Method for configuring wireless mesh network

Abstract

The present invention relates to a method for configuring a wireless mesh network and, more particularly, to a method for configuring a wireless mesh network which configures an optimal network minimizing network load while maintaining desired connectivity by preserving network coverage even in the event of a failure in a wireless network device.

Description

How to configure a wireless mesh network

[0001] The present invention relates to a method for configuring a wireless mesh network, and more specifically, to a method for configuring a wireless mesh network that minimizes network load while maintaining target connectivity by maintaining network coverage even if a failure occurs in a wireless network device.

[0002] Recently, wireless mesh network technology is gaining attention for reducing network infrastructure construction and maintenance costs and providing high reliability by multiplexing packet transmission paths.

[0003] A wireless mesh network refers to a network configured to enable communication with distant devices through sequential communication between adjacent devices without a centralized router. It is characterized by low infrastructure construction costs, easy scalability, and high reliability due to robust connectivity.

[0004] However, due to the nature of wireless mesh network technology, high connectivity causes a large amount of packet regeneration, which increases network load and reduces packet throughput.

[0005] The present invention aims to solve the above-mentioned problems by providing a wireless mesh network configuration method that configures an optimal network that minimizes network load while maintaining target connectivity by maintaining network coverage even when a failure occurs in a wireless network device.

[0006] According to one embodiment of the present invention for achieving the above-mentioned purpose, a method for configuring a fault-tolerant wireless mesh network by selecting a relay node that transmits packets among a plurality of nodes is provided, comprising the steps of calculating network configuration information of the nodes, selecting a relay node among a plurality of nodes, and releasing an unnecessary relay node among the selected relay nodes, wherein the wireless mesh network satisfies the number of exclusive paths composed only of non-overlapping nodes so as to have the desired fault tolerance.

[0007] In addition, the step of selecting a relay node according to one embodiment of the present invention includes the step of selecting a relay candidate node among the plurality of nodes and the step of changing the relay candidate node into a relay node based on the connection score of the relay candidate node, the relay order which is the number of adjacent relay nodes, and the order which is the number of adjacent nodes, wherein the connection score is calculated based on the number of exclusive paths and the relay order.

[0008] In addition, the step of changing a relay candidate node into a relay node according to one embodiment of the present invention is characterized by determining the relay order of an adjacent node, and using the sum of the difference between the relay order of a node among the adjacent nodes and the minimum exclusive path number, where each relay order is smaller than the minimum exclusive path number required to achieve the target fault tolerance, as a connection score.

[0009] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized by, in the step of changing a relay candidate node into a relay node, if there is a strongly connected node whose relay order is greater than or equal to the minimum exclusive path number, changing it into a relay node preferentially.

[0010] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized in that, in the step of changing a relay candidate node into a relay node, if there is a strongly connected node among the relay candidate nodes, the relay node is determined based on the connection score, relay order, and order of each strongly connected node.

[0011] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized by determining a relay node based on the connection score, relay order, and order of each weakly connected node, where the relay order is less than the minimum exclusive path number, when there is no strongly connected node among the relay candidate nodes in the step of changing a relay candidate node to a relay node.

[0012] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized in that, in the step of changing a relay candidate node into a relay node, if there is no strongly connected node among the relay candidate nodes, the relay node is determined based on the connection score and degree of the weakly connected node with the largest relay degree among the weakly connected nodes.

[0013] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized in that, in the step of changing a relay candidate node to a relay node, whenever a relay candidate node is changed to a relay node, the information of the changed node and adjacent nodes is updated, and the information includes at least one of whether it is a strongly connected node, a connection score, and a relay order.

[0014] In addition, the wireless mesh network configuration method according to one embodiment of the present invention is characterized in that the step of changing relay candidate nodes into relay nodes is repeated until all nodes are changed into strongly connected nodes or until there are no remaining relay candidate nodes.

[0015] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized by changing a fixed node into a relay node when all nodes are changed to strongly connected nodes or when the remaining relay candidate nodes are eliminated during the step of changing the relay candidate node into a relay node.

[0016] In addition, the step of releasing an unnecessary relay node according to one embodiment of the present invention is characterized by including the step of selecting the relay node as a relay release candidate node, the step of determining whether to release the node after selecting one of the relay release candidate nodes, and the step of releasing the relay release candidate node from the relay node according to the determination.

[0017] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized by selecting one of the relay release candidate nodes and, in the step of determining whether to release, determining to release the relay node if the entire node maintains a strongly connected node state even if the selected node is released.

[0018] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized by selecting one of the relay release candidate nodes and, in the step of determining whether to release, selecting from the nodes with the smallest relay order.

[0019] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized in that, after selecting one of the relay release candidate nodes, in the step of determining whether to release, if there are two or more nodes with the smallest relay order, the node with the smallest order is selected first.

[0020] In addition, a wireless mesh network configuration method according to one embodiment of the present invention is characterized in that, in the step of releasing a relay release candidate node from a relay node according to the above determination, whenever a relay release candidate node is released, the information of the released node and the adjacent node is updated, and the information includes at least one of whether it is a strongly connected node, a connection score, a relay order, and an order.

[0021] Meanwhile, a wireless mesh network configuration method according to another embodiment of the present invention is a method for configuring a fault-tolerant wireless mesh network by selecting a relay node that transmits packets among a plurality of nodes, comprising the steps of calculating network configuration information of a node, calculating a connection factor of a node, selecting a relay node among a plurality of nodes, and releasing an unnecessary relay node among the selected relay node, wherein the wireless mesh network satisfies the number of exclusive paths composed only of non-overlapping nodes so as to have the target fault tolerance, and the connection factor is calculated based on the connection score of a node, the relay order which is the number of adjacent relay nodes, and the order which is the number of adjacent nodes, and the connection score is calculated based on the number of exclusive paths and the relay order.

[0022] In addition, a wireless mesh network configuration method according to another embodiment of the present invention further includes a step of selecting a relay candidate node among a plurality of nodes, wherein the step of calculating the connection factor calculates the connection factor of the selected relay candidate node, and the step of selecting the relay node is characterized by selecting the relay candidate node as a relay node and changing it.

[0023] In addition, a wireless mesh network configuration method according to another embodiment of the present invention is characterized in that, in the step of calculating the connectivity factor of the node, if there is no weakly connected node adjacent to the node, the connectivity factor is considered to be non-existent.

[0024] In addition, a wireless mesh network configuration method according to another embodiment of the present invention is characterized in that, in the step of selecting the relay node, if the relay candidate node has no connection factor, it is excluded from the relay candidate node.

[0025] In addition, a wireless mesh network configuration method according to another embodiment of the present invention is characterized in that, in the step of selecting the relay node, if there is no strongly connected node among the relay candidate nodes, the relay node is determined based on the connection factor of the weakly connected node with the largest relay degree among the weakly connected nodes whose relay degree is less than the minimum exclusive path number.

[0026] In addition, a wireless mesh network configuration method according to another embodiment of the present invention is characterized in that, in the step of selecting the relay node, the node with the largest connection factor among the relay candidate nodes is changed to the relay node.

[0027] In addition, a wireless mesh network configuration method according to another embodiment of the present invention is characterized in that, in the step of determining whether to release a node after selecting one of the relay release candidate nodes, the node with the largest connection release factor among the relay release candidate nodes is selected, and the connection release factor is calculated based on the relay order and order of the node.

[0028] According to one embodiment of the present invention, even if a failure occurs in a wireless network device, it is possible to configure an optimal network that minimizes network load while maintaining target connectivity by maintaining network coverage.

[0029] Figure 1 is a diagram showing the connections between nodes in a wireless mesh network.

[0030] Figure 2 is a diagram illustrating fault tolerance in a wireless mesh network.

[0031] FIG. 3 is a flowchart illustrating a method for configuring a wireless mesh network according to an embodiment of the present invention.

[0032] FIG. 4 is a flowchart illustrating the process of selecting a relay node in a wireless mesh network configuration method according to one embodiment of the present invention.

[0033] FIG. 5 is a flowchart illustrating the process of releasing unnecessary relay nodes in a wireless mesh network configuration method according to an embodiment of the present invention.

[0034] FIGS. 6 to 13 are drawings for explaining the process of configuring a wireless mesh network according to an embodiment of the present invention.

[0035] FIG. 14 is a diagram illustrating a method for configuring a wireless mesh network according to another embodiment of the present invention.

[0036] FIG. 15 is a flowchart illustrating the process of calculating connection factors in a wireless mesh network configuration method according to another embodiment of the present invention.

[0037] FIG. 16 is a flowchart illustrating the process of selecting a relay node in a wireless mesh network configuration method according to another embodiment of the present invention.

[0038] FIG. 17 is a diagram illustrating the process of releasing unnecessary relay nodes in a wireless mesh network configuration method according to another embodiment of the present invention.

[0039] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings.

[0040] Additionally, identical or corresponding components are assigned the same or similar reference numbers regardless of drawing symbols, and redundant descriptions thereof are omitted; furthermore, for the convenience of explanation, the size and shape of each illustrated component may be exaggerated or reduced.

[0041] Figure 1 is a diagram showing the connections between nodes in a wireless mesh network, and Figure 2 is a diagram explaining fault tolerance in a wireless mesh network.

[0042] Referring to FIGS. 1 and 2, a wireless mesh network transmits packets to nodes within a certain range without being directly electrically connected as in FIG. 1 (a). At this time, if lines are connected between nodes capable of communication, it is as in FIG. 1 (b).

[0043] Node I of Fig. 1 is connected to Node J, Node J is connected to Node K, and Node K is connected to Node L to transmit packets.

[0044] In Figure 2, there are two paths from node I to node L, (a) and (b), respectively. In case (a), node K is used redundantly, and if node K fails, the entire path is disconnected. However, in case (b), each node corresponding to the path from node I to node L is not redundant, and a path composed only of non-redundant nodes, excluding the source and destination, is called an exclusive path.

[0045] FIG. 3 is a flowchart illustrating a method for configuring a wireless mesh network according to an embodiment of the present invention, FIG. 4 is a flowchart illustrating a process for selecting a relay node in a method for configuring a wireless mesh network according to an embodiment of the present invention, and FIG. 5 is a flowchart illustrating a process for releasing an unnecessary relay node in a method for configuring a wireless mesh network according to an embodiment of the present invention.

[0046] Referring to FIGS. 3 to 5, a wireless mesh network configuration method according to one embodiment of the present invention may include a step of calculating network configuration information of a node (S110), a step of selecting a relay node among a plurality of nodes (S120), and a step of releasing an unnecessary relay node among the selected relay nodes (S130).

[0047] At this time, a wireless mesh network configured according to one embodiment of the present invention can satisfy the number of exclusive paths composed only of non-overlapping nodes so as to have the desired fault tolerance.

[0048] The step of selecting a relay node (S120) may include the step of selecting a relay candidate node among a plurality of nodes, and the step of changing the relay candidate node into a relay node based on the connection score of the relay candidate node, the relay order which is the number of adjacent relay nodes, and the order which is the number of adjacent nodes.

[0049] Specifically, the step of selecting a relay node (S120) may include the step of inputting network configuration information (S121). In this case, the network configuration information may include the location of each node and whether communication with other nodes is possible.

[0050] Additionally, in the step of selecting a relay node (S120), the step of selecting a relay candidate node may include a step of selecting a fixed node, in which the packet forwarding function is always turned on, as a relay candidate node (S122), and a step of selecting a variable node, in which the packet forwarding function can be turned on and off, as a relay candidate node (S123).

[0051] In this case, since the fixed node always has its packet forwarding function turned on, it is definitively a relay node. However, if the fixed node is selected as a relay node in advance, a situation may arise where the number of exclusive paths in the network is smaller than the minimum number of exclusive paths, even if all nodes correspond to the strongly connected nodes described later.

[0052] For this reason, in the step of selecting relay nodes (S120), the relay node selection process is carried out by treating fixed nodes as variable nodes.

[0053] Meanwhile, the step of selecting a relay node (S120) may include the step of calculating the connection score, relay order, and order of relay candidate nodes (S124).

[0054] In this case, the connection score can be calculated based on the number of exclusive paths and the relay order.

[0055] Specifically, the step of changing a relay candidate node into a relay node may involve determining whether the entire node is a strongly connected node (S125), and if it is a strongly connected node, changing the fixed node into a relay node (S129) and then terminating the step. Here, a strongly connected node refers to a node whose relay degree is greater than or equal to the minimum exclusive path number.

[0056] Additionally, if there is a weakly connected node among all nodes, it is determined whether there is a relay candidate node (S126), and if there is no relay candidate node, the fixed node is changed to a relay node (S129) and the step can be terminated. Here, a weakly connected node refers to a node whose relay degree is less than the minimum exclusive path number.

[0057] Additionally, if there is a relay candidate node, it can be changed to a relay node based on the connection score, relay order, and order of the relay candidate node (S127). At this time, the connection score can be calculated by determining the relay order of an adjacent node, and using the value obtained by calculating the difference between the relay order of a node among the adjacent nodes and the minimum exclusive path number, and the minimum exclusive path number, for which each relay order is smaller than the minimum exclusive path number required to achieve the target fault tolerance.

[0058] That is, the connection score can be expressed as the sum of the difference between the minimum exclusive path number of weakly connected nodes among adjacent nodes and the relay degree, and can be calculated using the following mathematical formula 1.

[0059] [Mathematical Formula 1]

[0060]

[0061] Here, s is the connection score, E is the minimum exclusive path number, and r i represents the relay degree of an adjacent node.

[0062] Meanwhile, during the step of changing relay candidate nodes into relay nodes, if there is a strongly connected node among the relay candidate nodes, it can be changed into a relay node preferentially. In this case, the relay node can be determined based on the connection score, relay degree, and degree of each strongly connected node.

[0063] Specifically, if there is a strongly connected node among the relay candidate nodes, the connection scores of the strongly connected nodes can be compared, and the strongly connected node with the highest connection score can be changed to the relay node. In this case, if there are two or more nodes with the highest connection scores, the relay degrees of the nodes with the highest connection scores can be compared, and the node with the lowest relay degree can be changed to the relay node. Additionally, if there are two or more nodes with the lowest relay degree, the degrees of the nodes with the lowest relay degrees can be compared, and the node with the lowest degree among them can be changed to the relay node.

[0064] In addition, during the step of changing a relay candidate node into a relay node, if there are no strongly connected nodes among the relay candidate nodes, the relay node can be determined based on the connection score, relay degree, and degree of each weakly connected node.

[0065] Specifically, if there are no strongly connected nodes among the relay candidate nodes, the relay degrees of the weakly connected nodes can be compared, and the node with the highest relay degree can be changed to the relay node. As a result, a partially strongly connected network composed of nodes satisfying the minimum exclusive path number can be quickly constructed.

[0066] In this case, if there are two or more nodes with the highest relay degree, the connection scores of the nodes with the highest relay degrees can be compared, and the node with the highest connection score can be changed to the relay node. Additionally, if there are two or more nodes with the highest connection scores, the degrees of the nodes with the highest connection scores can be compared, and the node with the lowest degree can be changed to the relay node.

[0067] In addition, if the conditions of the largest relay order, the largest connection point, and the smallest order mentioned above are all the same, any node can be changed to a relay node.

[0068] Subsequently, when a relay node is determined, the method may include a step (S128) of updating information on the changed node and adjacent nodes. At this time, the information on the node may include at least one of whether it is a strongly connected node, a connection score, and a relay order.

[0069] The step of changing a relay candidate node to a relay node can be performed repeatedly after the step of updating information on the changed node and adjacent nodes (S128), and returning to the step of determining whether the entire node is a strongly connected node (S125) until the entire node is a strongly connected node or there are no relay candidate nodes.

[0070] Meanwhile, the step (S130) of releasing unnecessary relay nodes among the selected relay nodes may include the step of selecting a relay node as a relay release candidate node, the step of determining whether to release a node after selecting one of the relay release candidate nodes, and the step of releasing the relay release candidate node from the relay nodes according to the determination.

[0071] Specifically, the step of releasing unnecessary relay nodes among the relay nodes (S130) may include the step of inputting network configuration information (S131) ​​and the step of selecting variable nodes among the relay nodes as relay release candidate nodes (S132).

[0072] Additionally, in the step of determining whether to release a relay after selecting one of the relay release candidate nodes, it is determined whether there is a relay release candidate node (S133), and if there is a relay release candidate node, the node with the smallest relay degree can be selected first (S134).

[0073] In this case, if there are two or more nodes with the smallest relay degree, the degrees of the nodes with the smallest relay degree can be compared to select the node with the smallest degree.

[0074] Afterwards, it can be determined whether the entire node maintains a strongly connected node state even if the selected relay release candidate node is released (S135), and if the entire node maintains a strongly connected node state even if the selected relay release candidate node is released, the selected relay node can be released (S136).

[0075] Subsequently, when a relay release candidate node is released, the method may include a step (S137) of updating information about the released node and adjacent nodes. At this time, the information of the node may include at least one of whether it is a strongly connected node, a connection score, a relay order, and an order.

[0076] After selecting one of the relay release candidate nodes, the step of determining whether to release and the step of releasing the relay release candidate node from the relay node according to the determination can be performed repeatedly until there are no relay release candidate nodes, by performing the step of updating information of the released node and adjacent nodes (S137) and returning to the step of determining whether there are relay release candidate nodes (S133).

[0077] Additionally, in the step (S135) of determining whether the entire node maintains a strongly connected node state even if the selected relay release candidate node is released, if it is determined that the entire node does not maintain a strongly connected node state when the selected relay release candidate node is released, the selected relay release candidate node is changed to a relay node (S138), and then the process can be repeated by returning to the step (S133) of determining whether there is a relay release candidate node until there is no relay release candidate node.

[0078] FIGS. 6 to 13 are drawings for explaining the process of configuring a wireless mesh network according to an embodiment of the present invention.

[0079] Next, a method for configuring a wireless mesh network according to an embodiment of the present invention will be described in detail with reference to FIGS. 6 to 13. At this time, the minimum exclusive path number is assumed to be 2.

[0080] Figure 6(a) illustrates the process of calculating the connection score of each node. At this time, since the minimum exclusive path number is 2 and the relay degree of all nodes is 0, the connection score of each node is equal to twice the number of adjacent nodes.

[0081] In Figure 6 (a), since there are no strongly connected nodes and no relay nodes, the node corresponding to the largest connection score of 24 is changed to a relay node.

[0082] Figure 7(a) shows that the connection score becomes 10 by 4 adjacent relay order 1(+1) nodes and 3 relay order 0(+2) nodes, and Figure 7(b) shows the connection score of relay order 1 nodes calculated in this way.

[0083] At this time, since there are 4 nodes with a connection score of 14, any node can be selected and changed into a relay node.

[0084] In the case of Fig. 8, since there are strongly connected nodes, the node with the largest connection score of 10 among the strongly connected nodes is selected as the relay node.

[0085] Likewise, in the case of Fig. 9, any node among the strongly connected nodes with the largest connection score of 7 is selected as a relay node, in the case of Fig. 10, a node among the strongly connected nodes with the largest connection score of 6 is selected as a relay node, and in the case of Fig. 11, any node among the strongly connected nodes with the largest connection score of 2 is selected as a relay node.

[0086] At this time, as shown in Fig. 12, seven nodes are selected as relay nodes, and all nodes become strongly connected, so the step of selecting relay nodes is completed.

[0087] Afterwards, as shown in FIG. 13, it is checked whether the strong connection state of the entire node is maintained even if one of the seven relay nodes is disconnected, and the relay node that maintains the strong connection state of the entire node can be disconnected.

[0088] FIG. 14 is a diagram showing a method for configuring a wireless mesh network according to another embodiment of the present invention, FIG. 15 is a flowchart showing a process of calculating a connection factor in a wireless mesh network configuration method according to another embodiment of the present invention, FIG. 16 is a flowchart showing a process of selecting a relay node in a wireless mesh network configuration method according to another embodiment of the present invention, and FIG. 17 is a diagram showing a process of releasing an unnecessary relay node in a wireless mesh network configuration method according to another embodiment of the present invention.

[0089] Referring to FIGS. 14 to 17, a wireless mesh network configuration method according to another embodiment of the present invention may include the step of calculating network configuration information of a node (S210), the step of selecting a relay candidate node among a plurality of nodes (S220), the step of calculating a connection factor of a node (S230), the step of selecting a relay node among a plurality of nodes (S240), and the step of releasing an unnecessary relay node among the selected relay nodes (S250).

[0090] At this time, a wireless mesh network configured according to another embodiment of the present invention can satisfy the number of exclusive paths composed only of non-overlapping nodes so as to have the desired fault tolerance.

[0091] The step of selecting a relay candidate node among a plurality of nodes (S220) may include the step of selecting a fixed node, in which the packet forwarding function is always turned on, as a relay candidate node, and the step of selecting a variable node, in which the packet forwarding function can be turned on and off, as a relay candidate node.

[0092] In this case, since the fixed node always has its packet forwarding function turned on, it is definitively a relay node. However, if the fixed node is selected as a relay node in advance, a situation may arise where the number of exclusive paths in the network is smaller than the minimum number of exclusive paths, even if all nodes correspond to the strongly connected nodes described later.

[0093] For this reason, in the step of selecting relay nodes (S240), the relay node selection process is carried out by treating fixed nodes as variable nodes.

[0094] Additionally, the step of calculating the connection factor of a node (S230) can calculate the connection factor of a selected relay candidate node, and the connection factor can be calculated based on the node's connection score, the relay degree which is the number of adjacent relay nodes, and the degree which is the number of adjacent nodes, and the connection score can be calculated based on the number of exclusive paths and the relay degree.

[0095] Specifically, the step of calculating the connection factor of a node (S230) may include the step of inputting network configuration information (S231). In this case, the network configuration information may include the location of each node and whether communication with other nodes is possible.

[0096] Additionally, the step of calculating the connectivity factor of a node (S230) may include a step of determining whether there is an adjacent weakly connected node (S232). In this case, if there is an adjacent weakly connected node, the connectivity factor may be calculated (S233) based on the connection score, relay order, and order, and the connectivity factor may be output (S235). Additionally, if there is no adjacent weakly connected node, it may be determined that there is no connectivity factor (S234) and the connectivity factor may be output (S235).

[0097] In addition, the linkage factor can be calculated using the following mathematical formula 2.

[0098] [Mathematical Formula 2]

[0099]

[0100] At this time, F c represents the connection factor, and s represents the connection score. Also, r represents the relay degree, d represents the degree, and N represents the total number of nodes.

[0101] Here, if the connection score s is 0, it means there are no weakly connected nodes and it is excluded from relay candidate nodes, so s > 0 is satisfied. Also, since the degree d can be greater than or equal to the relay degree r and the relay degree r can be greater than or equal to 0, d ≥ r ≥ 0 is satisfied. In this case, the degree d is less than or equal to the total number of nodes N, and if it is 0, it means an independent node not connected to the network, so N ≥ d > 0 is satisfied.

[0102] Additionally, for the connection score, the relay degree of adjacent nodes can be calculated, and the difference between the relay degree of adjacent nodes and the minimum exclusive path number for nodes among the adjacent nodes whose respective relay degrees are smaller than the minimum exclusive path number required to achieve the target fault tolerance can be used as the sum.

[0103] That is, the connection score can be expressed as the sum of the difference between the minimum exclusive path number of weakly connected nodes among adjacent nodes and the relay degree, and can be calculated using the following mathematical formula 1.

[0104] [Mathematical Formula 1]

[0105]

[0106] Here, s is the connection score, E is the minimum exclusive path number, and r i represents the relay degree of an adjacent node that is a weakly connected node.

[0107] Meanwhile, the step of selecting a relay node (S240) may include the step of changing a relay candidate node into a relay node based on the connection score of the relay candidate node, the relay order which is the number of adjacent relay nodes, and the order which is the number of adjacent nodes.

[0108] Specifically, the step of selecting a relay node (S240) may include the step of inputting network configuration information (S221). In this case, the network configuration information may include the location of each node and whether communication with other nodes is possible.

[0109] Additionally, the step of selecting a relay node (S240) may include the step of inputting the connection factor of a relay candidate node (S242).

[0110] At this time, the step of selecting a relay node (S240) may include a step of excluding a relay candidate node from the relay candidate node if the relay candidate node has no connection factor.

[0111] Additionally, the step of changing a relay candidate node into a relay node may involve determining whether all nodes are strongly connected nodes (S243), and if they are strongly connected nodes, changing the fixed node into a relay node (S247) and then terminating the step. Here, a strongly connected node refers to a node whose relay degree is greater than or equal to the minimum exclusive path number.

[0112] Additionally, if there is a weakly connected node among all nodes, it is determined whether there is a relay candidate node (S244), and if there is no relay candidate node, the fixed node is changed to a relay node (S247) and the step can be terminated. Here, a weakly connected node refers to a node whose relay degree is less than the minimum exclusive path number.

[0113] In addition, if there are relay candidate nodes, the node with the largest connection factor among the relay candidate nodes can be changed to the relay node (S245).

[0114] Meanwhile, during the step of changing relay candidate nodes into relay nodes, if there is a strongly connected node among the relay candidate nodes, it can be changed into a relay node preferentially. In this case, the relay node can be determined based on the connection score, relay degree, and degree of each strongly connected node.

[0115] Specifically, if there is a strongly connected node among the relay candidate nodes, the strongly connected node with the largest relay node connection factor can be changed to the relay node by comparing the connection factors of the strongly connected nodes.

[0116] In addition, in the step of selecting the relay node, if there is no strongly connected node among the relay candidate nodes, the relay node can be determined based on the connection factor of the weakly connected node with the largest relay degree among the weakly connected nodes with a relay degree less than the minimum exclusive path number.

[0117] Specifically, if there are no strongly connected nodes among the relay candidate nodes, the relay degrees of the weakly connected nodes can be compared, and the node with the highest relay degree can be changed to the relay node. As a result, a partially strongly connected network composed of nodes satisfying the minimum exclusive path number can be quickly constructed.

[0118] In this case, if there are two or more nodes with the highest relay degree, the connection factors of the nodes with the highest relay degree can be compared, and the node with the largest connection factor among them can be changed to the relay node.

[0119] Subsequently, when a relay node is determined, the method may include a step (S246) of updating information on the changed node and adjacent nodes. At this time, the information of the node may include at least one of whether it is a strongly connected node, a connection factor, a connection score, and a relay degree.

[0120] The step of changing a relay candidate node to a relay node can be performed repeatedly after the step of updating information on the changed node and adjacent nodes (S246), returning to the step of determining whether the entire node is a strongly connected node (S243), until the entire node is a strongly connected node or there are no relay candidate nodes.

[0121] Meanwhile, the step of releasing unnecessary relay nodes among the selected relay nodes (S250) may include the step of selecting a relay node as a relay release candidate node, the step of determining whether to release a node after selecting one of the relay release candidate nodes, and the step of releasing the relay release candidate node from the relay nodes according to the determination.

[0122] Specifically, the step of releasing unnecessary relay nodes among the relay nodes (S250) may include the step of inputting network configuration information (S251) and the step of selecting variable nodes among the relay nodes as relay release candidate nodes (S252).

[0123] Additionally, in the step of determining whether to disconnect after selecting one of the relay disconnection candidate nodes, it is determined whether there is a relay disconnection candidate node (S253), and if there is a relay disconnection candidate node, the node with the largest disconnection factor can be selected first (S254).

[0124] At this time, the disconnection factor can be calculated based on the relay order and order of the node. In addition, the disconnection factor can be calculated using the following mathematical formula 3.

[0125] [Mathematical Formula 3]

[0126]

[0127] At this time, F dc is the disconnection factor, and r represents the relay degree. Also, d represents the degree, and N represents the total number of nodes.

[0128] Here, the degree d can be greater than or equal to the relay degree r, and since the relay degree r can be greater than or equal to 0, d ≥ r ≥ 0 is satisfied. In this case, the degree d is less than or equal to the total number of nodes N, and if it is 0, it means an independent node not connected to the network, so N ≥ d > 0 is satisfied.

[0129] Afterwards, it can be determined whether the entire node maintains a strongly connected node state even if the selected relay release candidate node is released (S255), and if the entire node maintains a strongly connected node state even if the selected relay release candidate node is released, the selected relay node can be released (S256).

[0130] Subsequently, when a relay release candidate node is released, the method may include a step (S257) of updating information about the released node and adjacent nodes. At this time, the information of the node may include at least one of whether it is a strongly connected node, a connection score, a relay order, and an order.

[0131] After selecting one of the relay release candidate nodes, the step of determining whether to release and the step of releasing the relay release candidate node from the relay node according to the determination can be performed repeatedly until there are no relay release candidate nodes, by performing the step of updating information of the released node and adjacent nodes (S257) and returning to the step of determining whether there are relay release candidate nodes (S253).

[0132] Additionally, in the step (S255) of determining whether the entire node maintains a strongly connected node state even if the selected relay release candidate node is released, if it is determined that the entire node does not maintain a strongly connected node state when the selected relay release candidate node is released, the selected relay release candidate node is changed to a relay node (S258), and then the process can be repeated by returning to the step (S253) of determining whether there is a relay release candidate node until there is no relay release candidate node.

[0133] The preferred embodiments of the present invention described above are disclosed for illustrative purposes only, and various modifications and variations of the technical concept of the present invention are possible by those skilled in the art to which the present invention pertains, and such modifications and variations will fall within the scope of protection of the present invention.

Claims

1. A method for configuring a fault-tolerant wireless mesh network by selecting a relay node that transmits packets among a plurality of nodes, Step of calculating the network configuration information of the node; A step of selecting a relay node among a plurality of nodes; and It includes a step of releasing unnecessary relay nodes among the selected relay nodes, and A wireless mesh network configuration method that satisfies the number of exclusive paths composed only of non-overlapping nodes so as to have the desired fault tolerance.

2. In Paragraph 1, The step of selecting the above relay node is, A step of selecting a relay candidate node among the plurality of nodes above; and The method includes the step of changing a relay candidate node into a relay node based on the connection score of the above relay candidate node, the relay order which is the number of adjacent relay nodes, and the order which is the number of adjacent nodes. A wireless mesh network configuration method that calculates the above connection score based on the number of exclusive paths and the relay order.

3. In Paragraph 2, The step of changing the above relay candidate node into a relay node is, A wireless mesh network configuration method that calculates the relay order of adjacent nodes, calculates the difference between the relay order of a node among the adjacent nodes that has a relay order smaller than the minimum exclusive path number required to achieve the target fault tolerance, and adds the result to use as the connection score.

4. In Paragraph 3, A wireless mesh network configuration method in which the above connection score is calculated using the following mathematical formula 1. [Mathematical Formula 1] (s: connectivity score, E: minimum exclusive path number, r i : Relay degree of adjacent nodes) 5. In Paragraph 3, In the step of changing the above relay candidate node into a relay node, A wireless mesh network configuration method that prioritizes changing to a relay node when there is a strongly connected node with a relay order greater than or equal to the minimum exclusive path number.

6. In Paragraph 5, In the step of changing the above relay candidate node into a relay node, A wireless mesh network configuration method for determining relay nodes based on the connection score, relay order, and order of each strongly connected node when there are strongly connected nodes among relay candidate nodes.

7. In Paragraph 5, In the step of changing the above relay candidate node into a relay node, A wireless mesh network configuration method for determining relay nodes based on the connection score, relay order, and order of each weakly connected node, where there are no strongly connected nodes among the relay candidate nodes, and where the relay order is less than the minimum exclusive path number.

8. In Paragraph 7, In the step of changing the above relay candidate node into a relay node, A wireless mesh network configuration method for determining relay nodes based on the connection score and degree of the weakly connected node with the largest relay degree among weakly connected nodes when there are no strongly connected nodes among relay candidate nodes.

9. In any one of paragraphs 6 through 8, In the step of changing the above relay candidate node into a relay node, Whenever a relay candidate node changes to a relay node, update the information of the changed node and adjacent nodes, and The above information is a wireless mesh network configuration method including at least one of whether the node is strongly connected, the connection score, and the relay order.

10. In Paragraph 9, A wireless mesh network configuration method in which the step of changing the above relay candidate nodes into relay nodes is repeated until all nodes are changed into strongly connected nodes or until there are no remaining relay candidate nodes.

11. In Paragraph 10, The step of selecting the above relay candidate node is a wireless mesh network configuration method in which a fixed node with a packet forwarding function always turned on is selected as a relay candidate node.

12. In Paragraph 11, The step of selecting the above relay candidate node is a wireless mesh network configuration method in which a variable node capable of turning the packet forwarding function on and off is selected as the relay candidate node.

13. In Paragraph 12, In the step of changing the above relay candidate node into a relay node, A wireless mesh network configuration method in which fixed nodes are changed to relay nodes when all nodes are changed to strongly connected nodes or when the remaining relay candidate nodes are eliminated.

14. In Paragraph 13, The step of releasing the above unnecessary relay node is, A step of selecting the above relay node as a candidate node for relay release; A step of selecting one of the above relay release candidate nodes and determining whether to release it; and A wireless mesh network configuration method comprising the step of releasing a relay release candidate node from the relay node based on the above judgment.

15. In Paragraph 14, The step of selecting the above relay node as a relay release candidate node is a wireless mesh network configuration method in which a variable node among the relay nodes is selected as a relay release candidate node.

16. In Paragraph 15, After selecting one of the aforementioned relay release candidate nodes, in the step of determining whether to release it, A wireless mesh network configuration method for determining to release a relay node when all nodes maintain a strongly connected node state even if the selected node is released.

17. In Paragraph 16, After selecting one of the aforementioned relay release candidate nodes, in the step of determining whether to release it, A wireless mesh network configuration method that selects nodes starting from the smallest relay order.

18. In Paragraph 17, After selecting one of the aforementioned relay release candidate nodes, in the step of determining whether to release it, A wireless mesh network configuration method in which, when there are two or more nodes with the smallest relay degree, the node with the smallest degree is selected first.

19. In Paragraph 16, In the step of releasing a relay release candidate node from the relay node based on the above judgment, Whenever a relay release candidate node is released, update the information of the released node and adjacent nodes, and The above information is a wireless mesh network configuration method including at least one of whether the node is strongly connected, the connection score, the relay order, and the order.

20. In Paragraph 1, A wireless mesh network configuration method in which the above network configuration information includes the location of a node and whether communication with other nodes is possible.

21. A method for configuring a fault-tolerant wireless mesh network by selecting a relay node that transmits packets among a plurality of nodes, Step of calculating the network configuration information of the node; Step of calculating the node's connectivity factor; A step of selecting a relay node among a plurality of nodes; and It includes a step of releasing unnecessary relay nodes among the selected relay nodes, and The above wireless mesh network satisfies the number of exclusive paths composed only of non-overlapping nodes to have the desired fault tolerance, and The above connection factor is calculated based on the node's connection score, the relay degree which is the number of adjacent relay nodes, and the degree which is the number of adjacent nodes, and A wireless mesh network configuration method that calculates the above connection score based on the number of exclusive paths and the relay order.

22. In Paragraph 21, It further includes a step of selecting relay candidate nodes among multiple nodes, and The step of calculating the above connection factor calculates the connection factor of the selected relay candidate node, and The step of selecting the above relay node is a wireless mesh network configuration method that selects and changes a relay candidate node as a relay node.

23. In Paragraph 22, A wireless mesh network configuration method in which the above connection factor is calculated using the following mathematical formula 2. [Mathematical Formula 2] (F c : Connection factor, s: Connection score, r: Relay degree, d: Degree, N: Total number of nodes) 24. In Paragraph 23, The step of calculating the above linkage factor is, A wireless mesh network configuration method that calculates the relay order of adjacent nodes, calculates the difference between the relay order of a node among the adjacent nodes that has a relay order smaller than the minimum exclusive path number required to achieve the target fault tolerance, and adds the result to use as the connection score.

25. In Paragraph 24, A wireless mesh network configuration method in which the above connection score is calculated using the following mathematical formula 1. [Mathematical Formula 1] (s: connectivity score, E: minimum exclusive path number, r i : Relay degree of adjacent nodes) 26. In Paragraph 24, In the step of selecting the above relay node, A wireless mesh network configuration method that prioritizes changing to a relay node when there is a strongly connected node with a relay order greater than or equal to the minimum exclusive path number.

27. In Paragraph 26, In the step of selecting the above relay node, A wireless mesh network configuration method in which, when there are strongly connected nodes among the relay candidate nodes, the node with the largest connection factor among the strongly connected nodes is selected as the relay node.

28. In Paragraph 26, In the step of selecting the above relay node, A wireless mesh network configuration method for determining a relay node based on the connection factor of the weakly connected node with the largest relay degree among weakly connected nodes with a relay degree less than the minimum exclusive path number, when there is no strongly connected node among the relay candidate nodes.

29. In Paragraph 28, In the step of selecting the above relay node, A wireless mesh network configuration method in which, when there are no strongly connected nodes among the relay candidate nodes, the node with the largest connection factor among the weakly connected nodes with the largest relay degree is changed to the relay node.

30. In any one of paragraphs 27 through 29, In the step of calculating the connection factor of the above node, A wireless mesh network configuration method in which the connection factor is considered non-existent when there are no weakly connected nodes adjacent to the corresponding node.

31. In Paragraph 30, In the step of selecting the above relay node, A wireless mesh network configuration method that excludes a relay candidate node from a relay candidate node when the above relay candidate node has no connection factor.

32. In Paragraph 31, In the step of selecting the above relay node, Whenever a relay candidate node changes to a relay node, update the information of the changed node and adjacent nodes, and The above information is a wireless mesh network configuration method including at least one of whether the node is strongly connected, a connection factor, a connection score, and a relay order.

33. In Paragraph 32, A wireless mesh network configuration method in which the above relay selection step is repeated until all nodes are changed to strongly connected nodes or until there are no remaining relay candidate nodes.

34. In Paragraph 33, The step of selecting the above relay candidate node is a wireless mesh network configuration method in which a fixed node with a packet forwarding function always turned on is selected as a relay candidate node.

35. In Paragraph 34, The step of selecting the above relay candidate node is a wireless mesh network configuration method in which a variable node capable of turning the packet forwarding function on and off is selected as the relay candidate node.

36. In Paragraph 35, In the step of changing the above relay candidate node into a relay node, A wireless mesh network configuration method in which fixed nodes are changed to relay nodes when all nodes are changed to strongly connected nodes or when the remaining relay candidate nodes are eliminated.

37. In Paragraph 36, The step of releasing the above unnecessary relay node is, A step of selecting the above relay node as a candidate node for relay release; A step of selecting one of the above relay release candidate nodes and determining whether to release it; and A wireless mesh network configuration method comprising the step of releasing a relay release candidate node from the relay node based on the above judgment.

38. In Paragraph 37, The step of selecting the above relay node as a relay release candidate node is a wireless mesh network configuration method in which a variable node among the relay nodes is selected as a relay release candidate node.

39. In Paragraph 38, After selecting one of the aforementioned relay release candidate nodes, in the step of determining whether to release it, A wireless mesh network configuration method for determining to release a relay node when all nodes maintain a strongly connected node state even if the selected node is released.

40. In Paragraph 39, After selecting one of the aforementioned relay release candidate nodes, in the step of determining whether to release it, Among the above relay release candidate nodes, select the node with the largest disconnection factor, and A wireless mesh network configuration method in which the above disconnection factor is calculated based on the relay order and order of the node.

41. In Paragraph 40, A wireless mesh network configuration method in which the above disconnection factor is calculated using the following mathematical formula 3. [Mathematical Formula 3] (F dc : Disconnection parameter, r: Relay degree, d: Degree, N: Total number of nodes) 42. In Paragraph 39, In the step of releasing a relay release candidate node from the relay node based on the above judgment, Whenever a relay release candidate node is released, update the information of the released node and adjacent nodes, and The above information is a wireless mesh network configuration method including at least one of whether the node is strongly connected, the connection score, the relay order, and the order.

43. In Paragraph 21, A wireless mesh network configuration method in which the above network configuration information includes the location of a node and whether communication with other nodes is possible.

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