WO2023070633A1

WO2023070633A1 - D2d communication method

Info

Publication number: WO2023070633A1
Application number: PCT/CN2021/127783
Authority: WO
Inventors: 邓猛; 于强; 沈秀勇; 王新柱
Original assignee: 华为技术有限公司
Priority date: 2021-10-30
Filing date: 2021-10-30
Publication date: 2023-05-04
Also published as: CN118176751A

Abstract

Embodiments of the present application provide a D2D communication method. The method comprises: receiving a first transfer UE information list sent by relay UE, the first transfer UE information list comprising path information of a first communication path from the relay UE to a target UE; and then, receiving heartbeat information sent by the relay UE, wherein the heartbeat information comprises a device identifier and a version number of the relay UE, and the version number is used for confirming whether the first transfer UE information list is an updated transfer UE information list; and when confirmed, on the basis of the first version number, that the first transfer UE information list is the updated transfer UE information list, sending first unicast information on the basis of the first transfer UE information list. In the described method, the communication state of the maintained target UE and the reliability of the communication path are improved.

Description

A D2D communication method

technical field

The present application relates to the technical field of communication, and in particular to a D2D communication method.

Background technique

With the development of smart phones, in order to meet the needs of users for different services, end-to-device (device to device, D2D) communication has become one of the research hotspots of 3GPP. D2D communication allows user equipment to communicate directly without forwarding messages through the base station for communication, which solves the problem that user equipment can communicate directly based on the D2D network in areas with poor coverage of cellular mobile signals or WLAN signals.

In the D2D network, the communication state of the user equipment will change dynamically. For example, the operation of the user equipment such as switching on and off will cause the communication state to change, and the location of the user equipment will also move dynamically, which will cause the user equipment in the D2D network. The communication paths among them are also changing dynamically. Therefore, how to improve and maintain the communication state of the user equipment in the D2D network and the reliability of the communication path is an urgent problem to be solved.

Contents of the invention

The embodiment of the present application provides a D2D communication method, which can improve the communication state of the target UE maintained by the UE and the reliability of the communication path.

In the first aspect, the embodiment of the present application provides a D2D communication method, the method includes:

receiving a first transfer UE information list sent by the first UE; wherein, the first transfer UE information list includes path information of a first communication path between the first UE and a second UE, and the second UE is a target UE; receiving The first heartbeat information sent by the first UE, the first heartbeat information includes the device identifier and the first version number of the first UE, and the first version number is used to confirm whether the first transfer UE information list is an updated transfer UE information list; when When it is confirmed based on the first version number that the first transfer UE information list is an updated transfer UE information list, the first unicast information is sent based on the first transfer UE information list.

Optionally, the first UE sends the first heartbeat information continuously (for example, 5s is a cycle).

Based on the method provided in the first aspect, the UE can confirm whether it is the latest transfer UE information list information received based on the version number contained in the received heartbeat information, which improves the communication status and communication path of the target UE maintained by the UE. reliability.

With reference to the first aspect, in a possible implementation manner, the method further includes: when it is confirmed based on the first version number that the first transfer UE information list is not an updated transfer UE information list, sending a first request to the first UE, the second A request is used to instruct the first UE to send an updated transfer UE information list; receive the updated transfer UE information list sent by the first UE, and the updated transfer UE information list includes the second communication path between the first UE and the third UE the path information; sending the first unicast information based on the updated transit UE information list.

The third UE may be the same as or different from the second UE.

The method for confirming that the first transfer UE information list is not an updated transfer UE information list based on the first version number may include: when the first transfer UE information list also includes the second version number, if the second version number is the same as the first version number If they are different, it is determined that the first transfer UE information list is not the latest transfer UE information list. Or, when the first relay UE information list does not include the second version number, before receiving the first relay UE information list, the second heartbeat information is also received, and the second heartbeat information includes the third version number and the first UE's Equipment Identity. Optionally, the second heartbeat information is heartbeat information adjacent to the first relay UE information list. When the second version number is different from the third version number, it is determined that the first transfer UE information list is not the latest transfer UE information list.

It can be seen that, when it is determined that the first transfer UE information list is not the latest transfer UE information list, a first request may be sent to the first UE, where the first request is used to obtain the latest transfer UE information list. In this way, the reliability of the received transfer UE information list is improved, and the accuracy of subsequent updating of the communication state and communication path of the target UE based on the transfer UE information list is ensured.

With reference to the first aspect, in a possible implementation manner, sending the first request to the first UE includes: after receiving the first heartbeat information and reaching the first time, the updated transfer UE information list has not yet been received, and sending the first request to the first UE A UE sends a first request. In this way, after it is determined that the first transfer UE information list is not the latest transfer UE information list, wait for the first time before sending the request, so as to avoid the problem of repeated sending due to network delay.

With reference to the first aspect, in a possible implementation manner, the first relay UE information list includes a second version number; the method further includes: comparing the first version number and the second version number, so as to confirm the first version number based on the first version number. The transfer UE information list is an updated transfer UE information list. When the first version number is the same as the second version number, it is confirmed that the first transfer UE information list is an updated transfer UE information list.

With reference to the first aspect, in a possible implementation manner, the first relay UE information list does not include a version number. Comparing the first version number and the third version number, if the first version number and the third version number are the same, confirm that the first transfer UE information list is an updated transfer UE information list.

With reference to the first aspect, in a possible implementation manner, after receiving the first heartbeat information sent by the first UE, the method further includes: not receiving an updated heartbeat message sent by the first UE within a second time, sending the The communication state in the communication path passing through the first UE is changed from on-net to off-net, or the communication state in the communication path with the first UE as the next-hop UE is changed from on-net to off-net. In this way, when the updated heartbeat message sent by the first UE cannot be received, it is impossible to directly communicate with the first UE, and the communication status of the first UE is changed from on-net to off-net, or the first UE The communication status in the communication path of the UE as the next hop UE is changed from on-net to off-net. In this way, the communication state of the target UE can be updated in real time.

With reference to the first aspect, in a possible implementation manner, after receiving the second heartbeat message sent by the first UE, before receiving the first transit UE information list sent by the first UE, the method further includes: after receiving Before the second heartbeat message, the first transit UE information list is not received, and the first transit UE information list is not received at the third time after receiving the second heartbeat message, that is, the heartbeat message including the version number can be received, However, if the relay UE information list sent by the first UE has never been received, a second request is sent to the first UE, and the second request is used to instruct the first UE to send the first relay UE information list.

With reference to the first aspect, in a possible implementation manner, the first relay UE information list further includes the communication state of the second UE, the number of transfer hops for data transmission in the first communication path, and the first The device identifier UEID of the UE's next hop UE. Wherein, the communication state includes an on-net state or an off-net state. The online state is used to indicate that the second UE is in the power-on state, and further, the second UE in the power-on state can directly communicate with other UEs or indirectly communicate with other UEs by forwarding data through the Relay UE. The off-grid state is a power-off state, and further, the second UE in the power-off state cannot directly communicate with other UEs or indirectly communicate with other UEs by forwarding data through the Relay UE.

With reference to the first aspect, in a possible implementation manner, the first relay UE information list further includes the networking identifier of the second UE. The networking identifier is used to indicate whether the second UE has established a connection with the base station or has not established a connection with the base station.

In combination with the first aspect, in a possible implementation manner, after receiving the first transit UE information list sent by the first UE, it can also be considered that the first heartbeat message sent by the first UE is not received before a certain time. If the first transfer UE information list is the latest, then the first unicast message may be sent based on the first transfer UE information list. After a certain period of time, if the first heartbeat message sent by the first UE is still not received, the first unicast message is not sent based on the first relay UE information list.

In a second aspect, the embodiment of the present application provides a communication device. Including: a receiving unit, configured to receive a first transfer UE information list sent by the first UE; wherein, the first transfer UE information list includes path information of a first communication path between the first UE and the second UE, and the second UE It is the target UE; the receiving unit is also used to receive the first heartbeat information sent by the first UE, the first heartbeat information includes the device identifier and the first version number of the first UE, and the first version number is used to confirm the first transit UE information Whether the list is an updated transfer UE information list; the sending unit is configured to send the first unicast information based on the first transfer UE information list when it is confirmed based on the first version number that the first transfer UE information list is an updated transfer UE information list .

With reference to the second aspect, in a possible implementation manner, the sending unit is further configured to send the first request to the first UE when it is confirmed based on the first version number that the first transfer UE information list is not an updated transfer UE information list The first request is used to instruct the first UE to send an updated transfer UE information list; the receiving unit is also used to receive the updated transfer UE information list sent by the first UE, and the updated transfer UE information list includes the first UE to the third Path information of the second communication path between UEs; a sending unit, further configured to send the first unicast information based on the updated relay UE information list.

With reference to the second aspect, in a possible implementation manner, the sending unit is further configured to send the first UE information list to the first UE when the first time is reached after receiving the first heartbeat information and the updated transfer UE information list has not yet been received. one request.

With reference to the second aspect, in a possible implementation manner, the first relay UE information list includes a second version number; the communication device further includes a processing unit; wherein the processing unit is configured to compare the first version number with the second version number number, to confirm that the first transfer UE information list is an updated transfer UE information list based on the first version number.

With reference to the second aspect, in a possible implementation manner, the receiving unit is further configured to receive a second heartbeat message sent by the first UE; the second heartbeat information includes the device identifier and the third version number of the first UE; the processing unit It is also used to compare the first version number with the third version number, so as to confirm based on the first version number that the first transfer UE information list is an updated transfer UE information list.

With reference to the second aspect, in a possible implementation manner, the processing unit is further configured to change the communication state of the first UE from online to off-line if it does not receive an updated heartbeat message sent by the first UE within a second time. network, or modify the communication status of the first UE as the next-hop UE in the communication path from on-net to off-net.

With reference to the second aspect, in a possible implementation manner, the processing unit is further configured to, before receiving the second heartbeat message, not receive the first transit UE information list, and at a third time after receiving the second heartbeat message, The first transfer UE information list is not received either, and a second request is sent to the first UE, where the second request is used to instruct the first UE to send the first transfer UE information list.

With reference to the second aspect, in a possible implementation manner, the first transit UE information list further includes the communication state of the second UE, the transit hop count of data transmission in the first communication path, and the first UE information in the first communication path UEID of the next-hop UE.

With reference to the second aspect, in a possible implementation manner, the first relay UE information list further includes the networking identifier of the second UE.

With reference to the second aspect, in a possible implementation manner, the first unicast message includes service data, a UEID of a source user equipment, a target UEID, and a transit UEID.

With reference to the second aspect, in a possible implementation manner, the processing unit is further configured to, after receiving the first transfer UE information list sent by the first UE, fail to receive the first transfer UE information list sent by the first UE before a certain time. For the heartbeat message, it may also be considered that the first relay UE information list is the latest, then the first unicast message may be sent based on the first relay UE information list. After a certain period of time, if the first heartbeat message sent by the first UE is still not received, the first unicast message is not sent based on the first relay UE information list.

In the third aspect, the embodiment of the present application provides a chip or a chip system, which is characterized in that it includes a processing circuit and an interface circuit, the interface circuit is used to receive code instructions and transmit them to the processing circuit, and the processing circuit is used to run the code instructions to execute The method described in any possible implementation of any of the above aspects.

In the fourth aspect, the embodiment of the present application provides a computer-readable storage medium, and instructions are stored in the computer-readable storage medium, and when the instructions are run on the communication device, the communication device is made to perform any possible operation of any of the above-mentioned aspects. Implement the method described in How to.

In the fifth aspect, the embodiment of the present application provides a computer program product, which is characterized in that, when the computer program product is executed by the communication device, the communication device is made to perform the method described in any possible implementation of any of the above aspects .

For the beneficial effects of the second aspect to the fifth aspect, please refer to the beneficial effects of the first aspect, which will not be repeated in this embodiment of the present application.

Description of drawings

FIG. 1A-FIG. 1B exemplarily show a schematic diagram of routing establishment provided by an embodiment of the present application;

FIG. 2 exemplarily shows a schematic structural diagram of a communication system 200 provided by an embodiment of the present application;

FIG. 3A exemplarily shows a schematic diagram of a communication topology provided by an embodiment of the present application;

FIG. 3B exemplarily shows a schematic diagram of another communication topology provided by the embodiment of the present application;

FIG. 4 exemplarily shows a schematic structural diagram of a communication system 400 provided by an embodiment of the present application;

FIG. 5 exemplarily shows a flow chart of a method for confirming that the received transfer UE information list is the latest version provided by the embodiment of the present application;

FIG. 6 exemplarily shows a schematic structural diagram of a communication device 600 provided by an embodiment of the present application;

FIG. 7 exemplarily shows a schematic structural diagram of a communication device 700 provided by an embodiment of the present application.

Detailed ways

Embodiments of the present application are described below with reference to the drawings in the embodiments of the present application.

In the following, some terms used in the embodiments of the present application are explained, so as to facilitate the understanding of those skilled in the art.

(1) Candidate user equipment (user equipment, UE) information list

The candidate UE information list records path information of communication paths between one or more other target UEs that can communicate directly or indirectly with the current UE. If the current UE can directly communicate with one or more target UEs, then the transmission data from the current UE to one or more target UEs does not need to be relayed by a relay device. If the current UE cannot directly communicate with one or more target UEs, the transmission data from the current UE to one or more target UEs needs to be relayed by a relay device. There may be one or more communication paths between the current UE and a certain target UE among the one or more target UEs. Wherein, the path information of the communication path may include one or more of the following: device identifier of the target UE, communication status of the target UE, transit hops for data transmission in the communication path, and device identifier of the next-hop UE. Wherein, the communication state of the target UE is on-net or off-net, and the device identifier of the next-hop UE is used to indicate the device identifier of the user equipment adjacent to the current UE in the communication path between the current UE and the target UE.

Exemplarily, the path information of the communication path may be represented as follows (UEO1, on-network, M1 hop, UER1). Wherein, UEO1 represents the device identity of the target UE. On-net means that the communication status of UEO1 is on-net, that is, communication is possible. The M1 hop indicates that data from the current UE arriving at UE01 needs to be transferred by M1 transfer devices. UER1 indicates the device identifier of the user equipment adjacent to the current UE among all the transit devices through which the data from the current UE to UE01 passes. If the current UE can directly communicate with UEO1, then the value of M1 is 0, and UER1 is the same as UEO1. If the current UE cannot directly communicate with UEO1, then the value of M1 is greater than 0, and UER1 is different from UEO1.

(2) Direct communication UE information list

The path information of communication paths between one or more other target UEs that can directly communicate with the current UE is recorded in the direct communication UE information list. That is to say, the current UE can directly communicate with one or more target UEs, so the transmission data from the current UE to one or more target UEs does not need to be relayed by a relay device. Wherein, the path information of the communication path may include one or more of the following: a device identifier of the target UE, and a communication status of the target UE. Wherein, the communication status of the target UE is on-net or off-net. It can be understood that the direct communication UE information list records the path information of the communication path between one or more target UEs that can directly communicate with the current UE, then the transit between the current UE and one or more target UEs The number of hops is 0, and the number of transit hops in the above communication path can be omitted, and the default is 0 hops. And the data between the current UE and one or more other target UEs does not need to be transferred by the relay device, so the device ID of the next-hop UE is the device ID of the target UE, and the device ID of the next-hop UE is in the above communication path The number of transit hops in can be omitted.

Exemplarily, the path information of the communication paths recorded in the direct communication UE information list may be expressed as follows (UE01, online). Wherein, UEO1 represents the device identity of the target UE. On-net means that the communication status of UEO1 is on-net, that is, communication is possible. The number of transit hops in the path information of the communication path recorded in the direct communication UE information list is all 0, and the device identifier of the next-hop UE is the same as the device identifier of the target UE.

(3) Target UE information list

The target UE information list is obtained based on the candidate UE information list. That is to say, each UE screens the path information of the communication path recorded in the locally maintained candidate UE information list through preset rules to obtain part of the path information to obtain the target UE information list. The expression form of the path information of the communication path recorded in the target UE information list is similar to the expression form of the path information of the communication path recorded in the candidate UE information list, which will not be repeated in this embodiment of the present application.

The preset rule may be to find out the path information of one or more communication paths of one or more target UEs in the candidate UE information list, if a certain target UE has path information of multiple communication paths , then retain the path information of x communication paths among the path information of multiple communication paths for a certain target UE, the communication status in the path information of the x communication paths is in the network, and the number of transit hops is less than the preset transit The number of hops, x is greater than or equal to 1. If a certain target UE has only path information of one communication path, the path information of the one communication path is retained.

The preset rule may also be to find out the path information of the communication path of one or more target UEs in the candidate UE information list, and reserve the communication of y target UEs in the path information of the communication path of one or more target UEs The path information of the path, the communication state in the path information of the communication path of y target UEs is the network, and/or the number of transit hops in the path information of the communication path of y target UEs is less than the preset number of transit hops, y greater than or equal to 1.

(4) Transit UE information list

The relay UE information list is for relay user equipment (relay user equipment, Relay UE). Relay UE is a UE capable of relaying information. Based on the target UE information list maintained locally, the Relay UE screens out the path information of the communication paths for which target UEs can provide relay services through preset rules, and obtains the path information of the communication paths of the target UEs that can provide relay services, and The transfer UE information list is obtained based on the path information of the communication path of the target UE that can provide the transfer service. How the Relay UE screens out the path information of the communication path for which target UEs can provide the relay service based on preset rules will be described in detail in subsequent embodiments, and will not be described in this embodiment of the present application.

After the Relay UE obtains the relay UE information list, the Relay UE broadcasts the relay UE information list to other UEs, and other UEs within the communication range with the Relay UE will receive the relay UE information list sent by the Relay UE .

(5) Temporary UE information list

After receiving the relay UE information list sent by the relay UE, the UE will perform the following operations on the relay UE information list to obtain the temporary UE information list. The following operation may be: if the device identifier of the next-hop UE in the path information of a certain communication path in the transit UE information list is the same as the device identifier of the current UE, discard the path information of the certain communication path. If the device identifier of the next-hop UE in the path information of a certain communication path in the transit UE information list is different from the device identifier of the current UE, change the device identifier of the next-hop UE in the path information of the certain communication path to It is the device identifier of the relay UE that sends the relay UE information list, and at the same time, add 1 to the value of the relay hop count in the path information of the certain communication path.

Currently, there are three ways to implement communication between devices.

Method 1: UE discovery and identification in the long term evolution (LTE) D2D communication protocol formulated by the 3rd generation partnership project (3GPP) standards organization is implemented through the D2D discovery process. Specifically, each UE continuously sends a discovery message, and the discovery message is used for other UEs within the communication distance to discover that the UE is in the network state. After other UEs receive the discovery message of the UE, other UEs can send and receive messages with the UE.

However, method 1 can only realize data transmission between two UEs that communicate directly, and cannot realize data transmission between two UEs that cannot communicate directly through a transfer method.

Method 2: Each UE is preset with device identifiers (such as mac addresses, etc.) of other UEs that can communicate. The UE may find the device identity of the UE that wants to communicate with the device identity of other UEs stored locally, and then perform communication based on the device identity of the UE.

However, in method 2, the communication is realized by presetting the device ID of the UE. If the communication status of the preset UE changes in real time, or the preset UE moves in real time and exceeds the communication distance of the current UE, the current UE cannot communicate with the preset UE. The configured UE communicates. Or other UEs are newly added around the current UE, and the device identifier of the newly added UE is not preset in the current UE, then the current UE cannot communicate with the newly added UE. That is to say, in the second manner, the communication state of the communicating UE and the path information of the communication path with the communicating UE cannot be determined in real time.

Method 3: AD hoc on-demand distance vector routing protocol (AD hoc on-demand distance vector, AODV) or multicast wireless ad hoc network on-demand plane distance vector routing protocol (multicast AD hoc hn-demand distance vector) is Currently commonly used wireless multi-hop AD hoc network routing protocol. The following uses AODV as an example to introduce the route discovery process. When the source node needs to transmit data to the destination node, a route from the source node to the destination node needs to be established. Specifically, the source node will broadcast a route request packet (route request packet, RREQ), which carries the address of the source node and the address of the destination node in the RREQ, and RREQ is used to find the route from the source node to the destination node. When the destination node receives the RREP, the destination node will reply a Route Reply Packet (RREP) to the source node in unicast mode, and when the source node receives the route reply message RREP sent by the destination node, the Routing between nodes is established.

1A-1B exemplarily show the process of establishing a route from a source node to a destination node.

Exemplarily, the source node is node A, and the destination node is node E.

In Figure 1A, when node A needs to communicate with node E, when node A sends RREQ in a broadcast manner, other nodes within the communication range with node A can receive the RREQ sent by node A, such as node B and Node F receives the RREQ sent by node A, the source address carried in the RREQ is the address of node A, and the destination address is the address of node E. After Node B and Node F receive the RREQ sent by Node A, they resolve the destination address carried by the RREQ. If the destination address is different from the address of Node B and the address of Node F, then Node B and Node F broadcast the RREQ as sent to other nodes. Node B will generate a routing table, the source node in the routing table is node A, the destination node is node E, and the next hop node is node A. Node F will generate a routing table, the source node in the routing table is node A, the destination node is node E, and the next hop node is node A. Node C will receive the RREQ sent by node B, node G will receive the RREQ sent by node F, node C will receive the RREQ sent by node B and node G will parse out the destination address carried by the RREQ after receiving the RREQ sent by node FB , if the destination address is different from the address of node C and the address of node G, then node C and node G send the RREQ to other nodes in the form of broadcast. Node C will generate a routing table, the source node in the routing table is node A, the destination node is node E, and the next hop node is node B. Node G will generate a routing table, the source node in the routing table is node A, the destination node is node E, and the next hop node is node F. Node D will receive the RREQ sent by node C. After receiving the RREQ sent by node C, node D will parse out the destination address carried by the RREQ. If the destination address is different from the address of node D, then node D will broadcast the RREQ as Forms are sent to other nodes. Node D will generate a routing table. In the routing table, the source node is node A, the destination node is node E, and the next hop node is node C. Node E will receive the RREQ sent by node D. After receiving the RREQ sent by node D, node E will analyze the destination address carried by RREQ. Node E will generate a routing table. The source node in the routing table is node A, and the destination node is node E, and the next hop node is node D. If the destination address is the same as that of node E, node E discards the received RREQ, and then node E searches for a route to source node A. Specifically, node E generates a RREP, and sends the RREP to node A in unicast form based on a route created by node A according to a route created by the RREQ sent by node A.

As shown in Figure 2, node E sends the RREP to the next hop node (i.e. node D). After node D receives the RREP, node E will generate a routing table. The source node in the routing table is node E, and the destination node is Node A, the next hop node is node E. If the destination address is different from the address of node D, then node D sends the RREP to the next hop node (ie, node C) in unicast form. After node C receives the RREP, node C will generate a routing table. In the routing table, the source node is node E, the destination node is node A, and the next hop node is node D. If the destination address is different from the address of node C, then node C sends the RREP to the next hop node (ie, node B) in unicast form. After node B receives the RREP, node B will generate a routing table, the source node in the routing table is node E, the destination node is node A, and the next hop node is node C. If the destination address is different from the address of node B, then node B sends the RREP to the next hop node (ie, node A) in unicast form. After node A receives the RREP, node A will generate a routing table, the source node in the routing table is node E, the destination node is node A, and the next hop node is node B. If the destination address is the same as the address of node A, then node A determines that node E can communicate, and the routes between node A to node F and node F to node A have been established, and node A and node E can establish Routers send and receive messages to each other.

However, in the third method, and before each communication, the source node needs to establish a route with the destination node through the methods shown in Figure 1A and Figure 1B, in order to ensure the reliability of communication, that is to say, the route is when communication is required It will be established only when the communication delay is affected. And in the third way, the source node cannot know the communication status of the destination node in advance, so the route between the source node and the destination node may also fail to be established, resulting in the problem that the source node and the destination node cannot communicate.

Based on the above analysis, an embodiment of the present application provides a D2D communication method, the method includes: the UE in the D2D network receives the first relay UE information list sent by the Relay UE. Wherein, the first relay UE information list includes path information of the first communication path between the Relay UE and the target UE. In a possible implementation manner, the UE receives heartbeat information sent by the relay UE, and determines whether the first relay UE information list is an updated relay UE information list based on the heartbeat information. The heartbeat information includes the device identification and version number of the Relay UE, and the version number is used to confirm whether the first relay UE information list is an updated relay UE information list; when it is confirmed based on the first version number that the first relay UE information list is an updated relay UE When the information list is used, the first unicast information is sent based on the first relay UE information list. It should be noted that the Relay UE sends heartbeat information continuously (for example, 5s is a cycle).

In another possible implementation, after the UE in the D2D network receives the first relay UE information list sent by the Relay UE, it can also be considered that the first relay UE does not receive the heartbeat message sent by the Relay UE before a certain period of time. If the relay UE information list is the latest, then the first unicast message may be sent based on the first relay UE information list. After a certain period of time, the heartbeat information sent by the relay UE is still not received, and the first unicast message is no longer sent based on the first relay UE information list.

Through the above method, the UE can confirm whether it is the latest relay UE information list information based on the version number contained in the received heartbeat information. When it is confirmed that it is not the latest relay UE information list information, the UE sends a message to the relay UE Requesting to acquire the latest transfer UE information list improves the reliability of the communication state and communication path of the target UE maintained by the UE.

A communication method provided by the embodiment of the present application will be described in detail below in combination with the first embodiment and the second embodiment.

Embodiment one

The scenario involved in the first embodiment is a scenario in which two or more Relay UEs are included in the D2D network.

In Embodiment 1, the UE receives heartbeat information continuously sent by other UEs to generate a direct communication UE information list. For the Relay UE, the Relay UE will generate a relay UE information list based on the direct communication UE information list, and the Relay UE will broadcast the relay UE information list and the device identifier of the Relay UE to other UEs. After receiving the relay UE information list of the relay UE, other UEs combine the relay UE information list with the locally maintained direct communication UE information list to obtain the first candidate UE information list. If the direct communication UE information list or the transit UE information list changes, the path information recorded in the communication path in the first candidate UE information list will also change. In this way, each UE can know the communication state of the target UE and the path information of the communication path to the target UE in real time by maintaining a first candidate UE information list.

Please refer to FIG. 2 . FIG. 2 is a schematic structural diagram of a communication system 200 provided by an embodiment of the present invention. The communication system 200 may include user equipment 100 , user equipment 200 , user equipment 300 , user equipment 400 and user equipment 500 . Wherein, the user equipment 100 and the user equipment 500 are non-relay UEs, that is to say, the user equipment 100 and the user equipment 500 cannot forward data. For example, in the case that the user equipment 100 can communicate with the user equipment 400, the user equipment 100 can receive the data sent by the user equipment 200, but the user equipment 100 cannot forward the received data sent by the user equipment 200 to the user equipment 400 or User equipment 300. The user equipment 200, the user equipment 300, and the user equipment 400 are Relay UEs, that is, the user equipment 200, the user equipment 300, and the user equipment 400 can forward data. For example, the user equipment 200 may receive the data sent by the user equipment 100 and forward the data sent by the user equipment 100 to the user equipment 400 or the user equipment 300 . It should be understood that the communication system 200 to which the method of the embodiment of the present application can be applied may include more or fewer user equipments.

Based on the schematic structural diagram of a communication system 200 provided in FIG. 2 , how each UE maintains a candidate UE information list in a scenario where there are two or more Relay UEs in a D2D network will be described below.

First, each UE continuously sends heartbeat information, and the heartbeat information carries the device identifier of each UE. Each UE sends heartbeat information in the form of broadcast, and UEs within a communication distance can receive heartbeat information sent by other UEs. Each UE receives heartbeat messages sent by other UEs to generate a direct communication UE information list.

The direct communication UE information list includes the equipment identification of the target UE, the communication status of the target UE, the number of transit hops and the equipment identification (user equipment identification, UEID) of the next-hop user equipment, the communication status of the target UE is on-net or off-net, The next-hop UEID is used to indicate the device identity of the user equipment adjacent to the current UE in the communication path between the current UE and the target UE. For example, the user equipment 100 receives the heartbeat information sent by the user equipment 200 to generate the direct communication UE information list of the user equipment 100 . The user equipment 200 receives the heartbeat information sent by the user equipment 100 , the user equipment 300 and the user equipment 400 to generate a direct communication UE information list of the user equipment 200 . The user equipment 300 receives the heartbeat information sent by the user equipment 200 , the user equipment 400 and the user equipment 500 to generate a direct communication UE information list of the user equipment 300 . The user equipment 400 receives the heartbeat information sent by the user equipment 200 and the user equipment 300 to generate a direct communication UE information list of the user equipment 400 . The user equipment 500 receives the heartbeat information sent by the user equipment 300 to generate a direct communication UE information list of the user equipment 500 .

Table 1

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200

Table 1 exemplarily shows the direct communication UE information list of the user equipment 100 . Table 1 can be expressed as (user equipment 200, online, 0, user equipment 200). The device identifier of the target UE shown in Table 1 is user equipment 200, the communication status of user equipment 200 is on the network, the number of transit hops for the data sent by user equipment 100 to reach user equipment 200 is 0 hops, and the data sent by user equipment 100 arrives at The UEID of the next hop of the user equipment 200 is the user equipment 200 .

Optionally, since the transit hop count in the direct communication UE information list is 0, and the next-hop UEID is the same as the device identifier of the target UE, the transit hop count and the next-hop UEID in the direct communication UE information list can be omitted, In this way, the consumption of the direct communication UE information list maintained by each UE can be saved.

Then the direct communication UE information list shown in Table 1 can be simplified into the format of Table 2.

Table 2

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE
用户设备200user equipment 200	在网online

Table 2 exemplarily shows the simplified direct communication UE information list of the user equipment 100 . Table 2 may be expressed as (user equipment 200, on-net). It should be noted that the direct communication UE information list described in the following embodiments of the present application is a simplified direct communication UE information list.

Similarly, the direct communication UE information lists of the user equipment 200, the user equipment 300, the user equipment 400, and the user equipment 500 are shown in sequence below.

table 3

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE
用户设备100user equipment 100	在网online
用户设备300user equipment 300	在网online
用户设备400user equipment 400	在网online

Table 3 exemplarily shows the direct communication UE information list of the user equipment 200 . Table 3 may be expressed as (user equipment 100, online), (user equipment 300, online), (user equipment 400, online).

Table 4

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE
用户设备200user equipment 200	在网online
用户设备400user equipment 400	在网online
用户设备500user equipment 500	在网online

Table 4 exemplarily shows the direct communication UE information list of the user equipment 300 . Table 4 may be expressed as (user equipment 200, online), (user equipment 400, online), (user equipment 500, online).

table 5

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE
用户设备200user equipment 200	在网online
用户设备300user equipment 300	在网online

Table 5 exemplarily shows the direct communication UE information list of the user equipment 400 . Table 5 may be expressed as (user equipment 200, online), (user equipment 300, online).

Table 6

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE
用户设备300user equipment 300	在网online

Table 6 exemplarily shows the direct communication UE information list of the user equipment 500 . Table 6 may be expressed as (user equipment 300, on-net).

For the Relay UE in the D2D network, based on the obtained direct communication UE information list, the Relay UE will filter out the target UEs willing to forward data for which target UEs based on the preset rule 1, and obtain the relay UE information list.

Preset rule 1 can be any one or more of the following:

Way 1: In order to reduce the network scale and the load of sending data, the types of target UEs in the transfer UE information list are less than the preset number.

For example, if there are 5 types of target UEs in the direct communication UE information list of the Relay UE, but the preset target UE types in the relay UE information list do not exceed 4, then the Relay UE needs to be selected from the 5 target UEs The path information of the communication path of no more than 4 target UEs is saved in the transit UE information list.

Method 2: The priority of the target UE in the transit UE information list is as follows: the priority of the target UE on the network is higher than that of the target UE off the network, and the priority of the target UE with a small hop number is higher than that of a large hop number.

For example, the relay UE may select from the direct communication UE information list the path information of the communication path of the target UE whose communication status is on the network and save it in the relay UE information list. Alternatively, a certain relay UE may select from the direct communication UE information list the path information of the communication path of the target UE whose transit times are less than the preset hop count and save it in the transit UE information list.

Mode 3: Relay UE receives user operation and selects path information of one or more target UEs from the direct communication UE information list and saves them in the relay UE information list.

Method 4: The Relay UE screens out the path information of one or more target UEs whose transit hops are less than the preset hops from the direct communication UE information list and saves them in the transit UE information list.

It should be noted that the manners of obtaining the transfer UE information list based on the direct communication UE information list are not limited to the above four methods, and may also be other manners, which are not limited in this embodiment of the present application.

Secondly, after the Relay UE in the D2D network obtains the relay UE information list, the Relay UE broadcasts the locally obtained relay UE information list and the device identifier of the Relay UE to other UEs (including ordinary UEs and Relay UEs) . Other UEs within the communication distance with the Relay UE will receive the relay UE information list and the device identification of the Relay UE sent by the Relay UE.

Optionally, the Relay UE may periodically broadcast the locally obtained relay UE information list and the device identifier of the Relay UE to other UEs.

Optionally, after the Relay UE detects that the local relay UE information list has changed, it sends the updated complete relay UE information list and the device identifier of the Relay UE to other UEs by broadcast.

Optionally, after the Relay UE detects a change in the local relay UE information list, it only broadcasts the path information of the changed target UE and the device identifier of the Relay UE to other UEs.

Optionally, before the Relay UE sends the relay UE information list to other UEs, it can delete the next-hop UEID in each communication path in the relay UE information list, and then delete the relay UE information after deleting the next-hop UEID The list is sent to other UEs. In this way, after other UEs receive the relay UE information list after deleting the next-hop UEID, they will add the next-hop UEID to the relay UE information list after deleting the next-hop UEID as the relay UE that sent the relay UE information list Equipment Identity. In this way, the network load for the Relay UE to send the relay UE information list can be reduced.

Optionally, before the Relay UE sends the relay UE information list to other UEs, it first adds 1 to the relay hop count in the relay UE information list, and then sends the relay UE information list after the relay hop count plus 1 to other UEs. In this way, after receiving the transfer UE information list, other UEs do not need to add 1 to the transfer hop count in the transfer UE information list, which can reduce the processing load of other UEs.

In the following embodiments of the present application, the Relay UE does not perform any processing and sends the relay UE information list to other UEs as an example for illustration.

Exemplarily, it is assumed that the relay UE information list obtained by each relay UE in the communication system 200 is the same as the direct communication UE information list, that is, the communication paths in the direct communication UE information list are not deleted. Afterwards, each Relay UE in the communication system 200 sends the relay UE information list to other UEs by broadcasting.

For example, the user equipment 200 sends the transfer UE information list 1 of the user equipment 200 and the device identifier of the user equipment 200 to the user equipment 100, the user equipment 300 and the user equipment 400 respectively, and the path information in the transfer UE information list 1 of the user equipment 200 It is the same as the path information in the direct communication UE information list of the user equipment 200 . The user equipment 300 sends the transfer UE information list 1 of the user equipment 300 and the device identifier of the user equipment 300 to the user equipment 200, the user equipment 400, and the user equipment 500 respectively, and the path information in the transfer UE information list 1 of the user equipment 300 and the user equipment The path information in the direct communication UE information list of device 300 is the same. The user equipment 400 sends the transfer UE information list 1 of the user equipment 400 and the device identifier of the user equipment 400 to the user equipment 200 and the user equipment 300 respectively, and the path information in the transfer UE information list 1 of the user equipment 400 and the direct link of the user equipment 400 The path information in the communication UE information list is the same.

After receiving the relay UE information list sent by the relay UE, other UEs combine the locally maintained direct communication UE information list and the relay UE information list to obtain a candidate UE information list.

Before the UE combines the locally maintained direct communication UE information list and the transfer UE information list, it needs to process the received transfer UE information list to obtain a temporary UE information list.

The UE may process the received transfer UE information list based on preset rule 2 to obtain a temporary UE information list.

The preset rule 2 can be any one or several of the following methods:

Method 1: Among the communication paths recorded in the received transit UE information list, delete the communication paths in which the device identifier of the target UE recorded in the path information of the route path is the same as its own device identifier, and obtain the temporary UE information list.

Method 2: Among the communication paths recorded in the received transit UE information list, delete the communication paths whose next-hop UEID recorded in the path information of the path path is the same as its own device identifier, and obtain the temporary UE information list.

Method 3: In the communication path recorded in the received transit UE information list, increase the transit hop count in the communication path in which the UEID of the next hop recorded in the path information of the path path is different from its own device identifier by 1, and at the same time add The next-hop UEID in the path information of the corresponding communication path is modified to the device identifier sent by the Relay UE that sent the relay UE information list, and the temporary UE information list is obtained.

It should be noted that the manners of obtaining the temporary UE information list based on the transit UE information list are not limited to the above two manners, and may also be other manners, which are not limited in this embodiment of the present application.

The following describes how the user equipment 200 obtains the temporary UE information list according to the received relay UE information list.

The user equipment 200 can directly communicate with the user equipment 300 and the user equipment 400, then the user equipment 200 can receive the transfer UE information lists sent by the user equipment 300 and the user equipment 400 respectively.

First, the user equipment 200 receives the relay UE information list sent by the user equipment 300. From the foregoing, it can be seen that the relay UE information list of the user equipment 300 and the direct communication UE information list of the user equipment 300 are the same.

The user equipment 200 processes the transit UE information list of the user equipment 300 based on the above preset rule 2 to obtain the temporary UE information list 1 of the user equipment 200 .

Table 7

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备400user equipment 400	在网online	11	用户设备300user equipment 300
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300

Table 7 shows the first temporary UE information list obtained by the user equipment 200 based on the transfer UE information list of the user equipment 300 . In Table 7, the device identifier of the target UE is user equipment 400, the communication status of user equipment 400 is online, the number of transit hops passed by the data from user equipment 200 to user equipment 400 is 1, and the data from user equipment 200 to user equipment 400 The UEID of the next hop is the user equipment 300 . The device identifier of the target UE may also be the user equipment 500, the communication status of the user equipment 500 is online, the number of transit hops passed by the data from the user equipment 200 to the user equipment 500 is 1, and the next step of the data from the user equipment 200 to the user equipment 500 is 1. The one-hop UEID is the user equipment 300 .

The user equipment 200 will also receive the relay UE information list sent by the user equipment 400. As can be seen from the foregoing, the relay UE information list of the user equipment 400 is the same as the direct communication UE information list of the user equipment 400.

The transit UE information list of the user equipment 400 is processed based on the above preset rule 2 to obtain the temporary UE information list 2 of the user equipment 200 .

Table 8

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备300user equipment 300	在网online	11	用户设备400user equipment 400

Table 8 shows the second temporary UE information list obtained by the user equipment 200 based on the transfer UE information list of the user equipment 400 . In Table 8, the device identifier of the target UE is user equipment 300, the communication status of user equipment 300 is online, the number of transit hops passed by the data from user equipment 200 to user equipment 300 is 1, and the data from user equipment 200 to user equipment 300 The UEID of the next hop is the user equipment 400.

By analogy, the user equipment 100 may also receive the transfer UE information list sent by the user equipment 200 . And based on the above preset rule 2, the transit UE information list of the user equipment 200 is processed, and the temporary UE information list 1 of the user equipment 100 shown in Table 9 is obtained.

Table 9

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备300user equipment 300	在网online	11	用户设备200user equipment 200
用户设备400user equipment 400	在网online	11	用户设备200user equipment 200

The user equipment 300 may also receive the transfer UE information lists sent by the user equipment 200 and the user equipment 400 respectively.

The user equipment 300 processes the transit UE information list of the user equipment 200 based on the above preset rule 2, and obtains the temporary UE information list 1 of the user equipment 300 shown in Table 10.

Table 10

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200
用户设备400user equipment 400	在网online	11	用户设备200user equipment 200

The user equipment 300 processes the transit UE information list of the user equipment 400 based on the above preset rule 2, and obtains the temporary UE information list 2 of the user equipment 300 shown in Table 11.

Table 11

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	11	用户设备400user equipment 400

The user equipment 400 may also receive the transfer UE information lists sent by the user equipment 200 and the user equipment 300 respectively.

The user equipment 400 processes the transit UE information list of the user equipment 200 based on the above preset rule 2, and obtains the temporary UE information list 1 of the user equipment 400 shown in Table 12.

Table 12

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200
用户设备300user equipment 300	在网online	11	用户设备200user equipment 200

The user equipment 400 processes the transit UE information list of the user equipment 300 based on the above preset rule 2, and obtains the temporary UE information list 2 of the user equipment 400 shown in Table 13.

Table 13

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	11	用户设备300user equipment 300
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300

The user equipment 500 may also receive the transfer UE information list sent by the user equipment 300 . And based on the above preset rule 2, the transit UE information list of the user equipment 300 is processed, and the temporary UE information list 1 of the user equipment 500 shown in Table 14 is obtained.

Table 14

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	11	用户设备300user equipment 300
用户设备400user equipment 400	在网online	11	用户设备300user equipment 300

After obtaining the temporary UE information list, other UEs combine the temporary UE information list with the locally maintained direct communication UE information list to obtain a candidate UE information list.

The UE may combine the temporary UE information list and the direct communication UE information list based on preset rule 3 to obtain a candidate UE information list.

The default rule three can be any one or several of the following:

Method 1: If the device ID and next-hop UEID of the target UE in a communication path in the temporary UE information list are the same as the device ID and next-hop UEID of the target UE in a communication path in the direct communication UE information list If they are the same, the communication path in the direct communication UE information list is deleted. That is, new information overwrites old information.

Method 2: If the relay UE information list sent by the Relay UE is a complete relay UE information list, it includes the path information of all target UEs, not just the changed path information of the target UE sent. Then if the communication path of a certain target UE does not exist in the temporary UE information list, but the communication path of the certain target UE exists in the direct communication UE information list, and the communication path of the certain target UE in the direct communication UE information list If the UEID of the next hop in the communication path is the same as the device identifier of the Relay UE that sends the relay UE information list, and the number of relay hops in the communication path is greater than 0, it means that the Relay UE will not provide the function of forwarding data to a certain target UE. Then, the UE changes the communication state of the communication path of the certain target UE in the direct communication UE information list from on-net to off-net.

Method 3: For the temporary UE information list and the direct communication UE information list, if the UE storage space only allows saving X pieces of path information for the same target UE, then set the communication status in the path information of the communication path of the same target UE to " The communication paths of "on-net" are sorted according to the number of transit hops from small to large, and X communication paths with a number of hops less than the preset number are selected and reserved. If the number of transit hops in multiple communication paths of the same target UE is the same, reserve the one with the highest received power among the multiple communication paths of the same target UE, or preferentially select the transmission UE with higher received power (or) to obtain target UE information.

Among the communication paths, the communication path whose communication state is "off-grid" has the lowest priority, and the UE may delete the communication path whose communication state is "off-grid" among the communication paths of the target UE.

Method 4: For the temporary UE information list and the direct communication UE information list, if the storage space of the device only allows Y different types of target UEs to be stored, the "on-network" target UE has a higher priority than the "off-network" target UE. A target UE with a small hop count has a higher priority than a target UE with a large hop count. Or the user chooses which communication paths of the target UEs to save.

Way 5: In order to reduce the network scale, delete the path information of the communication paths whose transit hop count is greater than the preset hop count in the transfer UE information list and the direct communication information list.

It should be noted that combining the temporary UE information list and the direct communication UE information list to obtain the candidate UE information list is not limited to the above five types, and other methods are also possible, which are not limited in this embodiment of the present application.

The following describes how the user equipment 200 combines the temporary UE information list 1, the temporary UE information list 2 and the direct communication UE information list of the user equipment 200.

The user equipment 200 merges the temporary UE information list 1, the temporary UE information list 2 and the direct communication UE information list of the user equipment 200 based on the above preset rule 3 to obtain the candidate UE information list 1 of the user equipment 200 .

Table 15

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备100user equipment 100	在网online	00	用户设备100user equipment 100
用户设备300user equipment 300	在网online	00	用户设备300user equipment 300
用户设备400user equipment 400	在网online	00	用户设备400user equipment 400
用户设备400user equipment 400	在网online	11	用户设备300user equipment 300
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300
用户设备300user equipment 300	在网online	11	用户设备400user equipment 400

Table 15 shows that the user equipment 200 obtains the first candidate UE information list of the user equipment 200 based on the first temporary UE information list, the second temporary UE information list and the direct communication UE information list of the user equipment 200 . In Table 7, the device identifier of the target UE is user equipment 100, the communication status of user equipment 100 is online, the number of transit hops for the data of user equipment 200 to reach user equipment 100 is 0, and the number of transit hops for data of user equipment 200 to reach user equipment 100 is 0. The next hop UEID is the user equipment 100 . The device identifier of the target UE may also be the user equipment 300, the communication status of the user equipment 300 is online, the number of transit hops for the data of the user equipment 200 to reach the user equipment 300 is 0, and the data of the user equipment 200 arrives at the next hop of the user equipment 300. The jump UEID is the user equipment 300 . The device identifier of the target UE can also be the user equipment 400, the communication status of the user equipment 400 is on the network, the number of transit hops for the data of the user equipment 200 to reach the user equipment 400 is 0, and the next hop for the data of the user equipment 200 to reach the user equipment 400 UEID is user equipment 400 . The device identifier of the target UE can also be the user equipment 400, the communication status of the user equipment 400 is on the network, the number of transit hops for the data of the user equipment 200 to reach the user equipment 400 is 1, and the next hop for the data of the user equipment 200 to reach the user equipment 400 UEID is user equipment 300 . The device identifier of the target UE can also be the user equipment 500, the communication status of the user equipment 500 is on the network, the number of transit hops for the data of the user equipment 200 to reach the user equipment 500 is 1, and the next hop for the data of the user equipment 200 to reach the user equipment 500 UEID is user equipment 300 . The device identifier of the target UE can also be the user equipment 300, the communication status of the user equipment 300 is on the network, the number of transit hops for the data of the user equipment 200 to reach the user equipment 300 is 1, and the next hop for the data of the user equipment 200 to reach the user equipment 300 UEID is user equipment 400 .

By analogy, the user equipment 100 may combine the temporary UE information list 1 of the user equipment 100 and the direct communication UE information list of the user equipment 100 to obtain the candidate UE information list 1 of the user equipment 100 .

Table 16

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200
用户设备300user equipment 300	在网online	11	用户设备200user equipment 200
用户设备400user equipment 400	在网online	11	用户设备200user equipment 200

Table 16 shows that the user equipment 100 obtains the candidate UE information list 1 of the user equipment 100 based on the temporary UE information list 1 of the user equipment 100 and the direct communication UE information list of the user equipment 100 .

The user equipment 300 may combine the temporary UE information list 1 of the user equipment 300 , the temporary UE information list 2 and the direct communication UE information list of the user equipment 300 to obtain the candidate UE information list 1 of the user equipment 300 .

Table 17

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200
用户设备400user equipment 400	在网online	00	用户设备400user equipment 400
用户设备500user equipment 500	在网online	00	用户设备500user equipment 500
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200
用户设备400user equipment 400	在网online	11	用户设备200user equipment 200
用户设备200user equipment 200	在网online	11	用户设备400user equipment 400

Table 17 shows that the user equipment 300 obtains the first candidate UE information list of the user equipment 300 based on the first temporary UE information list of the user equipment 300 , the second temporary UE information list and the direct communication UE information list of the user equipment 300 .

The user equipment 400 may combine the first temporary UE information list of the user equipment 400 , the second temporary UE information list and the direct communication UE information list of the user equipment 400 to obtain the first candidate UE information list of the user equipment 400 .

Table 18

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200
用户设备300user equipment 300	在网online	00	用户设备300user equipment 300
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200
用户设备300user equipment 300	在网online	11	用户设备200user equipment 200
用户设备200user equipment 200	在网online	11	用户设备300user equipment 300
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300

Table 18 shows that the user equipment 400 obtains the candidate UE information list 1 of the user equipment 400 based on the temporary UE information list 1 of the user equipment 400 , the temporary UE information list 2 and the direct communication UE information list of the user equipment 400 .

The user equipment 500 may combine the temporary UE information list 1 of the user equipment 500 and the direct communication UE information list of the user equipment 500 to obtain the candidate UE information list 1 of the user equipment 500 .

Table 19

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备300user equipment 300	在网online	00	用户设备300user equipment 300
用户设备200user equipment 200	在网online	11	用户设备300user equipment 300
用户设备400user equipment 400	在网online	11	用户设备300user equipment 300

Table 19 shows that the user equipment 500 obtains the candidate UE information list 1 of the user equipment 500 based on the temporary UE information list 1 of the user equipment 500 and the direct communication UE information list of the user equipment 500 .

After the UE obtains the candidate UE information list, the candidate UE information list may record two or more different paths of the same UE, then the UE can communicate from two or more different communication paths of the same target UE. An optimal communication path is screened out, and a target UE information list is generated. In this way, what the UE maintains is the optimal path to each target UE. Here, the optimal path means that the communication state of the target UE in the communication path is on the network, and the number of transit hops is the least.

Exemplarily, the user equipment 100 will filter out the optimal communication path of the same target UE based on the candidate UE information list 1 of the user equipment 100, and obtain the target UE information list of the user equipment 100 as shown in Table 20.

Table 20

Based on the candidate UE information list 1 of the user equipment 200, the user equipment 200 screens out the optimal communication path of the same target UE, and obtains the target UE information list of the user equipment 200 as shown in Table 21.

Table 21

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备100user equipment 100	在网online	00	用户设备100user equipment 100
用户设备300user equipment 300	在网online	00	用户设备300user equipment 300
用户设备400user equipment 400	在网online	00	用户设备400user equipment 400
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300

Based on the candidate UE information list 1 of the user equipment 300, the user equipment 300 screens out the optimal communication path of the same target UE, and obtains the target UE information list of the user equipment 300 as shown in Table 22.

Table 22

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200
用户设备400user equipment 400	在网online	00	用户设备400user equipment 400
用户设备500user equipment 500	在网online	00	用户设备500user equipment 500
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200

Based on the candidate UE information list 1 of the user equipment 400, the user equipment 400 screens out the optimal communication path of the same target UE, and obtains the target UE information list of the user equipment 400 as shown in Table 23.

Table 23

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200
用户设备300user equipment 300	在网online	00	用户设备300user equipment 300
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300

Based on the candidate UE information list 1 of the user equipment 500, the user equipment 500 screens out the optimal communication path of the same target UE, and obtains the target UE information list of the user equipment 500 as shown in Table 24.

Table 24

After each UE obtains the maintained target UE information list, the Relay UE will periodically obtain the relay UE information list based on the target UE information list through the preset rule 1 introduced above. In this way, the relay UE can periodically send the relay UE information list to other UEs based on the relay UE information list maintained in real time, so that other UEs can update the locally maintained candidate UE information list. Or, based on the relay UE information list maintained in real time, the Relay UE can monitor whether the relay UE information list has changed, and after the relay UE information list changes, it will relay the changed path information in the relay UE information list or complete The transfer UE information list is sent to other UEs, so that other UEs can update the locally maintained candidate UE information list.

Here, the Relay UE obtains the relay UE information list based on the target UE information list through the preset rule 1 introduced above. The transfer UE information list is obtained from the target UE information list, and the transfer UE information list is obtained based on the direct communication UE information list. In this embodiment of the present application, the method of how the Relay UE obtains the relay UE information list based on the target UE information list through the above-mentioned preset rule 1 will not be described in detail.

Exemplarily, the user equipment 200 processes the target information list based on a preset rule, and obtains the second transfer UE information list of the user equipment 200 as shown in Table 25.

Table 25

Exemplarily, the user equipment 300 processes the target information list based on a preset rule, and obtains the second transfer UE information list of the user equipment 300 as shown in Table 26.

Table 26

Exemplarily, the user equipment 400 processes the target information list based on a preset rule, and obtains the second transfer UE information list of the user equipment 400 as shown in Table 27.

Table 27

After the Relay UE obtains the relay UE information list based on the target UE information list, the Relay UE broadcasts the updated relay UE information list and the device identifier of the Relay UE to other UEs, and other UEs receive the information sent by the Relay UE. After the updated transfer UE information list, other UEs combine the locally maintained candidate UE information list with the received updated transfer UE information list to obtain an updated candidate UE information list.

Before combining the locally maintained candidate UE information list with the received updated transit UE information list, the UE needs to process the received updated transit UE information list to obtain an updated temporary UE information list. Specifically, the UE may process the received updated transit UE information list based on the preset rule 2 introduced in the above embodiment, to obtain an updated temporary UE information list. The embodiments of this application will not be described in detail.

Specifically, the user equipment 100 may receive the transfer UE information list 2 sent by the user equipment 200, and process the transfer UE information list 2 of the user equipment 200 based on the above preset rule 2, and obtain the user equipment 100 as shown in Table 28 Temporary UE information list 2.

Table 28

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备300user equipment 300	在网online	11	用户设备200user equipment 200
用户设备400user equipment 400	在网online	11	用户设备200user equipment 200
用户设备500user equipment 500	在网online	22	用户设备200user equipment 200

The user equipment 200 may receive the transfer UE information list 2 sent by the user equipment 300, and process the transfer UE information list 2 of the user equipment 300 based on the above preset rule 2 to obtain the temporary UE information of the user equipment 200 as shown in Table 29. Information list three.

Table 29

The user equipment 200 may receive the transfer UE information list 2 sent by the user equipment 400, and process the transfer UE information list 2 of the user equipment 400 based on the above preset rule 2 to obtain the temporary UE information of the user equipment 200 as shown in Table 30. Information list four.

Table 30

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备300user equipment 300	在网online	11	用户设备400user equipment 400
用户设备500user equipment 500	在网online	22	用户设备400user equipment 400

The user equipment 300 may receive the transfer UE information list 2 sent by the user equipment 200, and process the transfer UE information list 2 of the user equipment 200 based on the above preset rule 2, and obtain the temporary UE information of the user equipment 300 as shown in Table 31. Information list three.

Table 31

The user equipment 300 may receive the transfer UE information list 2 sent by the user equipment 400, and process the transfer UE information list 2 of the user equipment 400 based on the above preset rule 2 to obtain the temporary UE information of the user equipment 300 as shown in Table 32. Information list four.

Table 32

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	11	用户设备400user equipment 400
用户设备100user equipment 100	在网online	22	用户设备400user equipment 400

The user equipment 400 may receive the transfer UE information list 2 sent by the user equipment 200, and process the transfer UE information list 2 of the user equipment 200 based on the above preset rule 2 to obtain the temporary UE information of the user equipment 400 as shown in Table 33. Information list three.

Table 33

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200
用户设备300user equipment 300	在网online	11	用户设备200user equipment 200
用户设备500user equipment 500	在网online	22	用户设备200user equipment 200

The user equipment 400 may receive the transfer UE information list 2 sent by the user equipment 300, and process the transfer UE information list 2 of the user equipment 300 based on the above preset rule 2 to obtain the temporary UE information of the user equipment 400 as shown in Table 34. Information list four.

Table 34

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	11	用户设备300user equipment 300
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300
用户设备100user equipment 100	在网online	22	用户设备300user equipment 300

The user equipment 500 may receive the transfer UE information list 2 sent by the user equipment 300, and process the transfer UE information list 2 of the user equipment 300 based on the above preset rule 2, and obtain the temporary UE information of the user equipment 500 as shown in Table 35. Information list two.

Table 35

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	11	用户设备300user equipment 300
用户设备400user equipment 400	在网online	11	用户设备300user equipment 300
用户设备100user equipment 100	在网online	22	用户设备300user equipment 300

After obtaining the updated temporary UE information list, other UEs combine the updated temporary UE information list with the locally maintained candidate UE information list to obtain an updated candidate UE information list.

The UE may combine the updated temporary UE information list with the locally maintained candidate UE information list based on preset rule 3 to obtain an updated candidate UE information list. For details, reference may be made to relevant descriptions in the aforementioned preset rule 3, which will not be repeated in this embodiment of the present application.

Here, based on the updated temporary UE information list and the locally maintained candidate UE information list, the UE obtains the updated candidate UE information list based on the preset rule three introduced above, which is directly combined with the UE based on the temporary UE information list and the locally maintained list. The principle of merging the communication UE information list to obtain the candidate UE information list is the same, but here is based on the combination of the updated temporary UE information list and the locally maintained candidate UE information list to obtain the updated candidate UE information list. The foregoing is based on the temporary UE information list. The information list is combined with the locally maintained direct communication UE information list to obtain a candidate UE information list. In this embodiment of the present application, how the UE obtains the updated candidate UE information list based on the combination of the updated temporary UE information list and the locally maintained candidate UE information list through the above-mentioned preset rule three will not be described in detail.

The user equipment 100 combines the temporary UE information list 2 of the user equipment 100 and the candidate UE information list 1 of the user equipment 100 based on the above preset rule 3 to obtain the second candidate UE information list of the user equipment 100 as shown in Table 36.

Table 36

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200
用户设备300user equipment 300	在网online	11	用户设备200user equipment 200
用户设备400user equipment 400	在网online	11	用户设备200user equipment 200
用户设备500user equipment 500	在网online	22	用户设备200user equipment 200

The user equipment 200 combines the temporary UE information list 3 and the temporary UE information list 4 of the user equipment 200 with the candidate UE information list 1 of the user equipment 200 based on the above preset rule 3, and obtains the candidate UE 200 as shown in Table 37 UE information list two.

Table 37

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备100user equipment 100	在网online	00	用户设备100user equipment 100
用户设备300user equipment 300	在网online	00	用户设备300user equipment 300
用户设备400user equipment 400	在网online	00	用户设备400user equipment 400
用户设备400user equipment 400	在网online	11	用户设备300user equipment 300
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300
用户设备300user equipment 300	在网online	11	用户设备400user equipment 400
用户设备500user equipment 500	在网online	22	用户设备400user equipment 400

The user equipment 300 combines the temporary UE information list 3 and the temporary UE information list 4 of the user equipment 300 with the candidate UE information list 1 of the user equipment 300 based on the above preset rule 3 to obtain the candidate UE 300 as shown in Table 38 UE information list two.

Table 38

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200
用户设备400user equipment 400	在网online	00	用户设备400user equipment 400
用户设备500user equipment 500	在网online	00	用户设备500user equipment 500
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200
用户设备400user equipment 400	在网online	11	用户设备200user equipment 200
用户设备200user equipment 200	在网online	11	用户设备400user equipment 400
用户设备100user equipment 100	在网online	22	用户设备400user equipment 400

The user equipment 400 combines the temporary UE information list 3 and the temporary UE information list 4 of the user equipment 400 with the candidate UE information list 1 of the user equipment 400 based on the above preset rule 3, and obtains the candidate UE 400 as shown in Table 39 UE information list two.

Table 39

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	在网online	00	用户设备200user equipment 200
用户设备300user equipment 300	在网online	00	用户设备300user equipment 300
用户设备100user equipment 100	在网online	11	用户设备200user equipment 200
用户设备300user equipment 300	在网online	11	用户设备200user equipment 200
用户设备200user equipment 200	在网online	11	用户设备300user equipment 300
用户设备500user equipment 500	在网online	11	用户设备300user equipment 300
用户设备500user equipment 500	在网online	22	用户设备200user equipment 200
用户设备100user equipment 100	在网online	22	用户设备400user equipment 400

The user equipment 500 combines the temporary UE information list 2 of the user equipment 500 and the candidate UE information list 1 of the user equipment 500 based on the above preset rule 3 to obtain the second candidate UE information list of the user equipment 500 as shown in Table 40.

Table 40

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备300user equipment 300	在网online	00	用户设备300user equipment 300
用户设备200user equipment 200	在网online	11	用户设备300user equipment 300
用户设备400user equipment 400	在网online	11	用户设备300user equipment 300
用户设备100user equipment 100	在网online	22	用户设备300user equipment 300

After the UE obtains the updated candidate UE information list, it can receive the heartbeat information of another UE before, but after a certain moment, it cannot receive the heartbeat information of another UE, then the UE can use the updated candidate UE information In the list, another UE is used as the target UE, and the communication status of the communication path whose transit hop count is 0 is changed from on-net to off-net. Or, the heartbeat information of another UE can be received before, but after a certain time, the heartbeat information of another UE cannot be received, then the UE can add the next-hop UEID to the updated candidate UE information list as The communication state of another UE's device identification and the communication path whose transit hop count is greater than 0 is also modified by the on-network and off-network. Then, the arrangement of the communication paths in the candidate UE information list is adjusted smoothly, and the path information of the on-network communication paths is arranged before the path information of the off-network communication paths.

Exemplarily, at a certain moment, the distance between the user equipment 200 and the user equipment 300 exceeds the distance that can be directly communicated, then the user equipment 200 cannot receive the heartbeat message sent by the user equipment 300, and the user equipment 300 cannot receive the heartbeat message. A heartbeat message sent by the user equipment 200. Then the communication topology shown in FIG. 2 becomes the communication topology shown in FIG. 3A. The double-headed arrows shown in FIG. 2 and FIG. 3A indicate that the distance between two devices is within the direct communication distance, and the two devices can send and receive data to each other.

In the communication topology shown in FIG. 3A , direct communication between the user equipment 200 and the user equipment 300 is impossible, so the user equipment 200 cannot receive the heartbeat message sent by the user equipment 300, and the user equipment 300 cannot receive the heartbeat message sent by the user equipment 200. heartbeat message. In this case, the user equipment 200 will update the second candidate UE information list of the user equipment 200 to obtain the third candidate UE information list of the user equipment 200 as shown in Table 41 .

Table 41

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备100user equipment 100	在网online	00	用户设备100user equipment 100
用户设备300user equipment 300	离网Off-grid	00	用户设备300user equipment 300
用户设备400user equipment 400	在网online	00	用户设备400user equipment 400
用户设备400user equipment 400	离网Off-grid	11	用户设备300user equipment 300
用户设备500user equipment 500	离网Off-grid	11	用户设备300user equipment 300
用户设备300user equipment 300	在网online	11	用户设备400user equipment 400
用户设备500user equipment 500	在网online	22	用户设备400user equipment 400

As shown in Table 41, the user equipment 200 changes the communication status of the target UE whose target UE is the user equipment 300 and whose transit hop count is 0 in the candidate UE information list 2 of the user equipment 200 to off-network. It is also necessary to change the communication state of the communication path whose next hop UEID is the user equipment 300 and whose transit hop count is greater than 0 to off-network, as shown in Table 41.

Similarly, the user equipment 300 also needs to update the second candidate UE information list of the user equipment 300 to obtain the third candidate UE information list of the user equipment 300 as shown in Table 42 .

Table 42

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE	中转跳数transit hops	下一跳UEIDnext hop UEID
用户设备200user equipment 200	离网Off-grid	00	用户设备200user equipment 200
用户设备400user equipment 400	在网online	00	用户设备400user equipment 400
用户设备500user equipment 500	在网online	00	用户设备500user equipment 500
用户设备100user equipment 100	离网Off-grid	11	用户设备200user equipment 200
用户设备400user equipment 400	离网Off-grid	11	用户设备200user equipment 200
用户设备200user equipment 200	在网online	11	用户设备400user equipment 400
用户设备100user equipment 100	在网online	22	用户设备400user equipment 400

As shown in Table 42, the user equipment 300 modifies the communication status of the target UE whose target UE is the user equipment 200 and whose transit hop count is 0 in the candidate UE information list 2 of the user equipment 300 to off-network. It is also necessary to change the communication state of the communication path whose next hop UEID is the user equipment 200 and whose transit hop count is greater than 0 to off-network, as shown in Table 42.

Furthermore, since the user equipment 200 and the user equipment 300 are Relay UEs, the user equipment 200 and the user equipment 300 need to obtain the target UE information list based on the candidate UE information list 3, and obtain the updated relay relay based on the preset rule 1 screening. The UE information list is then broadcast to other UEs. In this way, other UEs can update the path information to other target UEs in real time according to the transfer UE information list. Specifically, how to obtain the target UE information list based on the candidate UE information list 3, obtain the updated transfer UE information list based on the target UE information list, and how other UEs update the candidate UE information list according to the transfer UE information list. Referring to relevant descriptions in the foregoing embodiments, the embodiments of the present application are not described again here.

In this way, through the above method, the UE in the D2D network monitors the communication status and communication path information of the target UE that can communicate in real time by maintaining a candidate UE information list. In this way, each UE can communicate with the target UE based on the locally maintained candidate UE information list.

Next, in a D2D network of multiple Relay UEs, how to send unicast message 1 between two UEs, unicast message 1 includes business data, first source UEID, first target UEID, first relay UEID, Wherein, the first source UEID is used to indicate the device identity of the service data sender, the first target UEID is used to indicate the device identity of the service data receiver, and the first transit UEID is used to indicate the communication between the first UE and the service data receiver UEID of the next hop in the path. When the current UE sends a unicast message to the target UE, the current UE may be the sender of the service data or the forwarder of the service data.

Messages can be sent between two UEs based on the following steps.

Step 1: The current UE finds the same communication path as the target UE in the locally maintained candidate UE information list or target UE information list.

If the current UE does not find the same communication path as the target UE in the locally maintained candidate UE information list or target UE information list, it means that the current UE cannot communicate with the target UE, and the unicast information is discarded.

If the current UE finds the same communication path as the target UE in the locally maintained candidate UE information list or the target UE information list, but the communication status of the target UE in the communication path is off-network, cache the unicast message one, and After a period of time, the current UE searches for the same communication path as the target UE in the locally maintained candidate UE information list or target UE information list until the communication status in the same communication path as the target UE is online. The current UE sends the unicast message 1 to the target UE based on step 2.

It should be noted that the current number of unicast messages buffered by the UE shall not be greater than the preset number. If the number of unicast messages cached by the current UE is greater than the preset number after the current UE caches the unicast message, the current UE discards the earliest cached unicast message.

The time of the same unicast message buffered by the current UE shall not be longer than the preset time. If the current UE caches the unicast message 1 for a preset time, but the communication state in the same communication path as the target UE is still off-network, the current UE discards the unicast message 1.

Step 2: If the current UE finds the same communication path as the target UE in the candidate UE information list or target UE information list maintained locally by the current UE, judge whether the transit hop count is 0.

If the transit hop count is 0, the current UE determines the first transit UEID of the unicast message 1 as null or the device identifier of the target UE, and the current UE sends the unicast message 1 to the target UE.

If the number of transit hops is greater than 0, the first transit UEID in the unicast message 1 is determined as the next-hop UEID in the communication path, and the current UE sends the unicast message 1 to the next-hop UEID in the communication path.

It should be noted that the current UE may find two or more than two communication paths to the target UE from the candidate UE information list maintained locally by the current UE, so in some embodiments, the current UE may send the unicast message to They are respectively sent through two or more than two communication paths reaching the target UE, so that the reliability of sending the unicast message can be guaranteed.

Next, it will be introduced how the current UE sends the unicast message 1 based on the communication path to the target UE.

If the current UE is the sender of the service data, then the first source UEID is the device identifier of the current UE. Before the current UE sends unicast message 1, based on the first target UEID, find the communication path between the first UE and the service data receiver from the candidate UE information list or target UE information list maintained by the current UE; if the communication If the number of transit hops in the path is 0, the first transit UEID in unicast message 1 is set to be empty or the target UEID; if the transit hop count in the communication path is greater than 0, the first transit UEID in unicast message 1 The transit UEID is determined as the next-hop UEID in the communication path.

If the current UE is not the sender of the service data but the forwarder of the service data, then the current UE needs to receive the unicast message 2 sent by other UEs before sending the unicast message 1. Unicast message 2 includes service data, a second source UEID, a second target UEID, and a second transit UEID; wherein, the second source UEID is used to indicate the device identity of the sender of the service data, and the second target UEID is used to indicate the service data receiving The device identifier of the party, and the second relay UEID is the device identifier of the current UE. Afterwards, the current UE generates unicast message 1 based on unicast message 2. Specifically, based on the second target UEID in the unicast message 2, the current UE finds the communication path between the unicast message 2 and the service data receiver; if the number of transit hops in the communication path is 0, the unicast The first transit UEID in message one is determined to be empty or the target UEID; if the transit hop count in the communication path is greater than 0, then determine the first transit UEID in unicast message one as the next UEID in the communication path Jump UEID.

This embodiment of the present application is described by taking the user equipment 200 sending a unicast message 1 to the user equipment 500 as an example. Then the first target UEID in the unicast message one is the device identifier of the user equipment 500 .

When the user equipment 200 is the forwarder of the first unicast message, the first target UEID in the first unicast message is the device identifier of the user equipment 500 . Before the user equipment 200 sends the first unicast message, it first receives the second unicast message. The second unicast message includes service data, a second source UEID, a second target UEID, and a second transit UEID; the second source UEID is used to indicate the device identifier of the sender of the service data, and the second target UEID is the device identifier of the user equipment 500, The second transit UEID is the device identifier of the user equipment 200 . Afterwards, the user equipment 200 generates a unicast message 1 based on the unicast message 2 . Specifically, based on the target UE being the device identifier of the user equipment 500, the user equipment 200 finds the communication path where the target UE is the user equipment 500 from the candidate UE information list or the target UE information list of the user equipment 200, for example, the table The fifth communication path shown in 37. The transit hop count of the fifth communication path shown in Table 37 is 1, and the first transit UEID in the unicast message one determines the device identifier of the user equipment 300 . Afterwards, the user equipment 200 sends the unicast message one to the next-hop UEID in the fifth communication path shown in Table 37, that is, the user equipment 300.

When the user equipment 200 is the sender of the first unicast message, the first source UEID in the first unicast message is the device identifier of the user equipment 200 , and the first target UEID is the device identifier of the user equipment 500 . Before the user equipment 200 sends the unicast message 1, the user equipment 200 finds the communication path whose target UE is the user equipment 500 from the candidate UE information list 2 of the user equipment 200, for example, the fifth communication path shown in Table 37 . The transit hop count of the fifth communication path shown in Table 37 is 1, and the first transit UEID in the unicast message one determines the device identifier of the user equipment 300 . Afterwards, the user equipment 200 sends the unicast message one to the next-hop UEID in the fifth communication path shown in Table 37, that is, the user equipment 300 .

Optionally, the current UE may send the service data in a broadcast form. In addition to service data, the broadcast message also includes source UEID and target UEID. The source UEID is the device identifier of the current UE, and the destination UEID is the broadcast identifier. After that, the current UE directly sends the broadcast message containing the service data in the form of broadcast.

Optionally, the current UE can send service data in the form of multicast, then in addition to the service data, the multicast message also includes source UEID and target UEID, the source UEID is the device identifier of the current UE, and the destination UEID is the multicast identifier , and then the current UE directly sends out the multicast message including the service data in the form of multicast. If the target UEID also includes a target UE whose corresponding hop count is greater than 0 in the target UE information list or candidate UE information list of the current UE, the current UE can convert the multicast message into a unicast message format as needed, Send the message containing the service data to those target UEs whose hop count is greater than 0 according to the sending mode of the unicast message.

Based on the first embodiment, as shown in FIG. 3B , this embodiment of the present application provides another schematic diagram of a communication topology.

As shown in FIG. 3B, the difference between FIG. 3B and FIG. 2 is that the user equipment 300 in FIG. 3B can also communicate with the base station 600, and the user equipment 100, the user equipment 200, the user equipment 400, and the user equipment 500 cannot communicate with the base station. , that is, in an area where there is no cellular signal or the cellular signal is relatively poor. In this way, other user equipments shown in FIG. 3B that cannot communicate with the base station can communicate with the base station 600 based on the user equipment 300 .

Specifically, if the user equipment 300 in FIG. 3B can communicate with the base station 600, then a new parameter information needs to be added to the transit UE information list maintained by the user equipment 300, that is, the network identification, and the candidate information maintained by the user equipment in FIG. 3B It is also necessary to add a new parameter information in the UE information list, that is, the network identification. The networking identification user indicates that the target UE has established a connection with the base station. The candidate UE information list may be expressed as (device identifier of the target UE, network status of the target UE, number of transit hops, next-hop UEID, networking identifier of the target UE). Wherein, the communication state of the target UE includes an on-net state or an off-net state. The online state is used to indicate that the target UE is in the power-on state, and further, the target UE in the power-on state can directly communicate with other UEs or indirectly communicate with other UEs by forwarding data through the Relay UE. The off-grid state is a power-off state, and further target UEs in the power-off state cannot directly communicate with other UEs or indirectly communicate with other UEs through relay UE forwarding data.

The networking identifier of the target UE indicates whether the target UE is connected to the base station. If the target UE is connected to the base station, then the networking identifier of the target UE may be represented as 1, and if the target UE cannot be connected to the base station, then the networking identifier of the target UE may be represented as 0.

Then the second candidate UE information list maintained by the user equipment 200 may be expressed as a candidate UE information list as shown in Table 43 below.

Table 43

As shown in Table 43, since the user equipment 300 has established a communication connection with the base station 600, that is, the user equipment 300 can use the cellular network to communicate with other UEs that are not within the communication range. Then in Table 43, the networked state in the communication path where the target UE is the user equipment 300 is only identified as “1”, and the networked state as “1” means that the user equipment 300 has established a communication connection with the base station 600 .

When the user equipment 200 communicates with other UEs (such as user equipment 700) in the cellular network where the base station 600 is located through the user equipment 300, the user equipment 700 is not shown in FIG. 3B, and the user equipment 700 cannot communicate with the UE shown in FIG. 3B Any UE in the network topology communicates directly, but the user equipment 700 can communicate with the user equipment 300 through the base station 600 .

Assuming that user equipment 200 wants to send unicast message 1 to user equipment 700, unicast message 1 not only includes service data, source UEID, target UEID and transit UEID, but also includes the address of user equipment 700 in the cellular network. In this way, the user equipment 200 can communicate with the user equipment 700 through the user equipment 300 . Specifically, how the user equipment 200 sends the unicast message 1 can refer to the description in the foregoing embodiments, and details are not repeated in this embodiment of the present application.

Optionally, the user equipment 300 adds a new parameter information in the transit UE information list maintained by the user 300, that is, the network identification. The user equipment 300 may not add a networking identifier to the maintained relay UE information list, but may add a new piece of path information in the relay UE information list, and the path information is used to indicate the communication path between the user equipment 300 and the base station 600 . The parameter information between the user equipment 300 and the base station 600 includes the device identifier of the target device, the communication status of the target device, the number of transit hops, and the UEID of the next hop. Then the parameter information between the user equipment 300 and the base station 600 is specifically that the device identifier of the target device is the cell identifier of the base station 600, the communication status is online, the number of transit hops and the UEID of the next hop are all empty. The cellular identity may be composed of the equipment identity of the user equipment 300 concatenated with a fixed ID, for example, the user equipment 300+fixed ID. The fixed ID is used to identify the public network of the base station 600, such as 0x0000.

Then the transfer UE information list of the user equipment 300 can be represented as shown in Table 44.

Table 44

Wherein, the user equipment 300+fixed ID can be understood as the identity of the base station 600 . The last item in the relay UE information list indicates that the user equipment 300 can directly communicate with the base station 600 .

The user equipment 300 broadcasts the relay UE information list to other UEs, and the user equipment 200 generates a candidate UE information list as shown in Table 45 after receiving the relay UE information list of the user equipment 300 .

Table 45

The last item in the relay UE information list indicates that the user equipment 200 can communicate with the base station 600 through the user equipment 300 .

Assuming that the user equipment 200 wants to send a unicast message 1 to the user equipment 700, the unicast message 1 includes service data, source UEID, target UEID and transit UEID. In this way, the user equipment 200 can communicate with the user equipment 700 through the user equipment 300 . When the user equipment 200 wants to send a unicast message, firstly, from the target UE information list or the candidate UE list of the user equipment 200, a target UE is selected as a communication path whose communication status is "on-network" and the number of transit hops is the smallest in the communication path with the cell identification. Then remove the fixed ID part of the cell identity, and use the remaining content as a target UE ID, and fill in the target UE ID in unicast message 1 as the remaining content. Then send unicast message 1 according to the above method. Specifically, how the user equipment 200 sends the unicast message 1 can refer to the description in the foregoing embodiments, and details are not repeated in this embodiment of the present application.

Embodiment two

The scenario involved in the second embodiment is a scenario where there is only one Relay UE in the D2D network.

In Embodiment 1, the UE receives heartbeat information continuously sent by other UEs to generate a direct communication UE information list. For the Relay UE, the Relay UE will generate a relay UE information list based on the direct communication UE information list, and the Relay UE will broadcast the relay UE information list and the device identifier of the Relay UE to other UEs. After receiving the relay UE information list of the relay UE, other UEs maintain the direct communication UE information list and the relay UE information list locally. There is no need to combine the direct communication UE information list and the transfer UE information list. Because in a D2D network with only one Relay UE, two devices can either communicate directly, or communicate through the Relay UE to forward a message once. Therefore, if the two UEs can communicate, the current UE can either find the communication path to the target UE from the locally maintained direct communication information list; if the locally maintained direct communication UE information list does not find the communication path to the target UE , then the former UE can search the communication path to the target UE from the relay UE information list sent by the Relay UE. Therefore, the UE does not need to combine the direct communication UE information list and the relay UE information list, reducing the calculation amount of the UE.

As shown in FIG. 4 , FIG. 4 exemplarily shows a schematic structural diagram of another communication system 400 . The communication system 400 may include user equipment 100 , user equipment 200 , user equipment 300 , user equipment 400 and user equipment 500 . Wherein, the user equipment 100, the user equipment 200, the user equipment 400 and the user equipment 500 are non-Relay UEs, and the user equipment 300 is a Relay UE. That is to say, the user equipment 100, the user equipment 200, the user equipment 400 and the user equipment 500 cannot forward data, but the user equipment 300 can forward data. For example, in the case that the user equipment 200 can communicate with the user equipment 500, the user equipment 300 can receive the data sent by the user equipment 200, and the user equipment 300 forwards the data sent by the user equipment 200 to the amount Hebi 500. It should be understood that the communication system 400 to which the method of the embodiment of the present application can be applied may include more or fewer user equipments.

Based on the schematic structural diagram of a communication system 400 provided in FIG. 4 , how each UE maintains a direct UE information list or a relay UE information list in a scenario where there is only one Relay UE in a D2D network will be described below.

The direct communication UE information list includes the equipment identification of the target UE, the communication status of the target UE, the number of transit hops and the equipment identification (user equipment identification, UEID) of the next-hop user equipment, the communication status of the target UE is on-net or off-net, The next-hop UEID is used to indicate the device identity of the user equipment adjacent to the current UE in the communication path between the current UE and the target UE. For example, the user equipment 100 receives the heartbeat information sent by the user equipment 200 to generate the direct communication UE information list of the user equipment 100 . The user equipment 200 receives the heartbeat information sent by the user equipment 100 and the user equipment 300 to generate a direct communication UE information list of the user equipment 200 . The user equipment 300 receives the heartbeat information sent by the user equipment 200 , the user equipment 400 and the user equipment 500 to generate a direct communication UE information list of the user equipment 300 . The user equipment 400 receives the heartbeat information sent by the user equipment 300 to generate a direct communication UE information list of the user equipment 400 . The user equipment 500 receives the heartbeat information sent by the user equipment 300 to generate a direct communication UE information list of the user equipment 500 .

Since the transit hop number in the direct communication UE information list is 0, and the next-hop UEID is the same as the target UE device identifier, the transit hop count and the next-hop UEID may not be recorded in the direct communication UE information list, saving the direct maintenance of the UE. The memory occupied by the communication UE information list. Then the direct communication UE information list may only include the device identifier of the target UE and the communication status of the target UE.

Table 46

Table 46 exemplarily shows the direct communication UE information list of the user equipment 100 . Table 43 may be expressed as (user equipment 200, on-net).

Table 47

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE
用户设备100user equipment 100	在网online
用户设备300user equipment 300	在网online

Table 47 exemplarily shows the direct communication UE information list of the user equipment 200. Table 44 may be expressed as (user equipment 100, on-net), (user equipment 300, on-net).

Table 48

目标UE的设备标识Device identity of the target UE	目标UE的通信状态Communication status of the target UE
用户设备200user equipment 200	在网online
用户设备500user equipment 500	在网online
用户设备400user equipment 400	在网online

Table 48 exemplarily shows the direct communication UE information list of the user equipment 300 . Table 45 may be expressed as (user equipment 200, online), (user equipment 500, online), (user equipment 400, online).

Table 49

Table 49 exemplarily shows the direct communication UE information list of the user equipment 400 . Table 46 may be expressed as (user equipment 300, on-net).

Table 50

Table 50 exemplarily shows a list of direct communication UE information of user equipment 500 . Table 47 may be expressed as (user equipment 300, on-net).

Exemplarily, the user equipment 300 needs to obtain the transfer UE information list based on the obtained direct communication UE information list. The user equipment 300 may obtain the transfer UE information list of the user equipment 300 by filtering from the direct communication UE information list of the user equipment 300 based on the preset rule introduced in the embodiment. For the introduction of the preset rule 1, reference may be made to the related description in the first embodiment, which will not be repeated here in the embodiment of the present application.

Table 51

Table 51 exemplarily shows a list of relay UE information of user equipment 300 . Table 48 may be expressed as (user equipment 200, online), (user equipment 500, online), (user equipment 400, online).

Optionally, after the Relay UE detects a change in the local relay UE information list, it sends the updated complete relay UE information list and the device identifier of the Relay UE to other UEs by broadcasting.

Exemplarily, it is assumed that the relay UE information list obtained by the user equipment 300 in the communication system 400 is the same as the direct communication UE information list of the user equipment 300 , that is, the communication path in the direct communication UE information list of the user equipment 300 is not deleted. Afterwards, the user equipment 300 broadcasts the transfer UE information list of the user equipment 300 to other UEs. All other UEs within the communication range with the user equipment 300 can receive the transfer UE information list of the user equipment 300 . For example, user equipment 200 may receive the relay UE information list of user equipment 300, user equipment 400 may receive the relay UE information list of user equipment 300, and user equipment 500 may receive the relay UE information list of user equipment 300.

After receiving the transfer UE information list, other UEs save the transfer UE information list locally, and other UEs maintain the transfer UE information list and the direct communication UE information list to detect the communication status of the target UE in real time. UEs that have not received the relay UE information list are only used to maintain the direct communication UE information list to detect the communication status of the target UE in real time.

The following describes how to send unicast message 1 between two UEs in a D2D network with only one Relay UE. Unicast message 1 includes service data, first source UEID, first target UEID, and first relay UEID. Among them, The first source UEID is used to indicate the device identity of the service data sender, the first target UEID is used to indicate the device identity of the service data receiver, and the first transit UEID is used to indicate the communication path from the first UE to the service data receiver Next hop UEID. When the current UE sends a unicast message to the target UE, the current UE may be the sender of the service data or the forwarder of the service data.

There are two situations in which the current UE sends a message to the target UE: Case 1: the current UE only maintains a direct communication UE information list. Case 2: The current UE needs to maintain a transfer UE information list and a direct communication UE information list.

Firstly, it is introduced how the current UE sends a unicast message to the target UE when the current UE only maintains the UE information list for direct communication.

In the case that the current UE only maintains the direct communication UE information list, the current UE may be the sender of the unicast message one. The current UE finds the communication path containing the target UE in the locally maintained direct communication information list, then the first transit UEID can be determined to be empty or determined to be the device identifier of the target UE, and then the current UE sends a unicast message to the target UE. If the current UE does not find the communication path containing the target UE in the direct communication information list maintained locally or finds the communication path of the target UE, but the communication status of the target UE is off-network, buffer the unicast message one, every At this time, the current UE searches for the same communication path as the target UE in the locally maintained communication UE information list until the communication status of the same communication path as the target UE is online. The current UE sends a unicast message to the target UE.

Then it introduces how the current UE sends a unicast message to the target UE when the current UE maintains the direct communication UE information list and the transfer UE information list at the same time.

If the current UE is the sender of unicast message 1. If the current UE finds a communication path containing the target UE in the locally maintained direct communication information list, then the first transit UEID can be determined to be empty or determined to be the device identifier of the target UE, and then the current UE sends a unicast message to Target UE. If the current UE does not find a communication path containing the target UE in the locally maintained direct communication information list, but the current UE searches for the same communication path as the target UE in the locally maintained transit UE information list, and the communication status of the target UE is In the network, the current UE determines the device identity of the Relay UE with the first relay UEID. If the current UE does not find the communication path containing the target UE in the direct communication information list maintained locally, and does not find the same communication path as the target UE in the transit UE information list maintained locally by the current UE, buffer the unicast message 1. Every once in a while, the current UE searches for the same communication path as the target UE in the locally maintained information list of the connecting UE or the information list of the transit UE. If the current UE finds a communication path containing the target UE in the locally maintained direct communication UE information list or transit UE information list, but the communication status of the target UE is off-network, cache the unicast message 1, every once in a while, until The current UE searches for the same communication path as the target UE in the locally maintained communication UE information list or transit UE information list, and the communication status of the target UE is online, and sends unicast message one.

If the current UE is the forwarder of the unicast message 1. Then the steps of the current UE sending the unicast message 1 are similar to the method steps of the current UE sending the unicast message 1 under the condition that the current UE only maintains the UE information list for direct communication, and will not be repeated here in this embodiment.

If the current UE cannot find the communication path of the target UE in both the direct communication list and the transfer information list, the current UE cannot communicate with the target UE.

It should be noted that the current number of unicast messages buffered by the UE shall not be greater than the preset number. If the number of unicast messages cached by the current UE is greater than the preset number after the current UE caches the first unicast message, the current UE discards the earliest cached unicast message.

Optionally, the current UE can send service data in the form of multicast, then in addition to the service data, the multicast message also includes source UEID and target UEID, the source UEID is the device identifier of the current UE, and the destination UEID is the multicast identifier , and then the current UE directly sends out the multicast message including the service data in the form of multicast. If the target UEID does not include the target UE in the current UE's direct communication UE information list, the current UE can convert the multicast message into a unicast message format according to the needs, and send the message containing the service according to the sending method of the unicast message. Data messages are sent to the target UE.

Based on the first and second embodiments, the UE can monitor the communication state of the target UE and the path information of the communication path in real time by maintaining the list information. In combination with Embodiment 1 and Embodiment 2, further, the Relay UE may add the version number of the relay UE information list to the heartbeat message continuously sent, and the version number of the relay UE information list in the heartbeat message is used for other UEs to determine Whether the received is the latest transit UE information list.

As shown in Figure 5, Figure 5 exemplarily shows a flow chart of how to confirm that the received transfer UE information list is the latest version.

S501. Receive a first transfer UE information list sent by a first UE.

The first UE may be any one of the user equipment 200, the user equipment 300, and the user equipment 400 described in the first embodiment, and the first UE may also be the user equipment 300 described in the second embodiment.

The first transfer UE information list may be the transfer UE information list 1 or transfer UE information list 2 of the user equipment 200 described in the first embodiment, the transfer UE information list 1 or transfer UE information list 2 of the user equipment 300 and the user equipment 400 Any one of the relay UE information list 1 or the relay UE information list 2, the first relay UE information list may also be the relay UE information list of the user equipment 300 described in the second embodiment.

Wherein, the first transfer UE information list includes the path information of the first communication path between the first UE and the second UE, and the second UE is the target UE;

Optionally, the first relay UE information list also includes the communication status of the second UE, the number of transfer hops for data transmission in the first communication path, and the device identifier of the next-hop UE of the first UE in the first communication path UEID.

Optionally, the first relay UE information list further includes the networking identifier of the second UE. Wherein, the networking identifier is used to indicate whether the second UE establishes a connection with the base station, that is, whether the second UE can be connected to the network.

S502. Receive first heartbeat information sent by the first UE, where the first heartbeat information includes a device identifier and a first version number of the first UE.

It can be understood that the first UE sends the first heartbeat information continuously (for example, 5 seconds is a cycle). The first heartbeat information includes the device identifier and the first version number of the first UE. Wherein, the first version number is used to confirm whether the received first transfer UE information list is the latest transfer UE information list.

The version number of the relay UE information list will change with the update of the relay UE information list. Therefore, after the relay UE information list is updated, the version number of the corresponding relay UE information list will also change. For example, each time the relay UE information list changes, the value of the version number of the relay UE information list is increased by 1.

Specifically, based on the first version number, it is confirmed whether the received first transfer UE information list is the latest transfer UE information list sent in the following two ways:

Mode 1: The first transit UE information list sent by the first UE also needs to include a version number. For example, the first transfer UE information list includes the second version number, and when the first version number is the same as the second version number, it is determined that the first transfer UE information list is the latest transfer UE information list. When the first version number is different from the second version number, it is determined that the first transfer UE information list is not the latest transfer UE information list.

Mode 2: The first transit UE information list sent by the first UE does not include a version number. Before receiving the first relay UE information list sent by the first UE, the second heartbeat message sent by the first UE is also received. The second heartbeat message also includes the third version number and the device identifier of the first UE. Optionally, the second heartbeat information is heartbeat information adjacent to the first relay UE information list. For the first UE, the first UE needs to send the heartbeat message first, and then send the relay UE information list immediately afterwards. If the third version number is the same as the first version number, it means that the first transfer UE information list is the latest transfer UE information list. When the third version number is different from the first version number, it is determined that the first transfer UE information list is not the latest transfer UE information list.

The above method 1 and method 2 are used to determine whether it is the latest relay UE information list, which is applicable to the scenario of one Relay UE and multiple Relay UEs. However, for a scenario where there is only one Relay UE, the embodiment of the present application also provides another method for confirming whether it is the latest relay UE information list.

Specifically, in a Relay UE scenario, the Relay UE can load the version number of the relay UE information list into the relay UE information list and send it out. Then other UEs (i.e. non-Relay UEs) store the version number in the relay UE information list locally after receiving the relay UE information list including the version number of the relay UE information list. Afterwards, the non-Relay UE loads the version number sent by the Relay UE into its own heartbeat message and sends it out by broadcasting. After receiving the heartbeat message sent by the non-Relay UE, the Relay UE will confirm whether the version number in the heartbeat message sent by the non-Relay UE is consistent with the version number in the transmitted relay UE information list. If they are inconsistent, the Relay UE will actively send the latest version of the relay UE information list to the non-Relay UE. If they are consistent, it means that the non-Relay has received the latest version of the latest version of the relay UE information list, so the Relay UE does not need to send the latest version. The list of transit UE information.

Optionally, after receiving the second heartbeat message sent by the first UE, before receiving the first transfer UE information list sent by the first UE, the method further includes: before receiving the second heartbeat message, not receiving The first relay UE information list, the third time after receiving the second heartbeat message, did not receive the first relay UE information list, that is, the heartbeat message including the version number can be received, but the first UE has never received the first UE information list. The transfer UE information list, then send a second request to the first UE, where the second request is used to instruct the first UE to send the first transfer UE information list.

Optionally, after receiving the first transit UE information list sent by the first UE, the first heartbeat message sent by the first UE is not received before a certain time, and the first transit UE information list may also be considered to be the latest, Then the first unicast message may be sent based on the first relay UE information list. After a certain period of time, if the first heartbeat message sent by the first UE is still not received, the first unicast message is not sent based on the first relay UE information list.

S503. When it is confirmed based on the first version number that the first relay UE information list is an updated relay UE information list, send first unicast information based on the first relay UE information list.

The first unicast information may be the first unicast information described in Embodiment 1 or Embodiment 2.

It can be known from S502 that when it is confirmed based on the first version number that the first relay UE information list is an updated relay UE information list, the first unicast information is sent based on the first relay UE information list. The first unicast information includes service data, UEID of the source user equipment, target UEID, and transit UEID.

When it is confirmed based on the first version number that the first transfer UE information list is not an updated transfer UE information list, a first request is sent to the first UE, and the first request is used to instruct the first UE to send an updated transfer UE information list; receiving the second An updated relay UE information list sent by the UE, the updated relay UE information list includes path information of a second communication path between the first UE and the third UE; sending second unicast information based on the updated relay UE information list. Wherein, the third UE may be the same as or different from the second UE.

Optionally, the first request is sent to the first UE if the updated transfer UE information list has not been received within a first time after receiving the first heartbeat information. In this way, after it is determined that the first transfer UE information list is not the latest transfer UE information list, wait for the first time before sending the request, so as to avoid the problem of repeated sending due to network delay.

Optionally, after receiving the first heartbeat information sent by the first UE, the method further includes: not receiving an updated heartbeat message sent by the first UE within a second time, passing through the communication path in the communication path of the first UE The state is changed from on-net to off-net, or the communication state in the communication path with the first UE as the next-hop UE is changed from on-net to off-net. In this way, when the updated heartbeat message sent by the first UE cannot be received, it is impossible to directly communicate with the first UE, and the communication status of the first UE is changed from on-net to off-net, or the first UE The communication status in the communication path of the UE as the next hop UE is changed from on-net to off-net. In this way, the communication state of the target UE can be updated in real time.

It should be noted that when the information in the candidate UE information list maintained by the UE or the information in the target UE information list changes, it needs to actively request the Relay UE to send the relay UE information list to itself, so that the UE can update the candidate UE according to the relay UE information list information in the information list. Until the relay UE information list of all relay UEs that can communicate directly is received. Here, it can be determined which UEs that can communicate directly are relay UEs that can communicate directly based on the version number in the heartbeat message sent by the relay UE. Specifically, the heartbeat message of the relay UE capable of direct communication carries the version number, and the heartbeat message of the non-relay UE capable of direct communication does not carry the version number.

FIG. 6 is a schematic structural diagram of a communication device 600 provided by an embodiment of the present application. These communication apparatuses 600 can be used to implement the functions of the user equipment in the above method embodiments, and therefore can also realize the beneficial effects of the above method embodiments. In the embodiment of the present application, the communication device may be any kind of user equipment as shown in FIG. 2, or any kind of user equipment as shown in FIG. 3A and FIG. , any module (such as a chip) of the user equipment shown in FIG. 3A and FIG. 3B .

As shown in FIG. 6 , a communication device 600 includes a sending unit 601 , a receiving unit 602 and a processing unit 603 . The communications apparatus 600 is configured to implement the functions of any one of the user equipments in Embodiment 1 or Embodiment 2 above. When the communication device 600 is used to implement the functions of any user equipment in the first or second embodiment above: the receiving unit 602 is configured to receive the first transfer UE information list sent by the first UE; wherein, the first transfer UE The information list includes the path information of the first communication path between the first UE and the second UE, and the second UE is the target UE; receiving the first heartbeat information sent by the first UE, and the first heartbeat information includes the device identifier of the first UE and the first version number, the first version number is used to confirm whether the first transfer UE information list is an updated transfer UE information list; the sending unit 601 is used to confirm that the first transfer UE information list is an updated transfer UE information list based on the first version number When the UE information list is used, the first unicast information is sent based on the first relay UE information list.

Optionally, the first transit UE information list further includes the communication status of the second UE, the number of transit hops for data transmission in the first communication path, and the UEID of the next-hop UE of the first UE in the first communication path.

Optionally, the first relay UE information list further includes the networking identifier of the second UE.

The first unicast message includes service data, UEID of the source user equipment, target UEID, and transit UEID.

The sending unit 601 is further configured to send a first request to the first UE when it is confirmed based on the first version number that the first transfer UE information list is not an updated transfer UE information list, and the first request is used to instruct the first UE to send an updated transfer UE information list. Transit UE information list;

The receiving unit 602 is further configured to receive an updated transfer UE information list sent by the first UE, where the updated transfer UE information list includes path information of a second communication path between the first UE and the third UE;

The sending unit 601 is further configured to send first unicast information based on the updated transfer UE information list

The sending unit 601 is further configured to send a first request to the first UE when the updated transfer UE information list has not been received within a first time after receiving the first heartbeat information.

The first relay UE information list includes the second version number. The processing unit 603 is configured to compare the first version number with the second version number, so as to confirm based on the first version number that the first transfer UE information list is an updated transfer UE information list.

The receiving unit 602 is further configured to receive a second heartbeat message sent by the first UE; the second heartbeat message includes the device identifier and the third version number of the first UE;

The processing unit 603 is further configured to compare the first version number with the third version number, so as to confirm based on the first version number that the first transfer UE information list is an updated transfer UE information list.

The processing unit 603 is further configured to change the communication status of the first UE from on-net to off-net if the update heartbeat message sent by the first UE is not received within the second time, or to use the first UE as the next-hop UE The communication status in the communication path of the network is changed from on-net to off-net.

The processing unit 603 is further configured to, before receiving the second heartbeat message, if the first transfer UE information list is not received, and at the third time after receiving the second heartbeat message, the first transfer UE information list is not received, and report to the second A UE sends a second request, and the second request is used to instruct the first UE to send the first relay UE information list.

The processing unit 603 is further configured to, after receiving the first transit UE information list sent by the first UE, if the first heartbeat message sent by the first UE is not received before a certain time, the first transit UE information list can also be regarded as is the latest, then the first unicast message may be sent based on the first relay UE information list. After a certain period of time, if the first heartbeat message sent by the first UE is still not received, the first unicast message is not sent based on the first relay UE information list.

It should be understood that any of the above units may be implemented by software, hardware or a combination of both, which is not limited in this embodiment.

As shown in FIG. 7 , a communication device 700 includes a processor 701 , an interface circuit 702 and a bus 703 . The processor 701 and the interface circuit 702 are coupled to each other. It can be understood that the interface circuit 702 may be a transceiver or an input-output interface. Optionally, the communication device 700 may further include a memory 704 for storing instructions executed by the processor 701 or storing input data required by the processor 701 to execute the instructions or storing data generated after the processor 701 executes the instructions.

When the communication device 700 is used in the method shown in FIG. 5 , the processor 701 is used to realize the functions of the processing unit 603 , and the interface circuit 702 is used to realize the functions of the sending unit 601 and the receiving unit 602 .

When the foregoing communication device is a chip applied to the first UE, the chip of the first UE is used to realize the functions of the first UE in the foregoing method embodiment. The chip of the first UE receives information from other modules (such as radio frequency modules or antennas) in the first UE, and the information is sent to the first UE by other UEs; or, the chip of the first UE sends information to the first UE Other modules (such as radio frequency modules or antennas) send information, and the information is sent by the first UE to other UEs.

It can be understood that the processor in the embodiments of the present application can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application-specific integrated circuits (Application Specific Integrated Circuit, ASIC), Field Programmable Gate Array (Field Programmable Gate Array, FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. A general-purpose processor can be a microprocessor, or any conventional processor.

The method steps in the embodiments of the present application may be implemented by means of hardware, or may be implemented by means of a processor executing software instructions. Software instructions can be composed of corresponding software modules, and software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only Memory, registers, hard disk, removable hard disk, CD-ROM or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be a component of the processor. The processor and storage medium can be located in the ASIC. In addition, the ASIC can be located in a network device or a terminal device. Certainly, the processor and the storage medium may also exist in the network device or the terminal device as discrete components.

In the above embodiments, all or part of them may be implemented by software, hardware, firmware or any combination thereof. When implemented using software, it may be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer programs or instructions. When the computer program or instructions are loaded and executed on the computer, the processes or functions described in the embodiments of the present application are executed in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, network equipment, user equipment, or other programmable devices. The computer program or instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer program or instructions may be downloaded from a website, computer, A server or data center transmits to another website site, computer, server or data center by wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server or a data center integrating one or more available media. The available medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; it may also be an optical medium, such as a digital video disk; it may also be a semiconductor medium, such as a solid-state hard disk.

In each embodiment of the present application, if there is no special explanation and logical conflict, the terms and/or descriptions between different embodiments are consistent and can be referred to each other, and the technical features in different embodiments are based on their inherent Logical relationships can be combined to form new embodiments.

In this application, "at least one" means one or more, and "multiple" means two or more. "And/or" describes the association relationship of associated objects, indicating that there can be three types of relationships, for example, A and/or B, which can mean: A exists alone, A and B exist at the same time, and B exists alone, where A, B can be singular or plural. In the text description of this application, the character "/" generally indicates that the contextual objects are an "or" relationship; in the formulas of this application, the character "/" indicates that the contextual objects are a "division" Relationship.

It can be understood that the various numbers involved in the embodiments of the present application are only for convenience of description, and are not used to limit the scope of the embodiments of the present application. The size of the serial numbers of the above-mentioned processes does not mean the order of execution, and the execution order of each process should be determined by its functions and internal logic.

Claims

An end-to-end D2D communication method, characterized in that the method comprises:

receiving a first transfer UE information list sent by a first user equipment UE; wherein, the first transfer UE information list includes path information of a first communication path between the first UE and a second UE, and the second UE is the target UE;

Receive first heartbeat information sent by the first UE, where the first heartbeat information includes the device identifier of the first UE and a first version number, and the first version number is used to confirm whether the first transit UE information list is the updated transit UE information list;

When it is confirmed based on the first version number that the first relay UE information list is the updated relay UE information list, sending first unicast information based on the first relay UE information list.
The method according to claim 1, further comprising:

When it is confirmed based on the first version number that the first transfer UE information list is not the updated transfer UE information list, send a first request to the first UE, where the first request is used to indicate the first transfer UE information list A UE sends the updated transfer UE information list;

receiving the updated transfer UE information list sent by the first UE, where the updated transfer UE information list includes path information of a second communication path between the first UE and the third UE;

Sending the first unicast information based on the updated relay UE information list.
The method according to claim 2, wherein the sending the first request to the first UE comprises;

Sending a first request to the first UE when the updated transfer UE information list has not been received within a first time after receiving the first heartbeat information.
The method according to any one of claims 1-3, wherein the first relay UE information list includes a second version number;

The method further includes: comparing the first version number and the second version number to confirm that the first relay UE information list is the updated relay UE information list based on the first version number.
The method according to any one of claims 1-3, wherein before receiving the first transfer UE information list sent by the first UE, the method further comprises:

receiving a second heartbeat message sent by the first UE; the second heartbeat message includes the device identifier and a third version number of the first UE;

comparing the first version number with the third version number to confirm that the first relay UE information list is the updated relay UE information list based on the first version number.
The method according to any one of claims 1-5, wherein after receiving the first heartbeat information sent by the first UE, the method further comprises:

If the updated heartbeat message sent by the first UE is not received within the second time, modify the communication status of the first UE from on-net to off-net, or use the first UE as a next-hop UE The communication status in the communication path of the network is changed from on-net to off-net.
The method according to claim 5, wherein after receiving the second heartbeat message sent by the first UE and before receiving the first transit UE information list sent by the first UE, the method Also includes:

Before receiving the second heartbeat message, the first transit UE information list is not received, and at a third time after receiving the second heartbeat message, the first transit UE information list is not received, Sending a second request to the first UE, where the second request is used to instruct the first UE to send the first transfer UE information list.
The method according to any one of claims 1-7, wherein the first transfer UE information list further includes

The communication status of the second UE, the number of transit hops for data transmission in the first communication path, and the UEID of the next-hop UE of the first UE in the first communication path.
The method according to any one of claims 1-8, wherein the first relay UE information list further includes a networking identifier of the second UE.
The method according to any one of claims 1-9, wherein the first unicast message includes service data, UEID of the source user equipment, target UEID, and transit UEID.
A communication device, characterized by comprising:

The receiving unit is configured to receive a first transfer UE information list sent by the first UE; wherein the first transfer UE information list includes path information of a first communication path between the first UE and the second UE, and the The second UE is a target UE;

The receiving unit is further configured to receive first heartbeat information sent by the first UE, the first heartbeat information includes the device identifier of the first UE and a first version number, and the first version number is used to confirm the Whether the first transfer UE information list is an updated transfer UE information list;

A sending unit, configured to send first unicast information based on the first transfer UE information list when it is confirmed based on the first version number that the first transfer UE information list is the updated transfer UE information list.
The communication device according to claim 11, wherein the sending unit is further configured to, when it is confirmed based on the first version number that the first transfer UE information list is not the updated transfer UE information list, sending a first request to the first UE, where the first request is used to instruct the first UE to send the updated transfer UE information list;

The receiving unit is further configured to receive the updated transfer UE information list sent by the first UE, where the updated transfer UE information list includes a path of a second communication path between the first UE and the third UE information;

The sending unit is further configured to send the first unicast information based on the updated relay UE information list.
The communication device according to claim 12, wherein the sending unit is further configured to receive the updated transfer UE information list when the first time is reached after receiving the first heartbeat information, Send a first request to the first UE.
The communication device according to any one of claims 11-13, wherein the first transfer UE information list includes a second version number; the communication device further includes a processing unit;

Wherein, the processing unit is configured to compare the first version number and the second version number, so as to confirm that the first transfer UE information list is the updated transfer UE information list based on the first version number.
The communication device according to any one of claims 11-13, wherein the receiving unit is further configured to receive a second heartbeat message sent by the first UE; the second heartbeat message includes the first - UE's device identification and third version number;

The processing unit is further configured to compare the first version number with the third version number, so as to confirm that the first transfer UE information list is the updated transfer UE information list based on the first version number.
The communication device according to any one of claims 11-15, wherein the processing unit is further configured to send the second heartbeat message if the updated heartbeat message sent by the first UE is not received within a second time. The communication state of a UE is changed from on-net to off-net, or the communication state on the communication path in which the first UE is used as the next-hop UE is changed from on-net to off-net.
The communication device according to claim 15, wherein the processing unit is further configured to fail to receive the first transit UE information list before receiving the second heartbeat message, and to receive the second At a third time after the heartbeat message, if the first transit UE information list is not received, send a second request to the first UE, where the second request is used to instruct the first UE to send the first Transfer UE information list.
The communication device according to any one of claims 11-17, wherein the first transit UE information list further includes the communication status of the second UE, and the transit hop for data transmission in the first communication path. number, and the equipment identifier UEID of the next-hop UE of the first UE in the first communication path.
The communication device according to any one of claims 11-18, wherein the first relay UE information list further includes a networking identifier of the second UE.
The communication device according to any one of claims 11-19, wherein the first unicast message includes service data, a UEID of a source user equipment, a target UEID, and a transfer UEID.
A chip or chip system, characterized in that it includes a processing circuit and an interface circuit, the interface circuit is used to receive code instructions and transmit them to the processing circuit, and the processing circuit is used to run the code instructions to execute the The method described in any one of claims 1-10.
A computer-readable storage medium, where instructions are stored in the computer-readable storage medium, and when the instructions are run on a communication device, the communication device is made to execute the method according to any one of claims 1-10 .
A computer program product, characterized in that, when the computer program product is executed by a communication device, the communication device is made to execute the method according to any one of claims 1-10.