A path determination method, terminal and communication system

Abstract

The disclosure provides a path determination method, a terminal and a communication system, and relates to the technical field of communication. The path determination method is executed by a first terminal, and includes: receiving a first discovery request message from a second terminal; judging whether information of a previous hop node of the first terminal in a path from a source terminal to a target terminal has been stored according to information of the source terminal and information of the target terminal; in the case that the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has not been stored, determining and storing the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal according to the first discovery request message; and sending a second discovery request message to a third terminal. Through the above method, a communication path for communication between two terminals through a single or multiple relay terminals can be efficiently and reliably established.

Description

Technical Field

[0001] This disclosure relates to the field of communication technology, and in particular to a path determination method, a terminal, and a communication system. Background Technology

[0002] In the 3rd Generation Partnership Project (3GPP) standard, two User Equipment (UEs) supporting Proximity Service (ProSe) can establish a direct communication connection via a sidelink (or PC5 interface). Furthermore, the 3GPP standard also supports sidelink-based communication connections between two UEs via a relay UE, and allows a single UE to connect to the mobile network via a relay UE. This expands network coverage and reduces network investment.

[0003] There may be multiple terminals with relay capabilities within a network. When two terminals supporting proximity services need to communicate, they can do so by establishing a multi-hop communication path through at least one relay terminal. By establishing multi-hop communication paths, deep coverage of communication services can be achieved, reducing reliance on wireless base station deployment and lowering network deployment costs. Summary of the Invention

[0004] This disclosure provides a path determination method, a terminal, and a communication system.

[0005] According to a first aspect of this disclosure, a path determination method is proposed, executed by a first terminal, comprising: receiving a first discovery request message from a second terminal, the first discovery request message including information of a source terminal and information of a target terminal, wherein the first terminal is a relay terminal and the second terminal is either a source terminal or a relay terminal; determining, based on the information of the source terminal and the information of the target terminal, whether information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored; if the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has not been stored, determining and storing the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal based on the first discovery request message; and sending a second discovery request message to a third terminal, the second discovery request message including information of the source terminal, information of the first terminal, and information of the target terminal, for assisting the third terminal in determining the information of the previous hop node of the third terminal in the path from the source terminal to the target terminal, wherein the third terminal is either the target terminal or a relay terminal.

[0006] In some embodiments, the path determination method further includes: discarding the first discovery request message if information about the previous hop node of the first terminal in the path from the source terminal to the target terminal has already been stored.

[0007] In some embodiments, the path determination method further includes: upon receiving a first discovery response message within a first duration, determining and storing information about the next-hop node of the first terminal in the path from the source terminal to the target terminal based on the first discovery response message, wherein the first discovery response message includes information about the source terminal and information about the target terminal, and the first duration is counted from the time the information about the previous-hop node of the first terminal in the path from the source terminal to the target terminal is determined; and sending a second discovery response message to the previous-hop node of the first terminal in the path from the source terminal to the target terminal, wherein the second discovery response message includes at least one of a relay service code supported by the source terminal and a second hop count, information about the source terminal, information about the first terminal, and information about the target terminal, wherein the second hop count is the total number of hops in the path from the source terminal to the target terminal.

[0008] In some embodiments, the path determination method further includes: if no first discovery response message is received within a first time period, deleting the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal.

[0009] In some embodiments, the path determination method further includes: upon receiving a first path establishment request within a second duration, establishing a direct communication path with the previous hop node of the first terminal, wherein the second duration is counted from the time the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal and the information of the next hop node of the first terminal in the path from the source terminal to the target terminal are determined; and sending a second path establishment request to the next hop node of the first terminal.

[0010] In some embodiments, the path determination method further includes: if no first path establishment request is received from the previous hop node of the first terminal within a second time period, deleting the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal, and the information of the next hop node of the first terminal in the path from the source terminal to the target terminal.

[0011] In some embodiments, the first discovery request message further includes at least one of a relay service code supported by the source terminal and a first hop count, and, if the second terminal is a relay terminal, the first discovery request message further includes information about the second terminal, wherein the first hop count is the cumulative hop count starting from the source terminal, and the information about the second terminal includes the identifier of the second terminal and the identifier of the Layer 2 link used by the second terminal for direct communication.

[0012] In some embodiments, determining and storing the information of the previous hop node in the path from the source terminal to the target terminal according to the first discovery request message includes: determining and storing the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal according to at least one of the time of receiving the first discovery request message, the first hop count, the signal strength of the first discovery request message, and the multi-hop cumulative signal strength.

[0013] In some embodiments, the information of the source terminal in the first discovery request message includes at least one of the identifier of the source terminal and the layer 2 link identifier used by the source terminal for direct communication, and the information of the target terminal in the first discovery request message includes the identifier of the target terminal or the identifier of the capability that the target terminal needs to support.

[0014] In some embodiments, the first discovery response message may further include at least one of a relay service code supported by the source terminal and a second hop count, wherein the second hop count is the total number of hops of the path from the source terminal to the target terminal.

[0015] In some embodiments, the source terminal information in the first discovery response message includes the identifier of the source terminal, and the target terminal information in the first discovery response message includes the identifier of the target terminal and the Layer 2 link identifier used by the target terminal for direct communication.

[0016] According to a second aspect of this disclosure, a path determination method is proposed, executed by a third terminal, comprising: receiving a second discovery request message from a first terminal, the second discovery request message including information of a source terminal, information of the first terminal, and information of a target terminal, wherein the first terminal is a relay terminal; if the first terminal determines itself to be the target terminal, determining, based on the second discovery request message, whether to use a path containing the first terminal as the path from the source terminal to the target terminal; if the first terminal determines to use a path containing the first terminal as the path from the source terminal to the target terminal, sending a first discovery response message to the first terminal, the first discovery response message being used to assist the first terminal in determining information of the next-hop node of the first terminal in the path from the source terminal to the target terminal.

[0017] In some embodiments, determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal according to the second discovery request message includes: determining whether the path information from the source terminal to the target terminal has been stored based on the information of the source terminal and the information of the target terminal; if the path information from the source terminal to the target terminal has not been stored, determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal according to the second discovery request message.

[0018] In some embodiments, determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal based on the second discovery request message further includes: discarding the second discovery request message if the path information from the source terminal to the target terminal has already been stored.

[0019] In some embodiments, the path determination method further includes: if a second path establishment request is received from the first terminal within a third time period, establishing a direct communication path with the first terminal, wherein the third time period is started after the path information from the source terminal to the target terminal is determined by the third terminal.

[0020] In some embodiments, the path determination method further includes: deleting the path information from the source terminal to the target terminal if no second path establishment request is received from the first terminal within a third time period.

[0021] In some embodiments, the second discovery request message further includes at least one of a third hop count and a relay service code supported by the source terminal. The step of determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal based on the second discovery request message includes: determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal based on at least one of the time of receiving the second discovery request message, the third hop count, the signal strength of the second discovery request message, and the multi-hop cumulative signal strength. The third hop count is the number of hops accumulated from the source terminal.

[0022] According to a third aspect of this disclosure, a first terminal is provided, comprising: a receiving module configured to receive a first discovery request message from a second terminal, the first discovery request message including information of a source terminal and information of a target terminal, the first terminal being a relay terminal and the second terminal being the source terminal or the relay terminal; a judging module configured to judge, based on the information of the source terminal and the information of the target terminal, whether information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored; a determining module configured to, if the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has not been stored, determine and store information of the previous hop node of the first terminal in the path from the source terminal to the target terminal based on the first discovery request message; and a sending module configured to send a second discovery request message to a third terminal, the second discovery request message including information of the source terminal, information of the first terminal, and information of the target terminal, for assisting the third terminal in determining information of the previous hop node of the third terminal in the path from the source terminal to the target terminal, the third terminal being the target terminal or the relay terminal.

[0023] According to a fourth aspect of this disclosure, a third terminal is proposed, comprising: a receiving module configured to receive a second discovery request message from a first terminal, the second discovery request message including information of a source terminal, information of the first terminal, and information of a target terminal, wherein the first terminal is a relay terminal; a judging module configured to, if the third terminal is determined to be the target terminal, determine, based on the second discovery request message, whether to use a path containing the first terminal as a path from the source terminal to the target terminal; and a sending module configured to, if the path containing the first terminal is determined to be a path from the source terminal to the target terminal, send a first discovery response message to the first terminal, the first discovery response message being used to assist the first terminal in determining information of the next-hop node in the path from the source terminal to the target terminal.

[0024] According to a fifth aspect of this disclosure, a communication system is proposed, comprising: a first terminal configured to: receive a first discovery request message from a second terminal, wherein the first terminal is a relay terminal and the second terminal is a source terminal or a relay terminal, the first discovery request message including information of the source terminal and information of a target terminal; determine, based on the information of the source terminal and the information of the target terminal, whether information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored; if the information of the previous hop node in the path from the source terminal to the target terminal has not been stored, determine and store the information of the previous hop node in the path from the source terminal to the target terminal based on the first discovery request message; and send a second discovery request message, the second discovery request message including information of the source terminal, information of the first terminal, and information of the target terminal; and a third terminal configured to: receive the second discovery request message from the first terminal; and, if it determines that it belongs to the target terminal, determine, based on the second discovery request message, whether to use the path containing the first terminal as the path from the source terminal to the target terminal.

[0025] In some embodiments, the third terminal is further configured to: when determining that the path containing the first terminal is the path from the source terminal to the target terminal, send a first discovery response message to the first terminal, the first discovery response message including information of the source terminal and information of the target terminal, for assisting the first terminal in determining the information of the next-hop node in the path from the source terminal to the target terminal.

[0026] In some embodiments, the first terminal is further configured to: upon receiving a first discovery response message within a first duration, determine and store information of the next-hop node in the path from the source terminal to the target terminal based on the first discovery response message; and send a second discovery response message to the previous-hop node in the path from the source terminal to the target terminal determined thereto, the second discovery response message including at least one of a relay service code supported by the source terminal and a second hop number, information of the source terminal, information of the first terminal, and information of the target terminal, the second hop number being the total number of hops in the path from the source terminal to the target terminal.

[0027] In some embodiments, the communication system further includes the second terminal, wherein, when the second terminal is the source terminal, the second terminal is configured to: upon receiving a second discovery response message from the first terminal, send a first path establishment request to the first terminal to establish a direct communication path with the first terminal.

[0028] In some embodiments, the communication system further includes the second terminal, wherein, when the second terminal is the source terminal, the second terminal is further configured to: upon receiving a plurality of discovery response messages including the second discovery response message, determine, based on the plurality of discovery response messages, whether to use the first terminal as the next-hop node of the second terminal in the path from the source terminal to the target terminal; and if it is determined that the first terminal is used as the next-hop node of the second terminal in the path from the source terminal to the target terminal, send a first path establishment request to the first terminal to establish a direct communication path with the first terminal.

[0029] In some embodiments, determining whether to use the first terminal as the next-hop node of the second terminal in the path from the source terminal to the target terminal based on the plurality of discovery response messages includes: determining whether to use the first terminal as the next-hop node of the second terminal in the path from the source terminal to the target terminal based on at least one of the time of receiving the plurality of discovery response messages, the number of hops carried by the plurality of discovery response messages, the signal strength of the plurality of discovery response messages, and the multi-hop cumulative signal strength corresponding to each of the plurality of discovery response messages.

[0030] According to a sixth aspect of this disclosure, an electronic device is provided, comprising: a memory; and a processor coupled to the memory, the processor being configured to execute the path determination method as described above based on instructions stored in the memory.

[0031] According to the seventh aspect of this disclosure, a computer-readable storage medium is provided that stores computer program instructions thereon, which, when executed by a processor, implement the path determination method as described above.

[0032] Other features and advantages of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0033] The accompanying drawings, which form part of this specification, illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0034] This disclosure can be more clearly understood with reference to the accompanying drawings and the following detailed description.

[0035] Figure 1 This is a flowchart illustrating a path determination method according to some embodiments of the present disclosure.

[0036] Figure 2 This is a flowchart illustrating a path determination method according to other embodiments of the present disclosure.

[0037] Figure 3This is a flowchart illustrating a path determination method according to some embodiments of the present disclosure.

[0038] Figure 4 This is a flowchart illustrating a path determination method according to some embodiments of the present disclosure.

[0039] Figure 5 This is a schematic diagram illustrating the principle of a path determination method according to some embodiments of the present disclosure.

[0040] Figure 6 This is a schematic diagram illustrating the propagation path of a discovery message according to some embodiments of this disclosure.

[0041] Figure 7 This is a flowchart illustrating a path determination method according to some embodiments of the present disclosure.

[0042] Figure 8 This is a schematic diagram of the structure of a first terminal according to some embodiments of the present disclosure.

[0043] Figure 9 This is a schematic diagram of the structure of a third terminal according to some embodiments of the present disclosure.

[0044] Figure 10 This is a schematic diagram of the structure of a communication system according to some embodiments of the present disclosure.

[0045] Figure 11 This is a schematic diagram of the structure of an electronic device according to some embodiments of the present disclosure.

[0046] Figure 12 This is a schematic diagram of the structure of a computer system according to some embodiments of the present disclosure. Detailed Implementation

[0047] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0048] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0049] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0050] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0051] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0052] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0053] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0054] In multi-hop communication scenarios involving proximity services, a key issue is how to efficiently and reliably establish a communication path between two terminals via single-hop or multi-hop relay terminals. Currently, no corresponding solutions are provided in relevant technologies.

[0055] In view of this, this disclosure provides a path determination method, a terminal, and a communication system that can efficiently and reliably establish a communication path for two terminals to communicate through one or more relay terminals.

[0056] Figure 1 This is a flowchart illustrating a path determination method according to some embodiments of the present disclosure. Figure 1 The path determination method shown is executed by the first terminal, which is a relay terminal. For example... Figure 1 As shown, the path determination method in some embodiments of this disclosure includes steps S110 to S130.

[0057] In step S110, a first discovery request message is received from the second terminal.

[0058] In some embodiments, the second terminal is a relay terminal or a source terminal. A relay terminal is a terminal that acts as a relay; a source terminal is the initiator of the discovery process, in other words, the terminal that first sends a discovery request message in the discovery process.

[0059] In some embodiments, the second terminal broadcasts a first discovery request message. In addition to receiving the first discovery request message from the second terminal, the first terminal may also receive discovery request messages from other terminals.

[0060] In some embodiments, the first discovery request message includes information about the source terminal and information about the target terminal.

[0061] For example, the information of the source terminal in the first discovery request message includes, but is not limited to, at least one of the following: the identifier of the source terminal and the identifier of the Layer 2 link used by the source terminal for direct communication.

[0062] For example, the information about the target terminal in the first discovery request message includes, but is not limited to, the identifier of the target terminal, or the identifier of the capabilities that the target terminal needs to support. Among them, the identifier of the capabilities that the target terminal needs to support includes, but is not limited to, the identifier of the network connectivity capabilities that the target terminal needs to support (such as supporting a certain slicing, a certain DNN, supporting Layer 2 communication, etc.) and the identifier of the service capabilities that the target terminal needs to support (such as supporting a certain proximity service).

[0063] In some implementations, when the target terminal is a predetermined designated terminal, the first discovery request message carries the identifier of the target terminal; when the target terminal is a terminal to be determined, the first discovery request message carries the identifier of the capabilities that the target terminal needs to support.

[0064] In some embodiments, the first discovery request message includes, in addition to the information of the source terminal and the target terminal, at least one of the following: a first hop count, a relay service code (RSC) supported by the source terminal, and information of the second terminal.

[0065] The first hop count is the cumulative hop count starting from the source terminal. For example, in the discovery request message sent by the source terminal, the first hop count is set to 0; in the discovery request message sent by the relay terminal, the first hop count is set to l1+1. Here, l1 is the hop count carried in the discovery request message sent by the previous hop node determined by the relay terminal.

[0066] For example, the information about the second terminal in the first discovery request message includes the identifier of the second terminal and the identifier of the Layer 2 link used by the second terminal for direct communication.

[0067] In step S120, the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal is determined and stored.

[0068] In some embodiments, step S120 includes: determining, based on the information of the source terminal and the information of the target terminal, whether the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored; if the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has not been stored, determining and storing the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal based on the first discovery request message.

[0069] For example, the first terminal queries the storage module based on the information of the source terminal and the target terminal, and determines whether the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored based on the query result.

[0070] In some embodiments, determining and storing the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal according to the first discovery request message includes: determining the previous hop node of the first terminal in the path from the source terminal to the target terminal according to at least one of the time of receiving the first discovery request message, the number of first hops carried in the first discovery request message, the signal strength of the first discovery request message, and the cumulative signal strength of multiple hops, and storing the information of the previous hop node.

[0071] For example, if the first terminal determines that the first terminal received the first discovery request message from the second terminal earliest among the multiple discovery request messages it has received, then the second terminal will be used as the previous hop node of the first terminal in the path from the source terminal to the target terminal.

[0072] For example, if the first terminal determines that among the multiple discovery request messages it has received, the first terminal has the smallest first hop number carried in the first discovery request message of the second terminal, then the first terminal will be used as the previous hop node of the first terminal in the path from the source terminal to the target terminal.

[0073] For example, if the first terminal determines that the signal strength of the first discovery request message from the second terminal is the strongest among the multiple discovery request messages it has received, then the first terminal will be used as the previous hop node of the first terminal in the path from the source terminal to the target terminal.

[0074] For example, the first terminal combines two or more of the following factors to determine the previous hop node of the first terminal in the path from the source terminal to the target terminal: the time when the first discovery request message is received, the number of first hops carried in the first discovery request message, the signal strength of the first discovery request message, and the cumulative signal strength of the multi-hop message.

[0075] In some embodiments, determining and storing the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal according to the first discovery request message includes: the first terminal determining whether its supported RSC is consistent with the RSC supported by the source terminal carried in the first discovery request message; if the two RSCs are consistent, determining the previous hop node of the first terminal in the path from the source terminal to the target terminal according to at least one of the time of receiving the first discovery request message, the number of first hops carried in the first discovery request message, the signal strength of the first discovery request message, and the multi-hop cumulative signal strength, and storing the information of the previous hop node; if the two RSCs are inconsistent, discarding the first discovery request message.

[0076] In some embodiments, the path determination method further includes: discarding the first discovery request message if information about the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored. In some embodiments, discarding the first discovery request message means ignoring the first discovery request message, i.e., not performing subsequent processing based on the first discovery request message; in other embodiments, discarding the first discovery request message means ignoring and deleting the first discovery request message.

[0077] In this embodiment of the disclosure, by first determining whether the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored, and then executing step S120 if the determination result is negative, not only can the resource overhead caused by repeatedly executing the previous node determination operation in the path determination process be reduced, but also the problem of inconsistent previous hop nodes determined by the first terminal multiple times due to repeated execution of the previous node determination operation, resulting in inconsistent discovery request messages broadcast by the first terminal multiple times, ultimately leading to path establishment failure, is effectively alleviated, thereby improving the reliability and efficiency of the path determination process.

[0078] In step S130, a second discovery request message is sent to the third terminal.

[0079] In some embodiments, the third terminal is a target terminal or a relay terminal. The target terminal is the terminal that the source terminal wants to connect to.

[0080] In some embodiments, the first terminal broadcasts a second discovery request message. Besides the third terminal receiving the second discovery request message, other terminals may also receive it.

[0081] When the third terminal is a relay terminal, it performs a similar process to the first terminal: determining the previous hop node on the path from the source terminal to the target terminal based on the received discovery request message, and broadcasting its own discovery request message. When the third terminal is the target terminal, it determines the previous hop node on the path from the source terminal to the target terminal based on the received discovery request message, and sends a discovery response message to the determined previous hop node.

[0082] In some embodiments, the second discovery request message includes information about the source terminal, information about the first terminal, and information about the target terminal.

[0083] For example, the information of the source terminal in the second discovery request message includes, but is not limited to, at least one of the following: the identifier of the source terminal and the identifier of the Layer 2 link used by the source terminal for direct communication.

[0084] For example, the information of the first terminal in the second discovery request message includes, but is not limited to, at least one of the identifier of the first terminal and the layer 2 link identifier used by the first terminal for direct communication.

[0085] For example, the information of the target terminal in the second discovery request message includes, but is not limited to, the identifier of the target terminal or the identifier of the capabilities that the target terminal needs to support.

[0086] In some embodiments, the second discovery request message includes, in addition to the information of the source terminal, the information of the first terminal, and the information of the target terminal, at least one of a third hop count and a relay service code supported by the source terminal. The third hop count is the cumulative hop count starting from the source terminal. For example, the third hop count in the second discovery request message is l2+1. Here, l2 is the hop count carried in the discovery request message sent by the previous hop node determined by the first terminal.

[0087] In this embodiment, the above steps design a discovery request process for multi-hop communication paths in proximity services, thereby efficiently and reliably determining the communication path between the source terminal and the target terminal via one or more relay terminals. This allows for multi-hop communication without relying on the network, utilizing terminal resources (including processing power and spectrum) to achieve the communication purpose, and saving network deployment costs.

[0088] Figure 2 This is a flowchart illustrating a path determination method according to other embodiments of the present disclosure. Figure 2 The path determination method shown is executed by the first terminal, which is a relay terminal. For example... Figure 2 As shown, the path determination method in some other embodiments of this disclosure includes steps S210 to S280. Embodiments of this disclosure and... Figure 1 The main difference in the illustrated embodiment is the addition of steps S240 to S280. Therefore, steps S240 to S280 will be described below.

[0089] In step S210, a first discovery request message is received from the second terminal.

[0090] In some embodiments, the second terminal broadcasts a first discovery request message. The second terminal is either a source terminal or a relay terminal.

[0091] In some embodiments, the discovery request message is broadcast outwards. In addition to receiving the first discovery request message from the second terminal, the first terminal may also receive discovery request messages from other terminals.

[0092] In step S220, the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal is determined and stored.

[0093] In step S230, a second discovery request message is sent to the third terminal.

[0094] In some embodiments, the first terminal broadcasts a second discovery request message. The third terminal is either a relay terminal or a target terminal.

[0095] In the discovery sub-process initiated by the source terminal, each terminal participating in the discovery sub-process, excluding the source terminal, is responsible for determining the previous hop node preceding itself on the path from the source terminal to the target terminal. This previous hop node preceding itself on the path from the source terminal to the target terminal can also be considered the next hop node following itself on the path from the target terminal to the source terminal. Therefore, after the target terminal determines the previous hop node preceding itself on the path from the source terminal to the target terminal, it determines a path from the target terminal to the source terminal.

[0096] In step S240, a first discovery response message is received.

[0097] In some embodiments, the first discovery response message includes information about the source terminal and information about the target terminal.

[0098] For example, the source terminal information in the first discovery response message includes the identifier of the source terminal.

[0099] For example, the information of the target terminal in the first discovery response message includes the identifier of the target terminal and the identifier of the Layer 2 link through which the target terminal conducts direct communication.

[0100] In some embodiments, the first discovery response message includes, in addition to the information of the source terminal and the target terminal, at least one of the following: the relay service code supported by the source terminal and a second hop count. The second hop count is the total number of hops in the path from the source terminal to the target terminal. For example, in the discovery response message sent by the target terminal, the second hop count is set to the hop count of the previous hop node preceding the target terminal in the path determined by the target terminal, plus 1.

[0101] In some embodiments, when the sender of the first discovery response message is a relay terminal, the first discovery response message includes, in addition to the information of the source terminal and the target terminal, the information of the sending terminal of the first discovery response message, such as the identifier of the sending terminal of the first discovery response message and the identifier of the Layer 2 link through which the sending terminal conducts direct communication.

[0102] In some embodiments, step S240 includes receiving a first discovery response message within a first duration. In some embodiments, the first duration is the time taken after determining the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal. Specifically, the first terminal may start a first timer to count the first duration after determining the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal.

[0103] In some embodiments, the path determination method further includes: if no first discovery response message is received within a first time period, deleting the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal.

[0104] In this embodiment of the disclosure, by deleting the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal that the first terminal has stored after not receiving the first discovery response message within a first time period, the resource overhead caused by the relay terminal located outside the path selected by the target terminal continuously storing node information can be reduced.

[0105] In step S250, the information of the next-hop node of the first terminal in the path from the source terminal to the target terminal is determined and stored.

[0106] In some embodiments, step S250 includes: if a first discovery response message is received within a first time period, determining and storing information about the next-hop node of the first terminal in the path from the source terminal to the target terminal based on the first discovery response message.

[0107] For example, if a first discovery response message is received from a third terminal within the first time period, the information of the third terminal is used as the information of the next-hop node of the first terminal in the path from the source terminal to the target terminal, and the information is stored.

[0108] In step S260, a second discovery response message is sent to the previous hop node of the first terminal.

[0109] In some embodiments, the first terminal sends a second discovery response message via unicast to the previous hop node of the first terminal in the path from the source terminal to the target terminal.

[0110] After each terminal completes the discovery sub-process, the target terminal initiates the discovery response sub-process. In this sub-process, each participating relay terminal is responsible for determining the next-hop node following itself on the path from the source terminal to the target terminal. Once the source terminal determines the next-hop node on the path from itself to the target terminal, it then establishes a path from the source terminal to the target terminal.

[0111] In some embodiments, the second discovery response message includes information about the source terminal, information about the first terminal, and information about the target terminal.

[0112] For example, the source terminal information in the second discovery response message includes the identifier of the source terminal.

[0113] For example, the information of the first terminal in the second discovery response message includes the identifier of the first terminal and the identifier of the Layer 2 link through which the first terminal conducts direct communication.

[0114] For example, the information of the target terminal in the second discovery response message includes the identifier of the target terminal and the identifier of the Layer 2 link through which the target terminal conducts direct communication.

[0115] In some embodiments, the second discovery response message includes, in addition to the information of the source terminal, the information of the first terminal, and the information of the target terminal, at least one of the following: the relay service code supported by the source terminal and the second hop count. For example, the second hop count is the total number of hops on the path from the source terminal to the target terminal. In this example, the second hop count in the second discovery response message is the same as the second hop count in the first discovery response message.

[0116] In step S270, a first path establishment request is received from the previous hop node of the first terminal.

[0117] In some embodiments, the first path establishment request is sent via unicast.

[0118] In some embodiments, the first path establishment request includes information about the source terminal, information about the first terminal, and information about the target terminal. For example, the information about the first terminal in the first path establishment request includes the identifier of the first terminal and the identifier of the Layer 2 link for direct communication between the first terminal and the target terminal.

[0119] In some embodiments, step S270 includes: receiving a first path establishment request from the previous hop node of the first terminal within a second duration. The second duration is calculated after determining the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal, and the information of the next hop node of the first terminal in the path from the source terminal to the target terminal. Specifically, the first terminal may start a second timer to count the second duration after determining the information of the next hop node of the first terminal in the path from the source terminal to the target terminal.

[0120] In some embodiments, the path determination method further includes: if no first path establishment request is received within a second time period, deleting the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal, and the information of the next hop node of the first terminal in the path from the source terminal to the target terminal.

[0121] In this embodiment of the disclosure, by deleting the information of the previous hop node and the next hop node of the first terminal in the path from the source terminal to the target terminal that the first terminal has stored after not receiving the first path establishment request within the second time period, the resource overhead caused by the relay terminal located outside the finally selected path continuously storing node information can be reduced.

[0122] In step S280, a direct communication path is established with the previous hop node of the first terminal.

[0123] In some embodiments, after receiving a first path establishment request from the previous hop node of the first terminal within a second time period, the first terminal establishes a direct communication path with the previous hop node of the first terminal.

[0124] In step S290, a second path establishment request is sent to the next-hop node of the first terminal.

[0125] In some embodiments, the second path establishment request is sent in a unicast manner to the next-hop node of the first terminal on the path from the source terminal to the target terminal.

[0126] In some embodiments, the second path establishment request includes information about the source terminal, information about the next-hop node of the first terminal, and information about the target terminal. For example, the information about the next-hop node of the first terminal in the second path establishment request includes the identifier of the next-hop node of the first terminal and the identifier of the Layer 2 link through which the next-hop node of the first terminal establishes direct communication.

[0127] After completing the discovery response sub-process, the source terminal initiates the connection establishment sub-process. In the connection establishment sub-process initiated by the source terminal, each relay terminal sequentially receives the path establishment request from the previous hop node, establishes a connection with the previous hop node, and then sends a path establishment request to the next hop node until the communication connection for the entire path is established.

[0128] In this embodiment, the above steps design a discovery request, discovery response, and connection establishment process for multi-hop communication paths in proximity services, thereby efficiently and reliably determining the communication path between the source terminal and the target terminal via one or more relay terminals. This allows for multi-hop communication without relying on the network, utilizing terminal resources (including processing power and spectrum) to achieve the communication purpose, and saving network deployment costs.

[0129] Figure 3 This is a flowchart illustrating a method for determining a path according to some embodiments of the present disclosure. Figure 3 The path determination method shown is executed by a third terminal, which can be either a relay terminal or a target terminal. For example... Figure 3As shown, the path determination method in some embodiments of this disclosure includes steps S310 to S330.

[0130] In step S310, a second discovery request message is received from the first terminal.

[0131] The first terminal is a relay terminal.

[0132] In some embodiments, the second discovery request message includes information about the source terminal, information about the first terminal, and information about the target terminal.

[0133] For example, the information of the source terminal in the second discovery request message includes at least one of the source terminal's identifier and the Layer 2 link identifier for which the source terminal conducts direct communication.

[0134] For example, the information of the first terminal in the second discovery request message includes at least one of the identifier of the first terminal and the identifier of the Layer 2 link through which the first terminal conducts direct communication.

[0135] For example, the information about the target terminal in the second discovery request message may include the identifier of the target terminal or the capability identifier of the target terminal.

[0136] In some embodiments, the second discovery request message includes, in addition to the information of the source terminal, the information of the first terminal, and the information of the target terminal, at least one of a third hop count and a relay service code supported by the source terminal. The third hop count is the cumulative hop count starting from the source terminal.

[0137] In step S320, if it is determined that it is the target terminal, it is determined whether to use the path containing the first terminal as the path from the source terminal to the target terminal according to the second discovery request message.

[0138] In some embodiments, the third terminal compares its own identifier with the identifier of the target terminal carried in the second discovery request message. If the identifier of the third terminal matches the identifier of the target terminal carried in the second discovery request message, it confirms that it is the target terminal; otherwise, it confirms that it is not the target terminal.

[0139] In some embodiments, the third terminal compares the capability identifier it supports with the capability identifier that the target terminal needs to support, carried in the second discovery request message. If the capability identifier that the third terminal supports matches the capability identifier that the target terminal needs to support, it confirms that it is the target terminal; otherwise, it confirms that it is not the target terminal.

[0140] In some embodiments, determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal according to the second discovery request message includes: determining whether the path information from the source terminal to the target terminal has been stored based on the information of the source terminal and the information of the target terminal; if the path information from the source terminal to the target terminal has not been stored, determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal according to the second discovery request message.

[0141] In some implementations, the path information from the source terminal to the target terminal stored in the third terminal is the information of the previous hop node on the path from the source terminal to the target terminal, located before the third terminal.

[0142] In some embodiments, when the third terminal is the target terminal, determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal according to the second discovery request message includes: determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal based on at least one of the time of receiving the second discovery request message, the third hop count, the signal strength of the second discovery request message, and the multi-hop cumulative signal strength.

[0143] For example, if the third terminal determines that the second discovery request message of the first terminal was received earliest among the multiple discovery request messages it has received, it will use the path containing the first terminal as the path from the source terminal to the target terminal.

[0144] For example, if the third terminal determines that among the multiple discovery request messages it receives, the third terminal's second discovery request message carries the smallest third hop count, then the path containing the first terminal will be used as the path from the source terminal to the target terminal.

[0145] For example, if the third terminal determines that the signal strength of the second discovery request message from the first terminal is the strongest among the multiple discovery request messages it has received, it will use the path containing the first terminal as the path from the source terminal to the target terminal.

[0146] For example, the third terminal may combine two or more of the following factors to determine whether to use the path containing the first terminal as the path from the source terminal to the target terminal: the time when the second discovery request message is received, the number of third hops carried in the second discovery request message, the signal strength of the second discovery request message, and the cumulative signal strength of the multi-hops.

[0147] In some embodiments, the path determination method further includes: discarding the second discovery request message if the third terminal has already stored path information from the source terminal to the target terminal.

[0148] In some embodiments, the path determination method further includes: if the third terminal confirms that it is not the target terminal, comparing its supported RSC with the RSC supported by the source terminal carried in the second discovery request message. If the two RSCs match, the third terminal, as a relay terminal, performs a processing procedure similar to that of the first terminal; if the two RSCs do not match, the third terminal discards the second discovery request message.

[0149] In step S330, if it is determined that the path containing the first terminal is the path from the source terminal to the target terminal, a first discovery response message is sent to the first terminal.

[0150] The first discovery response message is used to assist the first terminal in determining the next hop node of the first terminal in the path from the source terminal to the target terminal.

[0151] In some embodiments, the first discovery response message includes information about the source terminal and information about the target terminal.

[0152] For example, the source terminal information in the first discovery response message includes the identifier of the source terminal, and the target terminal information in the first discovery response message includes the identifier of the target terminal and the layer 2 link identifier used by the target terminal for direct communication.

[0153] In some embodiments, the first discovery response message includes, in addition to the information of the source terminal and the information of the target terminal, at least one of the relay service code supported by the source terminal and the second hop number, wherein the second hop number is the total number of hops on the path from the source terminal to the target terminal.

[0154] In this embodiment, the above steps design a discovery request and response process for multi-hop communication paths executed by a third terminal in proximity services. This enables efficient and reliable determination of the communication path between the source terminal and the target terminal via one or more relay terminals. In this way, multi-hop communication can be achieved without relying on the network, utilizing terminal resources (including processing power and spectrum) to achieve the communication purpose, and saving network deployment costs.

[0155] Figure 4 This is a flowchart illustrating a method for determining a path according to some embodiments of the present disclosure. Figure 4 The path determination method shown is executed by a third terminal, which can be either a relay terminal or a target terminal. For example... Figure 4 As shown, the path determination method in some embodiments of this disclosure includes steps S410 to S450. Embodiments of this disclosure and... Figure 3 The main difference in the illustrated embodiment is the addition of steps S440 to S450. Therefore, steps S440 to S450 will be described below.

[0156] In step S410, a second discovery request message is received from the first terminal.

[0157] The first terminal is a relay terminal.

[0158] In step S420, if it is determined that it is the target terminal, it is determined whether to use the path containing the first terminal as the path from the source terminal to the target terminal according to the second discovery request message.

[0159] In step S430, if it is determined that the path containing the first terminal is the path from the source terminal to the target terminal, a first discovery response message is sent to the first terminal.

[0160] In this embodiment of the disclosure, after the discovery request sub-process initiated by the source terminal is completed, the target terminal initiates a discovery response sub-process. After the discovery response sub-process is completed, the source terminal initiates a connection establishment sub-process.

[0161] In step S440, a second path establishment request is received from the first terminal.

[0162] In some embodiments, step S440 includes receiving a second path establishment request from the first terminal within a third duration. The third duration is calculated from the time the third terminal determines the path information from the source terminal to the target terminal. Specifically, the third terminal may start a third timer to count the third duration after determining the path information from the source terminal to the target terminal.

[0163] In some embodiments, the path determination method further includes: deleting the path information from the source terminal to the target terminal if no second path establishment request is received within a third time period.

[0164] In this embodiment of the disclosure, considering scenarios with multiple target terminals, there may be situations where multiple paths from the source terminal to multiple target terminals are determined through the discovery request subprocess, and a single path is selected from these paths through the discovery response subprocess. In this case, by deleting the information of the path from the source terminal to the target terminal stored by the third terminal (e.g., the information of the previous hop node in the path from the source terminal to the target terminal) after no second path establishment request is received within a third time period, the resource overhead caused by the continuous storage of node information by target terminals located outside the finally selected path can be reduced.

[0165] In step S450, a direct communication path is established with the first terminal.

[0166] In this embodiment, the above steps design a discovery request, discovery response, and connection establishment process executed by a third terminal in a multi-hop communication path within the proximity service. This enables efficient and reliable determination of the communication path between the source terminal and the target terminal via one or more relay terminals. In this way, multi-hop communication can be achieved without relying on the network, utilizing terminal resources (including processing power and spectrum) to achieve the communication purpose, and saving network deployment costs.

[0167] Figure 5 This is a schematic diagram illustrating the principle of a path determination method according to some embodiments of this disclosure. For example... Figure 5 As shown, the process of establishing a relay communication path between the source terminal and the target terminal includes a discovery request sub-process, a discovery response sub-process, and a connection establishment sub-process.

[0168] The discovery request subprocess is used to determine the relay communication path from the target terminal to the source terminal; the discovery response subprocess is used to determine the relay communication path from the source terminal to the target terminal; and the connection establishment subprocess is used to establish the relay communication path from the source terminal to the target terminal.

[0169] In the discovery request sub-process, the source terminal sends a discovery request message via broadcast. In some embodiments, the discovery request message sent by the source terminal includes information about the target terminal, such as the target terminal's identifier or a capability identifier that the target terminal needs to support. The discovery request message sent by the source terminal will be broadcast to other terminals (e.g., Figure 5 The relay terminal 1 and relay terminal 2 in the middle) received it.

[0170] After receiving discovery request messages from multiple terminals, the relay terminal selects one of the multiple terminals as the previous hop node on the path from the source terminal to the target terminal, based on the received discovery request messages, and then broadcasts the discovery response message.

[0171] For example, if relay terminal 1 receives discovery request messages from both the source terminal and relay terminal 2, it selects one of them as the previous hop node on the path from the source terminal to the target terminal, and then broadcasts the discovery request message. Similarly, if relay terminal 3 receives discovery request messages from both relay terminal 1 and relay terminal 4, it selects one of them as the previous hop node on the path from the source terminal to the target terminal, and then broadcasts the discovery request message.

[0172] After receiving discovery request messages from multiple terminals, the target terminal selects one of the multiple terminals as the previous hop node on the path from the source terminal to the target terminal, based on the received discovery request messages, thereby determining a relay communication path from the target terminal to the source terminal.

[0173] For example, if the target terminal receives a discovery request message from relay terminal 3 and relay terminal 4, it will select one of relay terminals 3 and 4 as the previous hop node on the path from the source terminal to the target terminal, which is located before itself.

[0174] In some embodiments, for a terminal that has determined the previous hop node on the path from the source terminal to the target terminal, if a discovery request message is subsequently received, the discovery request message can be discarded.

[0175] In some embodiments, the relay terminal and the target terminal may select the previous hop node on the path from the source terminal to the target terminal in various ways. For example, the previous hop node on the path from the source terminal to the target terminal may be selected based on one or more factors such as the number of hops carried in the received discovery request message, the time when the discovery request message was received, the signal strength of the discovery request message, or the cumulative signal strength of multiple messages.

[0176] In the discovery response sub-process, the target terminal returns a discovery response message to its selected upstream node. For example, if the target terminal selects relay terminal 3 as the upstream node on the path from the source terminal to the target terminal, and it is located before itself, then it sends a discovery response message to relay terminal 3.

[0177] After receiving a discovery response message, the relay terminal designates the sender of the discovery response message as the next-hop node following itself on the path from the source terminal to the target terminal, and then sends a discovery response message to its previous-hop node. For example, if relay terminal 3 receives a discovery response message from the target terminal, it designates the target terminal as the next-hop node following itself on the path from the source terminal to the target terminal, and then sends a discovery response message to its determined previous-hop node (e.g., ...). Figure 5 The relay terminal 1) sends a discovery response message.

[0178] If a source terminal receives a discovery response message from only one terminal, it will consider the sender of the discovery response message as the next hop node on the path from the source terminal to the target terminal, following itself.

[0179] When a source terminal receives discovery response messages from multiple terminals (e.g., a service the source terminal wants to discover has multiple target terminals), it selects one of the multiple terminals as the next-hop node following itself on the path from the source terminal to the target terminal. In some embodiments, the source terminal selects the next-hop node following itself on the path from the source terminal to the target terminal based on one or more factors such as the number of hops carried in the received discovery response message, the time of receiving the discovery response message, the signal strength of the discovery response message, or the cumulative signal strength of multiple messages.

[0180] In the connection establishment sub-process, after determining the path from the source terminal to the target terminal, the source terminal sends a path establishment request to the next-hop node on that path, following itself. For example, the source terminal sends a path establishment request to... Figure 5 Relay terminal 1 in the middle sends a path establishment request.

[0181] After receiving a connection establishment request, the relay terminal establishes a communication path with the previous hop node in the path from the source terminal to the target terminal, and sends a connection establishment request to the next hop node in the path from the source terminal to the target terminal, until a communication path between the source terminal and the target terminal is established.

[0182] In some embodiments, for relay terminals (e.g., relay terminal 2 and relay terminal 4) and target terminals that do not receive a discovery response message or a path establishment request within a set time period, the information of nodes on the previously determined path is deleted.

[0183] In the embodiments of this disclosure, the above method can be used to establish either a one-hop relay communication path through a single relay terminal or a multi-hop relay communication path through multiple relay terminals. This allows for multi-hop communication without relying on the network, utilizing terminal resources (including processing power and spectrum) to achieve the communication purpose, and saving network deployment costs.

[0184] Figure 6 This is a schematic diagram illustrating the propagation path of a discovery message according to some embodiments of this disclosure.

[0185] like Figure 6 As shown, the source terminal S needs to establish communication with the target terminal T. The target terminal T can be a specific terminal with a unique identifier, or it can be a terminal with a certain capability. For example, if multiple terminals in the scenario possess this service capability, the source terminal S can select one from among the multiple target terminals.

[0186] Communication between source terminal S and target terminal T can occur through multiple relay-enabled terminals (e.g., terminals A to I) within a certain spatial range, resulting in various multi-hop paths. For example, paths 1 to 4 exist, namely {S, A, D, H, T}, {S, B, E, I, T}, {S, A, D, F, I, T}, and {S, B, C, E, I, T}. Using the path determination method of this embodiment, path 2 is ultimately determined as the optimal path for communication between S and T, and a communication path is established.

[0187] Figure 7 This is a flowchart illustrating a path determination method according to some embodiments of the present disclosure. Figure 7 As shown, the path determination method includes steps 1 to 12.

[0188] In step 1, the source terminal S sends a discovery request message.

[0189] In some embodiments, the discovery request message broadcast by the source terminal S is based on the discovery request message in 3GPP Proximity Services (ProSe).

[0190] In some embodiments, the discovery request message sent by S carries information about the source terminal S, RSC, information about the target terminal (information about T), and hop count. The information about T can be an identifier of T or an identifier of a capability that T needs to support. For example, in some scenarios, the source terminal S wants to find a target terminal that supports a certain capability, but does not know which specific terminals possess this capability; in this case, the discovery request can carry the identifier of the capability that the target terminal needs to support. The information about S can include the identifier of S and the Layer 2 link identifier used by S for direct communication.

[0191] In step 2, relay terminal B sends a discovery request message.

[0192] Assuming that only relay terminals A and B in the vicinity of the source terminal S can receive the signal sent by S, the discovery request message sent by the source terminal will be received by relay terminals A and B.

[0193] If relay terminal B determines, based on the information from the source terminal and the target terminal, the previous hop node preceding itself on the path between the source and target terminals that is not stored, and if its supported RSC is consistent with the RSC carried in the received discovery request message, then relay terminal B determines and stores the previous hop node preceding itself on the path between the source and target terminals (or, in other words, the previous hop node following itself on the path between the target and source terminals) based on the received discovery request message. For example, the relay terminal may use source terminal S as the previous hop node preceding itself on the path between the source and target terminals. Then, relay terminal B sends a discovery request message. This message includes information about the source and target terminals, as well as its own information as a relay terminal (Relay UE) and the updated hop count (e.g., the hop count obtained by adding one to the hop count of the source terminal). Relay terminal A, upon receiving the discovery request message, also processes it in the same way to determine the previous hop node preceding itself on the path between the source and target terminals and sends out a discovery request message.

[0194] In step 3, relay terminal E sends a discovery request message.

[0195] like Figure 6 As shown, assume that a discovery request message sent by relay terminal B is received by relay terminals C and E. Relay terminal E processes the message in a similar manner to relay terminal B, determining the previous hop node (e.g., relay terminal B) on the path from the source terminal to the target terminal. Then, relay terminal E sends a discovery request message. The hop count of the discovery request message sent by relay terminal E is obtained by adding one to the hop count of relay terminal B.

[0196] Relay terminal C also processes the data in a similar way to relay terminal B, determining the previous hop node on the path from the source terminal to the target terminal that is located before relay terminal C (for example, relay terminal B is taken as the previous hop node). After that, the discovery request message sent by relay terminal C is also received by relay terminal E.

[0197] In some embodiments, relay terminal E no longer processes the discovery request message received from relay terminal C because it has already received the discovery request message from relay terminal B and has already designated relay terminal B as the previous hop node.

[0198] In some embodiments, relay terminal E discovers that the hop count of the discovery request message sent by relay terminal C is too high (e.g., greater than the hop count of the discovery request message sent by relay terminal B, or exceeding a set value), and therefore selects relay terminal B as the previous hop node between relay terminal B and relay terminal C.

[0199] In step 4, relay terminal I sends a discovery request message.

[0200] Relay terminal I receives a discovery request message from relay terminal E, as well as discovery request messages forwarded from relay terminals A to D to F. Relay terminal I processes the message in a similar manner to relay terminal E, selecting the previous hop node (e.g., relay terminal E) on the path from the source terminal to the target terminal from relay terminals E and F that precedes relay terminal I.

[0201] In step 5, the target terminal T sends a discovery response message.

[0202] like Figure 6 As shown, target terminal T receives a discovery request message from relay terminal I, as well as discovery request messages forwarded from relay terminals A to D to H. It then selects the previous hop node (e.g., relay terminal I) on the path from the source terminal to the target terminal from relay terminals I and H, prior to target terminal T. Afterward, the target terminal sends a discovery response message to relay terminal I.

[0203] In some embodiments, the discovery response message sent by the target terminal T includes information about the source terminal S, the RSC supported by the source terminal, the identifier of the target terminal T, the Layer 2 link identifier (or Layer 2 ID) for direct communication between the target terminal, and the hop count. In some embodiments, the hop count carried in the discovery response message is the total number of hops along the path from the source terminal to the target terminal.

[0204] In some embodiments, the discovery response message is a discovery response message based on 3GPP Proximity Services (ProSe).

[0205] In step 6, relay terminal I sends a discovery response message to relay terminal E.

[0206] After receiving the discovery response message from the target terminal T, relay terminal I designates target terminal T as the next-hop node on the path from the source terminal to the target terminal, following itself. Then, relay terminal I sends a discovery response message to relay terminal E.

[0207] In some embodiments, the discovery response message processing sent by relay terminal I includes information about the source terminal and the target terminal, the hop count, and information about itself as a relay terminal (such as the relay terminal's identifier and Layer 2 ID).

[0208] In step 7, relay terminal E sends a discovery response message to relay terminal B.

[0209] After receiving the discovery response message from the target terminal I, relay terminal E designates relay terminal I as the next-hop node on the path from the source terminal to the target terminal, following itself. Then, relay terminal E sends a discovery response message to relay terminal B.

[0210] In some embodiments, the discovery response message sent by relay terminal E includes information about the source terminal and the target terminal, the hop count, and information about itself as a relay terminal (such as the relay terminal's identifier and Layer 2 ID).

[0211] In step 8, relay terminal B sends a discovery response message to source terminal S.

[0212] After receiving the discovery response message from relay terminal E, relay terminal B designates relay terminal E as the next-hop node on the path from the source terminal to the target terminal. Then, relay terminal E sends a discovery response message to the source terminal S.

[0213] In step 9, the source terminal S sends a path establishment request to the relay terminal B.

[0214] After receiving a discovery response message, the source terminal determines the next-hop node following itself on the path from the source terminal to the target terminal. If there are multiple target terminals T, the source terminal may receive discovery response messages from different terminals. The source terminal S selects one of the multiple terminals as the next-hop node following itself on the path from the source terminal to the target terminal. Then, the source terminal sends a path establishment request to the selected terminal.

[0215] In some embodiments, the path establishment request is a direct communication request in the PC5 connection establishment process based on 3GPP ProSe.

[0216] In steps 10 to 12, relay terminals B, E, and I sequentially establish communication connections with the next-hop node, thus ultimately establishing a communication path from the source terminal to the target terminal. Subsequent communication messages and data between the source terminal S and the target terminal T can then be transmitted through this path.

[0217] In some embodiments, for relay terminals (e.g., relay terminals A, C, D, F, H) and target terminal T that do not receive a discovery response message or a path establishment request within a set time period, the nodes on the path determined in the previous steps are deleted.

[0218] In this embodiment, the above method can establish both one-hop relay communication paths via a single relay terminal and multi-hop relay communication paths via multiple relay terminals. Furthermore, it can meet the path establishment requirements in scenarios where the target terminal is known, as well as in scenarios where the target terminal is unknown. In this way, multi-hop communication can be achieved through these relay terminals without relying on the network, utilizing the terminal's resources (including processing power and spectrum) to achieve the communication purpose, and saving network deployment costs.

[0219] Figure 8 This is a schematic diagram of the structure of a first terminal according to some embodiments of the present disclosure. The first terminal is a relay terminal. Figure 8 As shown, the first terminal 80 includes a receiving module 81, a judging module 82, a determining module 83, and a sending module 84.

[0220] The receiving module 81 is configured to receive a first discovery request message from a second terminal. The first discovery request message includes information about the source terminal and information about the target terminal. The second terminal is either a source terminal or a relay terminal.

[0221] The judgment module 82 is configured to determine, based on the information of the source terminal and the information of the target terminal, whether the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored.

[0222] The determination module 83 is configured to determine and store the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal based on the first discovery request message, when the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal is not stored.

[0223] The sending module 84 is configured to send a second discovery request message to a third terminal. The second discovery request message includes information about the source terminal, information about the first terminal, and information about the target terminal. It is used to assist the third terminal in determining the information of the previous hop node of the third terminal in the path from the source terminal to the target terminal. The third terminal is either the target terminal or a relay terminal.

[0224] In some embodiments, the first terminal is further configured to execute Figure 2 The example shown includes the discovery response sub-process and the connection establishment sub-process.

[0225] In this embodiment of the disclosure, the discovery request process in the multi-hop communication path of the proximity service is implemented through the first terminal, thereby enabling efficient and reliable determination of the communication path between the source terminal and the target terminal through one or more relay terminals.

[0226] Figure 9This is a schematic diagram of the structure of a third terminal according to some embodiments of the present disclosure. For example... Figure 3 As shown, the third terminal includes a receiving module 91, a judging module 92, and a sending module 93.

[0227] The receiving module 91 is configured to receive a second discovery request message from the first terminal. The second discovery request message includes information about the source terminal, the first terminal, and the target terminal; the first terminal is a relay terminal.

[0228] The judgment module 92 is configured to, when the third terminal is determined to be the target terminal, determine whether to use the path containing the first terminal as the path from the source terminal to the target terminal based on the second discovery request message.

[0229] The sending module 93 is configured to send a first discovery response message to the first terminal when it is determined that the path containing the first terminal is the path from the source terminal to the target terminal. The first discovery response message is used to assist the first terminal in determining the information of the next hop node in the path from the source terminal to the target terminal.

[0230] In some embodiments, the third terminal is further configured to execute Figure 4 The connection establishment sub-process in the illustrated embodiment.

[0231] In this embodiment of the disclosure, the discovery request and other processes in the multi-hop communication path of the proximity service are implemented through a third terminal, thereby enabling efficient and reliable determination of the communication path between the source terminal and the target terminal through one or more relay terminals.

[0232] Figure 10 This is a schematic diagram of the structure of a communication system according to some embodiments of the present disclosure. For example... Figure 10 As shown, the communication system 100 includes a first terminal 101, a second terminal 102, and a third terminal 103.

[0233] The first terminal 101 is configured to receive a first discovery request message from the second terminal 102.

[0234] Among them, the first terminal 101 is a relay terminal, and the second terminal 102 is a source terminal or a relay terminal.

[0235] In some embodiments, the second terminal 102 broadcasts the first discovery request message. In addition to the first terminal 101 receiving the first discovery request message, other terminals, including terminal m 104, also receive the first discovery request message.

[0236] The first discovery request message includes information about the source terminal and information about the target terminal.

[0237] The first terminal 101 is also configured to determine, based on the information of the source terminal and the information of the target terminal, whether the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored.

[0238] The first terminal 101 is also configured to determine and store the information of the previous hop node in the path from the source terminal to the target terminal based on the first discovery request message, even if the information of the previous hop node in the path from the source terminal to the target terminal is not stored.

[0239] The first terminal 101 is also configured to send a second discovery request message. The second discovery request message includes information about the source terminal, information about the first terminal, and information about the target terminal.

[0240] The third terminal 103 is configured to receive a second discovery request message from the first terminal 101.

[0241] In some embodiments, the first terminal 101 broadcasts a second discovery request message. In addition to the third terminal 103 receiving the second discovery request message, other terminals, including terminal n 105, also receive the second discovery request message.

[0242] The third terminal 103 is also configured to, upon determining that it belongs to the target terminal, determine whether to use the path containing the first terminal as the path from the source terminal to the target terminal based on the second discovery request.

[0243] In this embodiment of the disclosure, the discovery request process is completed jointly by multiple terminals, including the first terminal to the third terminal, which helps to efficiently and reliably determine the communication path between the source terminal and the target terminal through one or more relay terminals.

[0244] In some embodiments, the third terminal 103 is further configured to: send a first discovery response message to the first terminal when it is determined that the path including the first terminal is the path from the source terminal to the target terminal. The first discovery response message includes information about the source terminal and information about the target terminal, used to assist the first terminal in determining the information of the next-hop node in the path from the source terminal to the target terminal.

[0245] In some embodiments, the first terminal 101 is further configured to: upon receiving a first discovery response message from a third terminal within a first duration, determine and store information about the next-hop node in the path from the source terminal to the target terminal based on the first discovery response message; and send a second discovery response message to the previous-hop node in the path from the source terminal to the target terminal determined therein. The second discovery response message includes information about the source terminal, information about the first terminal, and information about the target terminal.

[0246] In this embodiment of the disclosure, the discovery request and discovery response process is completed jointly by multiple terminals, including the first terminal to the third terminal, which helps to efficiently and reliably determine the communication path between the source terminal and the target terminal through one or more relay terminals.

[0247] In some embodiments, when the second terminal 102 is the source terminal, the second terminal 102 is further configured to: upon receiving a second discovery response message from the first terminal, send a first path establishment request to the first terminal to establish a direct communication path with the first terminal.

[0248] In some embodiments, when the second terminal 102 is the source terminal, the second terminal 102 is further configured to: upon receiving multiple discovery response messages, including a second discovery response message, determine whether to use the first terminal as the next-hop node in the path from the source terminal to the target terminal; if it is determined that the first terminal is the next-hop node in the path from the source terminal to the target terminal, send a first path establishment request to the first terminal 101 to establish a direct communication path with the first terminal. This configuration better meets the path establishment requirements in scenarios where there are multiple target terminals.

[0249] In some embodiments, the second terminal 102 determines whether to use the first terminal as the next-hop node of the second terminal in the path from the source terminal to the target terminal based on a plurality of discovery response messages, including: determining whether to use the first terminal as the next-hop node of the second terminal in the path from the source terminal to the target terminal based on at least one of the following: the time of receiving the plurality of discovery response messages, the number of hops carried by the plurality of discovery response messages, the signal strength of the plurality of discovery response messages, and the multi-hop cumulative signal strength corresponding to each of the plurality of discovery response messages.

[0250] In this embodiment of the disclosure, the discovery request, discovery response, and connection establishment process are completed jointly by multiple terminals, including the first terminal to the third terminal, which helps to efficiently and reliably determine the communication path between the source terminal and the target terminal through one or more relay terminals.

[0251] Figure 11 This is a schematic diagram of the structure of an electronic device according to some embodiments of the present disclosure.

[0252] like Figure 11 As shown, the electronic device 110 includes a memory 111 and a processor 112 coupled to the memory 111. The memory 111 is used to store instructions for executing embodiments of the path determination method. The processor 112 is configured to execute the path determination method in any of the embodiments of this disclosure based on the instructions stored in the memory 111.

[0253] Figure 12 This is a schematic diagram of the structure of a computer system according to some embodiments of the present disclosure.

[0254] like Figure 12 As shown, the computer system 120 can be represented in the form of a general computing device. The computer system 120 includes a memory 121, a processor 122, and a bus 123 connecting different system components.

[0255] The memory 121 may include, for example, system memory, non-volatile storage media, etc. The system memory may store, for example, an operating system, application programs, a boot loader, and other programs. The system memory may include volatile storage media, such as random access memory (RAM) and / or cache memory. The non-volatile storage media may store, for example, instructions for a corresponding embodiment of at least one robot scheduling method being executed. Non-volatile storage media include, but are not limited to, disk storage, optical storage, flash memory, etc.

[0256] The processor 122 can be implemented using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete hardware components such as discrete gates or transistors. Accordingly, each module, such as the receiving module, the judging module, the determining module, and the transmitting module, can be implemented by executing instructions in the central processing unit (CPU) memory to perform the corresponding steps, or by implementing dedicated circuits that perform the corresponding steps.

[0257] Bus 123 can use any of the various bus architectures. For example, bus architectures include, but are not limited to, the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MCA) bus, and the Peripheral Component Interconnect (PCI) bus.

[0258] The computer system 120 can be connected via bus 123 to interfaces 124, 125, and 126, as well as to memory 121 and processor 122. Input / output interface 124 provides a connection interface for input / output devices such as monitors, mice, and keyboards. Network interface 125 provides a connection interface for various networked devices. Storage interface 126 provides a connection interface for external storage devices such as floppy disks, USB flash drives, and SD cards.

[0259] Various aspects of this disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus, and computer program products according to embodiments of this disclosure. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations thereof, can be implemented by computer-readable program instructions.

[0260] These computer-readable program instructions are provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable device to produce a machine, such that execution of the instructions by the processor produces means for implementing the functions specified in one or more boxes of the flowchart and / or block diagram.

[0261] These computer-readable program instructions may also be stored in a computer-readable storage medium. These instructions cause a computer to work in a particular manner to produce an article of manufacture, including instructions that implement the functions specified in one or more boxes in a flowchart and / or block diagram.

[0262] This disclosure may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0263] The path determination method, terminal, and communication system described in the above embodiments can efficiently and reliably establish a communication path for two terminals to communicate through one or more relay terminals.

[0264] The path determination method, terminal, and communication system according to this disclosure have been described in detail above. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

Claims

1. A path determination method, executed by a first terminal, comprising: A first discovery request message is received from the second terminal. The first discovery request message includes information about the source terminal and information about the target terminal. The first terminal is a relay terminal, and the second terminal is either the source terminal or a relay terminal. Based on the information of the source terminal and the information of the target terminal, determine whether the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored; If the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal is not stored, the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal is determined and stored according to the first discovery request message. as well as Send a second discovery request message to a third terminal. The second discovery request message includes information about the source terminal, information about the first terminal, and information about the target terminal. It is used to assist the third terminal in determining the information of the previous hop node of the third terminal in the path from the source terminal to the target terminal. The third terminal is the target terminal or a relay terminal. The method further includes: If the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has already been stored, the first discovery request message is discarded.

2. The path determination method according to claim 1 further includes: If a first discovery response message is received within a first duration, the information of the next-hop node of the first terminal in the path from the source terminal to the target terminal is determined and stored according to the first discovery response message. The first discovery response message includes information of the source terminal and information of the target terminal. The first duration is started from the time after the information of the previous-hop node of the first terminal in the path from the source terminal to the target terminal is determined. as well as A second discovery response message is sent to the previous hop node of the first terminal in the path from the source terminal to the target terminal. The second discovery response message includes at least one of the relay service code supported by the source terminal and the second hop number, information of the source terminal, information of the first terminal, and information of the target terminal. The second hop number is the total number of hops in the path from the source terminal to the target terminal.

3. The path determination method according to claim 2 further includes: If no first discovery response message is received within the first time period, the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal is deleted.

4. The path determination method according to claim 2 further includes: If a first path establishment request is received from the previous hop node of the first terminal within a second time period, a direct communication path is established with the previous hop node of the first terminal. The second time period begins after determining the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal, and the information of the next hop node of the first terminal in the path from the source terminal to the target terminal. Send a second path establishment request to the next-hop node of the first terminal.

5. The path determination method according to claim 4 further includes: If no first path establishment request is received from the previous hop node of the first terminal within the second time period, the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal and the information of the next hop node of the first terminal in the path from the source terminal to the target terminal are deleted.

6. The path determination method according to claim 1, wherein, The first discovery request message further includes at least one of the relay service code supported by the source terminal and the first hop count. In the case that the second terminal is a relay terminal, the first discovery request message also includes information about the second terminal. The first hop count is the number of hops accumulated from the source terminal. The information about the second terminal includes at least one of the identifier of the second terminal and the layer 2 link identifier used by the second terminal for direct communication.

7. The path determination method according to claim 6, wherein determining and storing the information of the previous hop node in the path from the source terminal to the target terminal based on the first discovery request message includes: Based on at least one of the time the first discovery request message was received, the first hop count, the signal strength of the first discovery request message, and the multi-hop cumulative signal strength, determine and store the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal.

8. The path determination method according to claim 1, wherein, The source terminal information in the first discovery request message includes at least one of the source terminal's identifier and the Layer 2 link identifier used by the source terminal for direct communication. The target terminal information in the first discovery request message includes the target terminal's identifier or the capability identifier that the target terminal needs to support.

9. The path determination method according to claim 2, wherein, The first discovery response message also includes at least one of the relay service code supported by the source terminal and the second hop count, where the second hop count is the total number of hops of the path from the source terminal to the target terminal.

10. The path determination method according to claim 2, wherein, The source terminal information in the first discovery response message includes the identifier of the source terminal, and the target terminal information in the first discovery response message includes the identifier of the target terminal and the Layer 2 link identifier used by the target terminal for direct communication.

11. A path determination method, executed by a third terminal, comprising: A second discovery request message is received from the first terminal. The second discovery request message includes information about the source terminal, information about the first terminal, and information about the target terminal. The first terminal is a relay terminal. If the device is identified as the target terminal, the system determines, based on the second discovery request message, whether to use the path containing the first terminal as the path from the source terminal to the target terminal. This includes: determining, based on the information of the source terminal and the information of the target terminal, whether the path information from the source terminal to the target terminal has been stored; if the path information from the source terminal to the target terminal has not been stored, determining, based on the second discovery request message, whether to use the path containing the first terminal as the path from the source terminal to the target terminal; if the path information from the source terminal to the target terminal has been stored, discarding the second discovery request message. If it is determined that the path containing the first terminal is the path from the source terminal to the target terminal, a first discovery response message is sent to the first terminal. The first discovery response message is used to assist the first terminal in determining the information of the next-hop node of the first terminal in the path from the source terminal to the target terminal.

12. The path determination method according to claim 11, further comprising: If a second path establishment request is received from the first terminal within a third time period, a direct communication path with the first terminal is established. The third time period is the time count that begins after the third terminal determines the path information from the source terminal to the target terminal.

13. The path determination method according to claim 12, further comprising: If no second path establishment request is received from the first terminal within a third time period, the path information from the source terminal to the target terminal is deleted.

14. The path determination method according to claim 11, wherein, The second discovery request message also includes at least one of a third hop count and a relay service code supported by the source terminal. The step of determining whether to use the path containing the first terminal as the path from the source terminal to the target terminal based on the second discovery request message includes: Based on at least one of the time the second discovery request message was received, the third hop count, the signal strength of the second discovery request message, and the multi-hop cumulative signal strength, it is determined whether to use the path containing the first terminal as the path from the source terminal to the target terminal, where the third hop count is the cumulative hop count starting from the source terminal.

15. A first terminal, comprising: The receiving module is configured to receive a first discovery request message from a second terminal. The first discovery request message includes information about a source terminal and information about a target terminal. The first terminal is a relay terminal, and the second terminal is either the source terminal or the relay terminal. The judgment module is configured to determine, based on the information of the source terminal and the information of the target terminal, whether the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored. The determination module is configured to determine and store the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal based on the first discovery request message, when the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal is not stored. as well as The sending module is configured to send a second discovery request message to a third terminal. The second discovery request message includes information about the source terminal, information about the first terminal, and information about the target terminal. It is used to assist the third terminal in determining the information of the previous hop node of the third terminal in the path from the source terminal to the target terminal. The third terminal is the target terminal or a relay terminal. The discard module is configured to discard the first discovery request message if information about the previous hop node of the first terminal in the path from the source terminal to the target terminal has already been stored.

16. A third terminal, comprising: The receiving module is configured to receive a second discovery request message from a first terminal, the second discovery request message including information of a source terminal, information of the first terminal and information of a target terminal, wherein the first terminal is a relay terminal; The determination module is configured to, when the third terminal is determined to be the target terminal, determine, based on the second discovery request message, whether to use the path containing the first terminal as the path from the source terminal to the target terminal, including: determining, based on the information of the source terminal and the information of the target terminal, whether the path information from the source terminal to the target terminal has been stored; if the path information from the source terminal to the target terminal has not been stored, determining, based on the second discovery request message, whether to use the path containing the first terminal as the path from the source terminal to the target terminal; if the path information from the source terminal to the target terminal has been stored, discarding the second discovery request message. The sending module is configured to send a first discovery response message to the first terminal when it is determined that the path containing the first terminal is the path from the source terminal to the target terminal. The first discovery response message is used to assist the first terminal in determining the information of the next hop node in the path from the source terminal to the target terminal.

17. A communication system, comprising: The first terminal is configured as follows: A first discovery request message is received from a second terminal, where the first terminal is a relay terminal and the second terminal is a source terminal or a relay terminal. The first discovery request message includes information about the source terminal and information about the target terminal. Based on the information of the source terminal and the information of the target terminal, determine whether the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has been stored; If the information of the previous hop node in the path from the source terminal to the target terminal is not stored, the information of the previous hop node in the path from the source terminal to the target terminal is determined and stored according to the first discovery request message; as well as Send a second discovery request message, the second discovery request message including information about the source terminal, information about the first terminal and information about the target terminal; If the information of the previous hop node of the first terminal in the path from the source terminal to the target terminal has already been stored, the first discovery request message is discarded. The third terminal is configured as follows: Receive the second discovery request message from the first terminal; If it is determined that it belongs to the target terminal, it determines whether to use the path containing the first terminal as the path from the source terminal to the target terminal according to the second discovery request.

18. The communication system according to claim 17, wherein, The third terminal is also configured to: If it is determined that the path containing the first terminal is the path from the source terminal to the target terminal, a first discovery response message is sent to the first terminal. The first discovery response message includes information about the source terminal and information about the target terminal, and is used to assist the first terminal in determining the information of the next hop node in the path from the source terminal to the target terminal.

19. The communication system according to claim 18, wherein, The first terminal is also configured as follows: If a first discovery response message is received within a first time period, the information of the next-hop node in the path from the source terminal to the target terminal is determined and stored based on the first discovery response message. as well as A second discovery response message is sent to the previous hop node in the path from the source terminal to the target terminal as determined therein. The second discovery response message includes at least one of the relay service code supported by the source terminal and the second hop number, information of the source terminal, information of the first terminal, and information of the target terminal. The second hop number is the total number of hops in the path from the source terminal to the target terminal.

20. The communication system according to claim 17, further comprising the second terminal, wherein, When the second terminal is the source terminal, the second terminal is configured as follows: Upon receiving the second discovery response message from the first terminal, a first path establishment request is sent to the first terminal to establish a direct communication path with the first terminal.

21. The communication system according to claim 17, further comprising the second terminal, wherein, When the second terminal is the source terminal, the second terminal is also configured as follows: Upon receiving multiple discovery response messages, including a second discovery response message, determine whether to use the first terminal as the next-hop node of the second terminal in the path from the source terminal to the target terminal based on the multiple discovery response messages. If it is determined that the second terminal is the next-hop node in the path from the first terminal to the target terminal, a first path establishment request is sent to the first terminal to establish a direct communication path with the first terminal.

22. The communication system according to claim 21, wherein, Determining whether to include the first terminal as the next-hop node of the second terminal in the path from the source terminal to the target terminal based on the multiple discovery response messages includes: Based on at least one of the following: the time when the plurality of discovery response messages are received, the number of hops carried by the plurality of discovery response messages, the signal strength of the plurality of discovery response messages, and the cumulative signal strength of the multi-hops corresponding to each of the plurality of discovery response messages, it is determined whether the first terminal is to be used as the next-hop node of the second terminal in the path from the source terminal to the target terminal.

23. An electronic device, comprising: Memory; as well as A processor coupled to the memory, the processor being configured to execute the path determination method as described in any one of claims 1 to 14 based on instructions stored in the memory.

24. A computer-readable storage medium having stored thereon computer program instructions that, when executed by a processor, implement the path determination method as described in any one of claims 1 to 14.

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