a relay device connected to the next-hop relay device of the first relay device by one hop is selected as the target relay device, the total number of hops increases.

[0150] For example, Figure 5As shown, when the link situation between the first device UE2 and the first relay device UE3 triggers relay reselection or link switching, UE4 is the next-hop relay device of the first relay device, UE Z and UE X are relay devices directly connected to UE4, and UE Y is a relay device indirectly connected to UE4 (connected by one hop). The first device UE2 preferentially tries to establish a connection with UE4, and the total number of hops is reduced by one hop. If UE2 fails to connect to UE4, UE2 uses UE Z and UE X directly connected to UE4 as target relay devices for relay reselection. If UE Z or UE X supports being a relay device, a relay link of UE2-UE Z / UE X-UE4 is established to replace UE2-UE3-UE4 before relay reselection, and the total number of hops remains unchanged. If neither UE Z nor UE X supports being a relay device, then the indirectly connected UE Y is used as the target relay device to perform relay reselection; if UE Y supports being a relay device, then a relay link of UE2-UE Y-UE Z-UE4 is established to replace UE2-UE3-UE4 before relay reselection, and the total number of hops increases by one hop. If UE Y does not support being a relay device, then another relay device indirectly connected to UE4 (for example, a relay device connected to UE4 through two hops) is selected as the target relay device to perform relay reselection. If a device that supports being a relay device cannot be determined based on the relay device indirectly connected to UE4, UE2 notifies UE1 and / or remote UE A so that UE1 and / or remote UE A performs relay reselection.

[0151] Embodiment 2

[0152] In the scenario of U2U or U2N with multi-hop connection described in the second embodiment, the first device is a second relay device. When relay reselection is triggered due to the link condition between the first device and the first relay device, relay reselection is performed based on the relay reselection mode with the smallest total number of hops of the relay link. The specific steps are as follows:

[0153] Step 1: The first device determines whether the PC5 unicast connection establishment process, the mode-B discovery process, or the fusion discovery process initiated to the target remote terminal is successfully executed. For example, the first device determines whether there is a fourth relay device that supports serving as a relay device during the process of directly establishing a PC5 unicast connection with the target remote terminal;

[0154] Step 2: In the case where the fourth relay device exists, the first device selects the fourth relay device;

[0155] Step 3: When the PC5 unicast connection establishment process, mode-B discovery process, or fusion discovery process initiated to the target remote terminal fails, that is, when the fourth relay device does not exist, the first device sequentially selects each relay device in the relay link as the target remote terminal according to the principle of the total number of hops from small to large, and performs relay reselection until the first device relay reselection succeeds, and the first device relay reselection success means that the first device determines the device that supports being a relay device;

[0156] Step 4: In case the relay reselection of the first device fails, the first device sends a relay reselection indication to the previous-hop relay device of the first device, or the first device sends a relay reselection indication to the remote terminal.

[0157] In the embodiment of the present application, in order to ensure that the total number of hops of the relay link is minimized, the target remote terminal is preferentially considered as the target remote terminal similar to the single hop for relay reselection, and if there is a fourth relay device that supports being a relay device, the fourth relay device is used to replace the multiple relay devices before the corresponding relay reselection. If there is no fourth relay device, the first device sequentially selects each relay device in the relay link as the target remote terminal according to the principle of the total number of hops from small to large, and performs relay reselection.

[0158] For example, Figure 6 As shown, the relay devices in the relay link include UE1, UE2, UE3, UE4, and UE5. When the link condition between the first device UE2 and the first relay device UE3 triggers relay reselection, the base station or remote UE B is preferentially used as the target remote terminal for relay reselection. If there is a fourth relay device UE X, UE X is used to replace UE3-UE4-UE5. If there is no fourth relay device, UE5, UE4, and UE3 are used as target remote terminals in turn to perform relay reselection until a relay device that meets the requirements of supporting as a relay device is selected. If the relay device that supports being a relay device cannot be determined according to the above method, UE2 notifies UE1 and / or remote UE A so that UE1 and / or remote UE A performs relay reselection.

[0159] Embodiment 3

[0160] In the scenario of U2U or U2N of multi-hop connection described in the third embodiment, the first device is a second relay device, and the first device sends a relay reselection indication to the remote terminal so that the remote terminal performs relay reselection. The specific steps are as follows:

[0161] Step 1: When relay reselection is triggered due to a link condition between a first device and a first relay device, the first device sends indication information to the remote terminal to trigger the remote terminal to perform relay reselection;

[0162] Step 2: The remote terminal obtains at least one of the following information for relay reselection: obtaining hop count information from each relay device to the target remote terminal; obtaining routing information from each relay device to the target remote terminal;

[0163] Step 3: The remote terminal obtains the priority configuration information of the relay reselection mode;

[0164] Step 4: The remote terminal determines a target relay reselection mode according to the priority configuration information, wherein the target relay reselection mode is any one of the following: compared with before the relay reselection, the same number of relay devices in the relay link is the largest; compared with before the relay reselection, the total number of hops of the relay link changes the least; the total number of hops of the relay link is the smallest;

[0165] Step 5: The remote terminal performs relay reselection according to the target relay reselection method.

[0166] In the embodiment of the present application, when the link condition between the first device and the first relay device triggers relay reselection, the first device does not perform relay reselection, but triggers the remote terminal to perform relay reselection by sending indication information. The remote terminal does not know the relay device information of each relay device between the remote terminal and the target remote terminal in advance, so after the remote terminal receives the relay reselection indication sent by the first device, it first obtains the relay device information used for relay reselection, and also obtains the priority configuration information, so as to subsequently determine the target relay reselection mode according to the priority configuration information, and perform relay reselection based on the target relay reselection mode and the relay device information.

[0167] Second, see Figure 7 , Figure 7 A schematic diagram of the structure of a relay reselection system provided in an embodiment of the present application is shown. Figure 7 As shown, the relay reselection system 700 includes: a first device 710, a first relay device 720;

[0168] The first device 710 is configured to, when relay reselection is triggered due to a link condition between the first device and the first relay device, perform relay reselection or link switching based on any one of the following:

[0169] Compared with before relay reselection, the number of identical relay devices in the relay link is the largest;

[0170] Compared with before relay reselection, the total number of hops of the relay link changes minimally;

[0171] The total number of hops in the relay link is minimal;

[0172] The first device is a remote terminal or a second relay device, and the value of the total number of hops is equal to the total number of relay devices in the relay link, or the value of the total number of hops is equal to the total number of relay devices in the relay link plus 1.

[0173] Optionally, the relay reselection system 700 further includes a target remote terminal 730; the target remote terminal 730 sends priority configuration information of the relay reselection mode or link switching to the first device;

[0174] The first device determines the target relay reselection mode or the target link switching mode according to the priority configuration information, and the target relay reselection mode or the target link switching mode is any one of the following:

[0175] Compared with before relay reselection, the number of identical relay devices in the relay link is the largest;

[0176] Compared with before relay reselection, the total number of hops of the relay link changes minimally;

[0177] The total number of hops of the relay link is minimal.

[0178] Based on the relay reselection system provided by the embodiment of the present application, when the relay reselection is triggered due to the link situation between the first device and the first relay device, the first device performs relay reselection or link switching based on any one of the following: compared with before the relay reselection, the number of identical relay devices in the relay link is the largest; compared with before the relay reselection, the total number of hops in the relay link changes the least; the total number of hops in the relay link is the smallest; wherein the first device is a remote terminal or a second relay device, and the value of the total number of hops is equal to the total number of relay devices in the relay link, or the value of the total number of hops is equal to the total number of relay devices in the relay link plus 1. In this way, relay reselection can be performed when the link triggers the relay reselection condition, so that relay communication can be performed based on the reselected relay device in the future, ensuring the efficiency and quality of communication.

[0179] In a specific implementation, the first device performs relay reselection or link switching based on the fact that the total number of hops of the relay link changes minimally compared to before the relay reselection, including:

[0180] The first device determines a result of a first PC5 RSRP measured between the first device and a next-hop relay device of the first relay device, and when the result of the first PC5 RSRP is greater than or equal to a first threshold, the first device initiates one of the following processes to the next-hop relay device of the first relay device:

[0181] PC5 unicast connection establishment process; or

[0182] mode-B discovery process; or

[0183] Fusion discovery process.

[0184] In a specific implementation, the first device performs relay reselection or link switching based on the largest number of identical relay devices in the relay link compared to before the relay reselection, including:

[0185] The first device uses the next-hop relay device of the first relay device as a target remote device, and performs relay reselection or link switching.

[0186] In a specific implementation, the first device performs relay reselection or link switching based on the fact that the total number of hops of the relay link changes minimally compared to before the relay reselection, including:

[0187] The first device takes each relay device connected to the next-hop relay device of the first relay device as the target relay device in turn according to the principle that the total hop number changes from small to large, and performs relay reselection or link switching.

[0188] In a specific implementation manner, the first device determines whether a PC5 unicast connection establishment process, a mode-B discovery process, or a fusion discovery process initiated to a next-hop relay device of the first relay device is successfully executed;

[0189] When the first device fails to initiate a PC5 unicast connection establishment process, a mode-B discovery process, or a fusion discovery process to the next-hop relay device of the first relay device, the first device will, in accordance with the principle of the total number of hops changing from small to large, take each relay device connected to the next-hop relay device of the first relay device as the target relay device and perform relay reselection or link switching.

[0190] In a specific implementation, the system further includes a third relay device;

[0191] The first device uses a third relay device as a target relay device and performs relay reselection or link switching, wherein the third relay device is a relay device directly connected to a next-hop relay device of the first relay device;

[0192] When the first device fails to perform relay reselection or link switching based on the third relay device, the first device will, in accordance with the principle of total hop number change from small to large, take each relay device indirectly connected to the next-hop relay device of the first relay device as the target relay device, and perform relay reselection or link switching until the first device successfully reselects the relay or successfully switches the link. The first device successfully reselects the relay or successfully switches the link, which means that the first device has determined a device that supports being a relay device.

[0193] In a specific implementation manner, the first device performs relay reselection or link switching based on the minimum total hop number of the relay link, including:

[0194] The first device determines a result of a second PC5 RSRP measured between the first device and the target remote terminal, and when the result of the second PC5 RSRP is greater than or equal to a second threshold, the first device initiates one of the following processes to the target remote terminal:

[0195] PC5 unicast connection establishment process; or

[0196] mode-B discovery process; or

[0197] Fusion discovery process.

[0198] In a specific implementation manner, the first device performs relay reselection or link switching based on the minimum total hop number of the relay link, including:

[0199] The first device takes each relay device in the relay link as the target remote terminal in turn according to the principle of total hop number from small to large, and performs relay reselection or link switching.

[0200] In a specific implementation, the first device determines whether a PC5 unicast connection establishment process, a mode-B discovery process, or a fusion discovery process initiated to a target remote terminal is successfully executed;

[0201] The first device sequentially selects each relay device in the relay link as a target remote terminal according to the principle of the total hop number from small to large, and performs relay reselection or link switching, including:

[0202] In the event that the PC5 unicast connection establishment process, the mode-B discovery process, or the fusion discovery process initiated to the target remote terminal fails, the first device, in accordance with the principle of total hop number from small to large, takes each relay device in the relay link as the target remote terminal in turn, and performs relay reselection or link switching until the first device relay reselection succeeds or the link switching succeeds. The first device relay reselection success means that the first device determines a device that supports being a relay device.

[0203] In a specific implementation manner, the device supporting serving as a relay device refers to: a device whose PC5 RSRP measurement result is not less than a corresponding threshold value;

[0204] A device that is not supported as a relay device refers to a device whose PC5 RSRP measurement result is smaller than the corresponding threshold value.

[0205] In a specific embodiment, when relay reselection is triggered due to the link condition between the first device and the first relay device, the first device sends indication information to the previous-hop relay device of the first device, or when relay reselection is triggered due to the link condition between the first device and the first relay device, the first device sends indication information to the remote terminal.

[0206] In a specific implementation, when relay reselection is triggered due to the link condition between the first device and the first relay device, and the relay reselection of the first device fails or the link switching fails, the first device sends indication information to the previous hop relay device of the first device, or the first device sends indication information to the remote terminal;

[0207] The relay reselection failure or link switching failure of the first device means that the first device has not determined a device that supports being a relay device.

[0208] In a specific implementation, the system further includes a fourth relay device;

[0209] In the case where the first device is directly connected to the remote terminal, the first device directly sends indication information to the remote terminal;

[0210] In a case where a fourth relay device is connected between the first device and the remote terminal, the first device sends indication information to the remote terminal via the fourth relay device.

[0211] In a specific implementation, the system further includes a fifth relay device and a sixth relay device;

[0212] In the case where the first device is a second relay device, the indication information sent by the fifth relay device is received, and the fifth relay device is the next-hop relay device of the second relay device before performing relay reselection; or in the case where the first device is a remote terminal, the indication information sent by the sixth relay device is received, and the sixth relay device is the next-hop relay device of the remote terminal before performing relay reselection.

[0213] In a specific implementation manner, before the first device performs relay reselection or link switching, the process further includes obtaining at least one of the following information used for performing relay reselection or link switching:

[0214] Obtain the hop count information from each relay device to the target remote terminal;

[0215] Obtain routing information from each relay device to the target remote terminal.

[0216] like Figure 8 As shown, the embodiment of the present application further provides a device 800, including a processor 801 and a memory 802, and the memory 802 stores a program or instruction that can be run on the processor 801. For example, when the communication device 800 is a terminal, the program or instruction is executed by the processor 801 to implement the various steps of the above-mentioned information indication method embodiment, and can achieve the same technical effect. When the communication device 800 is a network side device, the program or instruction is executed by the processor 801 to implement the various steps of the above-mentioned relay reselection method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0217] The present application also provides a network side device, such as Fig. 9 As shown, the network side device 900 includes: an antenna 901, a radio frequency device 902, a baseband device 903, a processor 904 and a memory 905. The antenna 906 is connected to the radio frequency device 902. In the uplink direction, the radio frequency device 902 receives information through the antenna 901 and sends the received information to the baseband device 903 for processing. In the downlink direction, the baseband device 903 processes the information to be sent and sends it to the radio frequency device 902. The radio frequency device 902 processes the received information and sends it out through the antenna 901.

[0218] The information interaction between the network side device and the terminal in the above embodiments can be implemented in the baseband device 903, and the baseband device 903 includes a baseband processor.

[0219] The baseband device 903 may include, for example, at least one baseband board on which a plurality of chips are arranged. Fig. 9 As shown, one of the chips is, for example, a baseband processor, which is connected to the memory 905 through a bus interface to call the program in the memory 905 to execute the relay reselection operation shown in the above method embodiment.

[0220] The network side device may further include a network interface 906, which is, for example, a Common Public Radio Interface (CPRI).

[0221] Specifically, the network side device 900 of the embodiment of the present application further includes: an instruction or program stored in the memory 905 and executable on the processor 904, and the processor 904 calls the instruction or program in the memory 905 to execute Figure 3 The methods of each step shown in the figure achieve the same technical effect, and to avoid repetition, they will not be described here.

[0222] An embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the various processes of the above-mentioned information indication method embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0223] The processor is the processor in the terminal described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk. In some examples, the readable storage medium may be a non-transient readable storage medium.

[0224] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned information indication method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0225] 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.

[0226] The embodiments of the present application further provide a computer program / program product, which is stored in a storage medium and is executed by at least one processor to implement the various processes of the above-mentioned information indication method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0227] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises one..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the method and device in the embodiment of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0228] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of a computer software product plus a necessary general hardware platform, and of course, can also be implemented by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, disk, CD, etc.), including several instructions to enable a terminal or a network-side device to execute the methods described in each embodiment of the present application.

[0229] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms of implementation methods without departing from the purpose of the present application and the scope of protection of the claims, and these implementation methods are all within the protection of the present application.

Claims

1. A relay reselection method, characterized in that: include: In the case where relay reselection is triggered due to the link condition between the first device and the first relay device, the first device performs relay reselection or link switching based on any one of the following: Compared with before relay reselection, the number of identical relay devices in the relay link is the largest; Compared with before relay reselection, the total number of hops of the relay link changes minimally; The total number of hops in the relay link is minimal; The first device is a remote terminal or a second relay device, and the value of the total number of hops is equal to the total number of relay devices in the relay link, or the value of the total number of hops is equal to the total number of relay devices in the relay link plus 1.

2. The method according to claim 1, characterized in that The first device performs relay reselection or link switching based on that the total number of hops of the relay link changes minimally compared with before the relay reselection, including: The first device determines a result of a first PC5 RSRP measured between the first device and a next-hop relay device of the first relay device, and when the result of the first PC5 RSRP is greater than or equal to a first threshold, the first device initiates one of the following processes to the next-hop relay device of the first relay device: PC5 unicast connection establishment process; or mode-B discovery process; or Integrate the discovery process.

3. The method according to claim 1, characterized in that The first device performs relay reselection or link switching based on the fact that the number of identical relay devices in the relay link is the largest compared to before the relay reselection, including: The first device uses the next-hop relay device of the first relay device as a target remote device, and performs relay reselection or link switching.

4. The method according to claim 1, characterized in that The first device performs relay reselection or link switching based on that the total number of hops of the relay link changes minimally compared with before the relay reselection, including: The first device, in accordance with the principle that the total number of hops changes from small to large, sequentially selects each relay device connected to the next-hop relay device of the first relay device as a target relay device, and performs relay reselection or link switching.

5. The method according to claim 4, characterized in that The method further comprises: The first device determines whether a PC5 unicast connection establishment process, a mode-B discovery process, or a fusion discovery process initiated to a next-hop relay device of the first relay device is successfully executed; The first device sequentially selects each relay device connected to the next-hop relay device of the first relay device as a target relay device according to the principle that the total hop number changes from small to large, and performs relay reselection or link switching, including: In the event that the PC5 unicast connection establishment process, the mode-B discovery process, or the fusion discovery process initiated to the next-hop relay device of the first relay device fails, the first device, in accordance with the principle of the total number of hops changing from small to large, takes each relay device connected to the next-hop relay device of the first relay device as the target relay device, and performs relay reselection or link switching.

6. The method according to claim 4 or 5, characterized in that: The first device sequentially selects each relay device connected to the next-hop relay device of the first relay device as a target relay device according to the principle that the total hop number changes from small to large, and performs relay reselection or link switching, including: The first device uses a third relay device as a target relay device and performs relay reselection or link switching, wherein the third relay device is a relay device directly connected to a next-hop relay device of the first relay device; When the first device fails to perform relay reselection or link switching based on the third relay device, the first device will, in accordance with the principle of total hop number change from small to large, take each relay device indirectly connected to the next-hop relay device of the first relay device as the target relay device, and perform relay reselection or link switching until the first device successfully reselects the relay or successfully switches the link. The first device successfully reselects the relay or successfully switches the link, which means that the first device has determined a device that supports being a relay device.

7. The method according to claim 1, characterized in that The first device performs relay reselection or link switching based on the minimum total hop number of the relay link, including: The first device determines a result of a second PC5 RSRP measured between the first device and the target remote terminal, and when the result of the second PC5 RSRP is greater than or equal to a second threshold, the first device initiates one of the following processes to the target remote terminal: PC5 unicast connection establishment process; or mode-B discovery process; or Fusion discovery process.

8. The method according to claim 1, characterized in that The first device performs relay reselection or link switching based on the minimum total hop number of the relay link, including: The first device takes each relay device in the relay link as the target remote terminal in turn according to the principle of total hop number from small to large, and performs relay reselection or link switching.

9. The method according to claim 8, characterized in that The method further comprises: The first device determines whether the PC5 unicast connection establishment process, the mode-B discovery process, or the fusion discovery process initiated to the target remote terminal is successfully executed; The first device sequentially selects each relay device in the relay link as a target remote terminal according to the principle of the total hop number from small to large, and performs relay reselection or link switching, including: In the event that the PC5 unicast connection establishment process, the mode-B discovery process, or the fusion discovery process initiated to the target remote terminal fails, the first device, in accordance with the principle of total hop number from small to large, takes each relay device in the relay link as the target remote terminal in turn, and performs relay reselection or link switching until the first device relay reselection succeeds or the link switching succeeds. The first device relay reselection success means that the first device determines a device that supports being a relay device.

10. The method according to claim 6 or 9, characterized in that: Devices that can be used as relay devices are: devices whose PC5RSRP measurement results are not less than the corresponding threshold value; A device that is not supported as a relay device refers to a device whose PC5 RSRP measurement result is smaller than the corresponding threshold value.

11. The method according to any one of claims 1 to 10, wherein the first device is a second relay device; further comprising: In the case where relay reselection is triggered due to the link condition between the first device and the first relay device, the first device sends indication information to the previous hop relay device of the first device, or When relay reselection is triggered due to the link condition between the first device and the first relay device, the first device sends indication information to the remote terminal.

12. The method according to claim 11, characterized in that In a case where relay reselection is triggered due to a link condition between a first device and a first relay device, the first device sends indication information to a previous-hop relay device of the first device, or the first device sends indication information to the remote terminal, including: When relay reselection is triggered due to the link condition between the first device and the first relay device, and the relay reselection of the first device fails or the link switching fails, the first device sends indication information to the previous hop relay device of the first device, or the first device sends indication information to the remote terminal; The relay reselection failure or link switching failure of the first device means that the first device has not determined a device that supports being a relay device.

13. The method according to claim 11 or 12, characterized in that: The first device sending indication information to the remote terminal includes: In the case where the first device is directly connected to the remote terminal, the first device directly sends indication information to the remote terminal; In a case where a fourth relay device is connected between the first device and the remote terminal, the first device sends indication information to the remote terminal via the fourth relay device.

14. The method according to any one of claims 1 to 13, characterized in that: Also includes: In a case where the first device is a second relay device, receiving indication information sent by a fifth relay device, the fifth relay device being a next-hop relay device of the second relay device before relay reselection; or In the case that the first device is a remote terminal, indication information sent by a sixth relay device is received, and the sixth relay device is a next-hop relay device of the remote terminal before performing relay reselection.

15. The method according to any one of claims 1 to 14, characterized in that: Before the first device performs relay reselection or link switching, the method further includes obtaining at least one of the following information used for performing relay reselection or link switching: Obtain the hop count information from each relay device to the target remote terminal; Obtain routing information from each relay device to the target remote terminal.

16. The method according to any one of claims 1 to 15, characterized in that: The method further comprises: Obtaining priority configuration information for relay reselection mode or link switching; Determine a target relay reselection mode or a target link switching mode according to the priority configuration information, where the target relay reselection mode or the target link switching mode is any one of the following: Compared with before relay reselection, the number of identical relay devices in the relay link is the largest; Compared with before relay reselection, the total number of hops of the relay link changes minimally; The total number of hops of the relay link is minimal.

17. A relay reselection system, characterized in that: include: A first device, a first relay device; The first device is configured to, when relay reselection is triggered due to a link condition between the first device and the first relay device, perform relay reselection or link switching based on any one of the following: Compared with before relay reselection, the number of identical relay devices in the relay link is the largest; Compared with before relay reselection, the total number of hops of the relay link changes minimally; The total number of hops in the relay link is minimal; The first device is a remote terminal or a second relay device, and the value of the total number of hops is equal to the total number of relay devices in the relay link, or the value of the total number of hops is equal to the total number of relay devices in the relay link plus 1.

18. The system according to claim 17, characterized in that Also included is a target remote terminal; the target remote terminal sends priority configuration information of a relay reselection mode or a link switching to the first device; The first device determines the target relay reselection mode or the target link switching mode according to the priority configuration information, and the target relay reselection mode or the target link switching mode is any one of the following: Compared with before relay reselection, the number of identical relay devices in the relay link is the largest; Compared with before relay reselection, the total number of hops of the relay link changes minimally; The total number of hops of the relay link is minimal.

19. A device, characterized in that It comprises a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of the relay reselection method according to any one of claims 1 to 16 are implemented.

20. A readable storage medium, characterized in that: The readable storage medium stores a program or instruction, and when the program or instruction is executed by the processor, the steps of the relay reselection method according to any one of claims 1 to 16 are implemented.

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