KR20100030892A - Re-routing method for node failure in tactical wireless mesh network - Google Patents

Abstract

PURPOSE: A re-routing method in a wireless mesh network is provided to detour only part of a route with a problem in the wireless mesh network, thereby locally resetting a call without resetting the entire route. CONSTITUTION: It is determined whether node failure occurs(401). Existing routes passing nodes with failure are reset due to the nodes with failure using a communicable node(402). Remaining existing routes passing the nodes with failure are reset using a detour route to the next node of the node with failure(403).

Description

RE-ROUTING METHOD FOR NODE FAILURE IN TACTICAL WIRELESS MESH NETWORK}

The present invention relates to a rerouting method in a wireless mesh network whose configuration is dynamically changed, and to a computer-readable recording medium recording a program for realizing the method. More particularly, the present invention relates to a current path in a wireless mesh network. In order to resume communication service even if a part of the node disappears or becomes unavailable, it is possible to use the local information only through the node without resetting the entire end-to-end call. The present invention relates to a rerouting method in a wireless mesh network and a computer readable recording medium having recorded thereon a program for realizing the method.

In general, wireless LANs have a limited service area and communication quality due to the use of a low power unlicensed band. The wireless mesh technology newly introduced to overcome the limitations of the WLAN is a wireless mesh network technology. This wireless mesh network technology is expected to play an important role as the next generation low power wireless technology for ubiquitous implementation.

In the existing WLAN, a plurality of computers are connected around one access point (AP) to form a network in a point-to-point or point-to-multipoint manner. However, in wireless mesh networks, devices with wireless functions communicate with each other to increase network reliability and to enable expansion with less power.

In this environment, a WLAN access point (AP) requires self configuration and self management for reliable transmission and automatic routing between mesh links.

Meanwhile, in May 2004, the Working Groups (TGs) meeting of "IEEE 802.11" defined the usage model and terminology for the development of network technology standards and agreed on technical contributions to related technologies. At the same time, "IEEE 802.15 TG5" was also formed for the PAR (Project Authorization Request) work and the five standards. Accordingly, technical standardization is currently being performed in the workgroups (TGs) of "IEEE 802.11" and network standardization in "IEEE 802.15 TG5".

However, in the existing wireless mesh network, when a part of the node (or link) constituting the current path disappears or becomes incapable of communication, it is necessary to reconfigure the entire path through the entire end-to-end call resetting. There was a problem.

In other words, in the existing wireless mesh network, if some nodes forming the mesh network disappear or become incapable of communication, if there is a call using the node, the end-to-end path must be reset for the call. There was a problem.

That is, the prior art as described above has a problem in that the entire path must be newly reset when some nodes constituting the current path disappear or become incapable of communication, and it is an object of the present invention to solve such a problem.

Accordingly, the present invention provides a method and a method for resetting a path in a wireless mesh network to enable communication service by resetting a local call without resetting the entire path by bypassing a path having some problem in the wireless mesh network. Its purpose is to provide a computer readable recording medium having recorded thereon a program.

That is, in the present invention, when a part of the nodes constituting the current path in the wireless mesh network disappears or becomes impossible to communicate, the present invention uses only local information without using end-to-end call resetting. In order to provide a communication service by resetting communication paths communicating via a network, a method for resetting a path in a wireless mesh network and a computer-readable recording medium recording a program for realizing the method are provided. The purpose is.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned above can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

In accordance with another aspect of the present invention, a method for rerouting includes: checking whether a node failure has occurred; A primary path resetting step of resetting existing paths that have passed through the failed node by using the communicable node caused by the failed node; And a second path resetting step of resetting existing paths that have passed through the failing node remaining after performing the first path resetting step by using a detour path of the failed node to a next node.

In addition, the method of the present invention uses an end-to-end rerouting, tertiary rerouting to reestablish existing paths that passed through the failed node remaining after performing the secondary rerouting step. It further comprises a step.

On the other hand, the present invention, a path resetting device having a processor, a function for checking whether a node failure has occurred; A primary path resetting function for resetting existing paths that have passed through the failing node by using the communicable node caused by the failing node; And a program for realizing a secondary path reset function for resetting existing paths that have passed through the failed node remaining after performing the primary path reset function, by using a detour path to the next node of the failed node. It includes a computer readable recording medium.

In addition, the present invention further provides a tertiary rerouting function of resetting existing paths that have passed through the failed node remaining after the secondary rerouting function, using end-to-end rerouting. A computer readable recording medium having recorded thereon a program for realization is provided.

In the present invention as described above, it is possible to bypass only some problematic paths in the wireless mesh network so as to enable communication service by locally resetting the call without resetting the entire path.

That is, according to the present invention, when a node constituting a mesh network in the existing wireless mesh network disappears or becomes incapable of communication, if there is a call using the node, the present invention is end-to-end with respect to the call. Instead of rerouting, by providing a method that enables rerouting locally, there is an effect of overcoming communication failures in a shorter time.

The above objects, features, and advantages will become more apparent from the detailed description given hereinafter with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention pertains may share the technical idea of the present invention. It will be easy to implement. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

First, to briefly explain the technical gist of the present invention to assist in understanding the present invention.

When a problem occurs in a path of a wireless mesh network (for example, when some nodes constituting the current path disappear or become incapable of communication), routing may be performed by selecting one of the following two methods. .

The first approach is to return to the departure node and re-routing. The second approach is to bypass the faulted node locally.

Here, the first scheme can set a more globally optimized route than the second local bypass method, but it has a disadvantage in that the time taken for routing is increased.

Accordingly, in the present invention, when a problem occurs in some nodes or links in a wireless mesh network, the present invention intends to be able to continue communication by using the second bypass local rerouting scheme.

To this end, each node of the wireless mesh network manages a neighbor list including propagation environment information about neighbor base stations.

On the other hand, as described above, if some of the nodes that are currently communicating during communication disappears, it is necessary to reset the communication path. In general, from the viewpoint of the current node, adjacent nodes act as interference with each other. Thus, if some of the neighboring nodes are lost, the radio link between the current base station and other neighboring base stations will result in an improvement in signal to noise ratio. As a result, communication with neighboring nodes, which has not been previously possible, may be possible.

Therefore, when some nodes of the currently connected nodes disappear, the signal-to-noise ratio is recalculated for all signals that can be received by the current node, and a new connection is made with the nodes that are newly able to communicate according to the recalculated signal-to-noise ratio. Thereafter, the path of the calls established via the missing node is reset through the newly connected links to the current node.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a configuration of a wireless mesh network before the node F disappears, FIG. 2 is a diagram illustrating a configuration of the wireless mesh network after the node F disappears, and FIGS. 3A and 3B are neighbor lists of the node B. ) Is an example diagram.

In FIG. 1, when there is a node F, the neighbor node list of the node B that becomes the current node is as shown in FIG. 3A.

On the other hand, when the node F disappears, when the link between the nodes is changed as shown in FIG. 2, the neighbor node list at the node B which becomes the current node is changed as shown in FIG. 3B.

Meanwhile, a specific rerouting method for the case of basic node loss is as shown in FIGS. 4 and 5A and 5B, and is installed and executed in the current node of the wireless mesh network as an example.

The following terms are defined to clarify the following description.

1) The current node, which is the node on which the rerouting method proposed in the present invention is performed: Φ

2) Missing Nodes Considered in the Invention: A _F

3) A set of adjacent nodes that are adjacent to the current node and have a direct connection with the current node: A = {A ₁ , A ₂ , A ₃ , ..., A _M }

4) A collection of nodes that have a direct connection with an adjacent node A ₁ :

이다.At this time,

to be.

And look at the conditions according to the invention as follows.

1) Each node Φ can be connected to a single or a plurality of unlimited numbers of adjacent nodes A _X.

를 호 설정 시에 저장하고 있다.2) Each node Φ is the overall initial path information for the call established via that node.

Is stored during call setup.

3) Each node Φ stores information about directly connected nodes D _X for each directly connected adjacent node A _X.

4) Each node Φ sends an updated direct connection node list A to neighbor nodes A _X when the direct connection is added or deleted.

의 설정 방식에 대해 별도로 동작한다고 가정하며, 의존적이지 않다. 그러나 설명의 편의를 위해 초기 경로는 항상 최적의 경로로 설정된다고 가정한다.5) The present invention is the initial route information

It is assumed to operate separately for the configuration method of, and is not dependent. However, for convenience of explanation, it is assumed that the initial path is always set to the optimal path.

4 is a flowchart illustrating a rerouting method in a wireless mesh network according to the present invention.

First, it is checked whether there is a node that disappears or becomes unable to communicate among neighboring nodes directly connected (401). In other words, it is checked whether a node failure occurs due to a node disappearing from a node or a link that has become part of a mesh network in a wireless mesh network.

As a result of the check 401, if there is no node that disappears or communication becomes impossible among the directly connected neighbor nodes, the check process 401 is repeatedly performed while performing the basic operation, and disappears or communication is not possible among the directly connected neighbor nodes. If there is a node that has been made, the existing paths that have passed through the disappeared node are reset by using nodes that are newly able to communicate due to node change (eg, node disappearance) of the wireless mesh network (402). That is, existing paths that have passed through the failed node are reset using the communicable node caused by the failed node (primary path reset).

After the primary path resetting, if existing paths that have passed through the lost node that have not yet been reset remain, they are reset using the detour path to the next node that disappeared (403). That is, the remaining path remaining after the first path resetting among the existing paths passing through the failing node is reset by using the detour path to the next node of the failing node (secondary path resetting).

After the secondary path reset, if there are existing paths that have passed through the lost node that have not yet been reset, the end-to-end path reset is used to reset (404). That is, an end-to-end path reset is used to reset the remaining path remaining after the second path reset among the existing paths passing through the failed node (tertiary path reset).

5A and 5B are detailed flowcharts of an embodiment of a rerouting method in a wireless mesh network according to the present invention.

First, it is checked whether there is a node that disappears or cannot communicate among adjacent nodes directly connected to the current node (501). In other words, it is checked whether a node failure occurs due to a node disappearing from a node or a link that has become part of a mesh network in a wireless mesh network.

As a result of the check 501, if there is no node that disappears or communication becomes impossible among the directly connected neighbor nodes, the checking process 501 is repeatedly performed while performing a basic operation, and disappears or communication is not possible among the directly connected neighbor nodes. If there is a node, proceed to "502" to start automatic network recovery.

That is, the signal-to-noise ratio is recalculated for all signals receivable at the current node (502).

Thereafter, a direct connection is established with nodes newly enabled for communication due to a node change (eg, a node disappears) of the wireless mesh network (503).

Thereafter, after updating the direct connection list A of the current node to include the new direct connection nodes, the updated direct connection list information of the current node is transmitted to each directly connected node A _X (504).

가 있는지를 확인한다(505).Later, arcs in the path contain node A _F lost during the existing connection.

Check whether there is (505).

의 삭제된 노드 A_F 이후의 경로에 직접 연결 리스트 A의 노드들이 포함되는지 확인한다(506).As a result of the check 505, if there is no call including the node disappeared during the existing connection in the path, the process proceeds to step 501 and repeats, and if there is a call including the node disappeared during the existing connection in the path, the original path information

It is checked whether the path after the deleted node A _F of the node includes the nodes of the direct connection list A (506).

에서 사라진 노드를 삭제하고, 경로가 현재 노드 Φ에서 연결 리스트 A의 노드로 바로 연결되도 록 경로 정보를 재조정하고, 해당 호의 새로운 경로를 따라 호 설정을 다시하고, 동시에 해당 호의 업데이트된 경로 정보를 업데이트한 후에(507) "505" 과정으로 진행한다. 이때, 사라진 노드 A_F외에도 경로에서 빠진 노드가 있다면, 이러한 노드에는 신호를 보내 자원을 반납하도록 한다. 이때, 새 경로를 구성하는 노드 수는 기존의 경로의 노드 수 이하가 되므로, 데이터 레이트(Data Rate)와 딜레이(Delay) 같은 서비스 품질(QoS)은 최소한 기존 경로 이하가 된다. 따라서 이 경우에는 경로의 서비스 품질(QoS)에 대한 확인 절차 없이 바로 해당 경로를 연결하여 사용 가능하다.As a result of the check 506, if there are nodes included in the path after the deleted node of the original path information among the nodes in the direct connection list, the path of the corresponding call

Deletes the missing node, rebalances the path information so that the path connects directly from node Φ to the node in connection list A, redefines the call setting along the new path of the arc, and simultaneously updates the updated path information of the arc. After step 507, the process proceeds to "505". At this time, if there is a node missing from the path in addition to the missing node A _F , the node is signaled to return resources. At this time, since the number of nodes constituting the new path is less than or equal to the number of nodes of the existing path, quality of service (QoS) such as data rate and delay is at least less than the existing path. Therefore, in this case, the path can be connected and used immediately without checking the quality of service (QoS) of the path.

As a result of the check 506, if there are no nodes included in the path after the deleted node of the original path information among the nodes in the direct connection list, the node disappears on the path among the nodes A _X currently connected to the node. In addition to node A _F , check whether there is a direct connection with the node following A _F (508). That is, check whether there is a node directly connected to the next node of the missing node on the path of the corresponding node among the nodes connected to the current node.

를 재설정하고, 경로 정보를 재조정한 후에(509) "505" 과정으로 진행한다. 이때, 호를 재설정하기 전에 해당 호의 서비스 품질(QoS) 요구사항을 살펴, 새로운 경로 설정으로 인해 변경된 서비스 품질(QoS)이 해당 호의 서비 스 품질(QoS)을 만족시키는지 확인해야 한다.As a result of the check 508, among the nodes connected to the current node, if there is a node directly connected to the next node of the missing node on the path of the corresponding path, the node and the path instead of the disappeared node

After re-establishing and reorienting the route information (509), the process proceeds to "505". At this time, before resetting the call, the quality of service (QoS) requirements of the call should be examined to confirm that the changed quality of service (QoS) meets the quality of service (QoS) of the call.

As a result of the check 508, among the nodes connected to the current node, if there is no node directly connected to the next node of the missing node on the path of the corresponding path, the local call setup at the node Φ is abandoned, and the new end-to-end After the end-to-end call is requested (510), the process proceeds to "505".

On the other hand, the method of the present invention as described above can be written in a computer program. And the code and code segments constituting the program can be easily inferred by a computer programmer in the art. In addition, the written program is stored in a computer-readable recording medium (information storage medium), and read and executed by a computer to implement the method of the present invention. The recording medium may include any type of computer readable recording medium.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention can be used for communication through a wireless mesh network and the like.

1 is an exemplary configuration diagram of a wireless mesh network before the node F disappears.

2 is an exemplary configuration diagram of a wireless mesh network after node F disappears.

3A and 3B are exemplary diagrams of a neighbor list at a node B;

4 is a flowchart illustrating a rerouting method in a wireless mesh network according to the present invention;

5A and 5B are detailed flowcharts of an embodiment of a rerouting method in a wireless mesh network according to the present invention.

Claims (5)

In the rerouting method, Identifying whether a node failure has occurred; A primary path resetting step of resetting existing paths that have passed through the failed node by using the communicable node caused by the failed node; And A second path resetting step of resetting existing paths that have passed through the failed node remaining after the first path resetting step is performed by using a detour path to the next node of the failed node; Rerouting method comprising a. The method of claim 1, Tertiary rerouting step using end-to-end rerouting to re-establish existing paths through the failed node that remain after the secondary rerouting step Path reset method further comprising. The method according to claim 1 or 2, The primary path resetting step, Recalculating a signal-to-noise ratio for the signal received at the current node; Establishing a direct connection with the newly enabled nodes due to the node change according to the failed node; Updating a direct connection list of the current node to include new direct connection nodes for which the direct connection is established; And Transmitting direct connection list information of the current node to each directly connected node; Rerouting method comprising a. In a rerouting device having a processor, Identifying whether a node failure has occurred; A primary path resetting function for resetting existing paths that have passed through the failing node by using the communicable node caused by the failing node; And Secondary path resetting function for resetting existing paths that have passed through the failed node remaining after the primary path resetting function, by using the detour path to the next node of the failed node. A computer-readable recording medium having recorded thereon a program for realizing this. The method of claim 4, wherein Tertiary rerouting function, which uses the end-to-end rerouting to re-establish existing paths through the failed node remaining after performing the secondary rerouting function. A computer-readable recording medium that records a program for further realization.

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