KR101107326B1 - Method for finding and reporting neighbor node in a sensor network - Google Patents

Abstract

The present invention relates to a method for discovering and reporting neighboring nodes in a sensor network, the method comprising: forming a tree topology for the sensor network; Collecting neighbor node information from each node of the tree topology and delivering the neighbor node information to the sink node through a routing path; Sequentially rescanning the tree topology to find and add missing nodes to the tree topology; And transmitting the information of the missing node to the sink node in the node that has found the missing node, thereby enabling the collection of more efficient and reliable neighbor node information in the sensor network.

Collect neighbor node information, find missing nodes, add missing nodes, form tree topology

Description

Method for finding and reporting neighbor node in a sensor network

The present invention relates to a method for discovering and reporting neighboring nodes in a sensor network, and more particularly, to a method for discovering and reporting neighboring nodes in a sensor network to prevent the occurrence of missing nodes.

The sensor network is generally composed of sink nodes and sensor nodes, and the routing process from sensor node to sink node is well known and tree routing (for example, Standard Route, MintRoute, It is performed based on Reliable Route.

The general routing process of tree routing is as follows.

First, nodes constituting the sensor network periodically broadcast a HELLO message. Nodes adjacent to the sink node receive and respond to messages broadcast from the sink node, selecting the sink node as the parent node, and in the next period, neighboring nodes of the sink node become parent nodes of other nodes by broadcasting a HELLO message. .

By repeating this process, all nodes in the sensor network select their own parent node and connect to the parent node, thereby establishing a path to the sink node.

Meanwhile, the sink node of the sensor network should acquire and maintain neighbor node information for the entire sensor network. This is because it is necessary to control and manage scheduling at the sink node for more efficient management when using MAC or beacon based on Time Division Multiple Access (TDMA). This is because neighboring node information may be needed.

In the related art, each node collects its own neighbor node information and then provides it to the sink node using the path (i.e., tree routing path) established through the above process, and the sink node receives and aggregates the entire sensor network. It was possible to obtain neighbor node information for.

However, since the routing process of tree routing according to the prior art does not provide a function for detecting and adding missing nodes, the mode node constituting the sensor network participates in the tree topology or information of all neighbor nodes in each node. There was a problem that can not be guaranteed to collect.

That is, conventionally, even if a missing node occurs, there is a problem in that it cannot be found and added to the tree topology.

Accordingly, the present invention is to provide a method for discovering and reporting neighboring nodes in a sensor network that can apply a tree topology setting process to discover missing nodes and add them to the tree topology.

In addition, by acquiring and reporting the information of the missing node to the sink node, it is to provide a neighbor node discovery and reporting method in the sensor network to enable the sensor network to perform a more accurate and reliable operation.

According to a first aspect of the present invention, as a means for solving the above problems, forming a tree topology for the sensor network; Collecting neighbor node information from each node of the tree topology and delivering the neighbor node information to the sink node through a routing path; Sequentially rescanning the tree topology to find and add missing nodes to the tree topology; And further transmitting information of the missing node to the sink node in the node that finds the missing node.

The forming of the topology may include broadcasting a node discovery request message at each node and receiving a node discovery response message; Analyzing the node discovery response message to obtain neighbor node information; And selecting a node having a minimum hop count from a neighbor node transmitting the node discovery response message to a sink node as a parent node to participate in a tree topology.

The forming of the topology may be performed at each node while sequentially proceeding from the highest level node to the lowest level node.

Preferably, the node discovery request message includes node ID information and node discovery request information, and the node discovery response message includes node ID information.

The transferring to the sink node may include transmitting, by a node located at the lowest level, its neighbor node information to a parent node; A node located at an intermediate level collects neighbor node information transmitted from the child node and its neighbor node information and transmits the neighbor node information to the parent node; And acquiring neighbor node information for the entire sensor network by collecting the neighbor node information transmitted from the child node by the sink node located at the highest level.

In the collecting and delivering the neighbor node information to the parent node, the neighbor node information transmitted from the child node and its neighbor node information are compared with each other, and the overlapping information is merged into one piece of information.

In the collecting and delivering the neighbor node information to the parent node, the neighbor node information transmitted from the child node and its neighbor node information are collected, divided into a plurality of messages, and delivered to the parent node.

Discovering and adding the missing node to the tree topology may include broadcasting a missing node discovery request message at each node; Generating and transmitting a missing node discovery response message and participating in the tree topology, wherein the missing node which has not received the node discovery request message has received the missing node discovery request message; And acquiring the missing node discovery response message by analyzing the missing node discovery response message to obtain information on the missing node.

Preferably, the missing node discovery request message includes node ID information, hop count to sink nodes, and node discovery request information.

The step of finding the missing node and adding it to the tree topology further includes the step of setting the number of hops of the missing node by adding the number of hops to the sink node included in the missing node discovery request message plus "1". It is characterized by including.

Preferably, the missing node discovery response message includes node ID information.

As described above, the method for discovering and reporting neighboring nodes in the sensor network of the present invention forms a tree topology and then discovers the missing node through a missing node rescanning process, and allows the missing node to participate in the tree topology. In addition, by reporting the information of the missing node to the sink node, the sink node can obtain the neighbor node information for the entire sensor network more accurate and reliable.

Accordingly, in the sensor network using the method of the present invention, when central scheduling is necessary or when location recognition is needed, it is possible to efficiently collect and manage neighbor node information on the configuration nodes. In addition, it is possible to construct an efficient and stable sensor network system, to centralize network scheduling of nodes constituting the sensor network, and to collect neighbor node information necessary for applications such as location recognition. It can be applied to application applications that require characteristics.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification.

Also, when a part is referred to as "including " an element, it does not exclude other elements unless specifically stated otherwise.

1 is a diagram schematically illustrating a neighbor node discovery and reporting method in a sensor network according to an embodiment of the present invention.

Referring to FIG. 1, the method for discovering and reporting neighboring nodes in a sensor network according to an embodiment of the present invention may include forming a tree topology for a sensor network (S10), and collecting information about neighboring nodes in each node of the tree topology to establish a routing path. Transfer process (S20) to deliver to the sink node through, the process of finding the missing node and re-adding to the tree topology while sequentially rescanning the tree topology (S30), the information of the missing node in the node found the missing node sink node In addition to the step of delivering (S40).

Hereinafter, each process will be described in more detail individually.

2A to 2D are diagrams for explaining a tree topology forming process S10 according to an embodiment of the present invention in more detail.

The tree topology forming process of the present invention is performed at each node while going sequentially from the highest level to the lowest level over several periods. That is, after the tree topology forming process is first performed by the sink node, in the next cycle, the nodes receiving the node discovery request message of the previous cycle are performed in a manner of performing the topology forming process.

Hereinafter, for convenience of description, the operation in the Node C will be described as an example.

First, as shown in FIG. 2A, the Node C generates a node discovery request message including its ID information and node discovery request information, and broadcasts them to nodes adjacent to the node.

Nodes (for example, nodes A, D, and E) that have received the Node C's Node Discovery Request message generate a Node Discovery Response message containing their identity information to Node C as shown in FIG. 2B. send.

Node C extracts the node ID included in the node discovery response message transmitted from nodes A, D, and E and stores the node ID in the neighbor node information table. That is, the node discovery response message is analyzed to obtain neighbor node information.

Node C selects a node having the minimum number of hops from the neighbor node to the sink node as a parent node and performs a connection to the parent node, and participates in the tree topology as shown in FIG. 2C.

This tree topology formation process is performed asynchronously at all nodes including Node C during the topology formation time, so that the sensor network forms a tree topology for a standard route as shown in FIG. 2D.

Here, the tree topology formation time is set in advance by a network operator or the like and has a value that is increased in proportion to the size of the sensor network.

However, the tree topology forming process is performed only once for each node, and if a particular node fails to participate in the tree topology due to packet collision or interference, or acquires hop count information to the sink node, the node is It becomes a missing node.

Accordingly, the present invention additionally performs the discovery and addition process of the missing node, thereby preventing the possibility of the missing node.

3 is a view for explaining the neighbor node information reporting process (S20) according to an embodiment of the present invention in more detail.

Referring to FIG. 3, a node (eg, node E) located at the lowest level generates a neighbor node information message including its neighbor node information and delivers the neighbor node information message to the parent node (node C).

A node located at an intermediate level (for example, node A) receives a neighbor node information message provided from several child nodes (nodes C and D) over a period of time, and the neighbor node included in the received neighbor node information message. It collects the information and its neighbor node information and delivers it back to the node (sink node) located at a higher level.

At this time, the node located at the intermediate level compares neighbor node information transmitted from several child nodes with its neighbor node information in order to improve message transmission efficiency, merges duplicated information into one information, and transmits the information to the parent node. . In addition, depending on the message capacity, it may be divided into one message or several messages.

The sink node located at the highest level receives the neighbor node information message provided from several child nodes over a predetermined time period, collects the neighbor node information included in the received neighbor node information message and its neighbor node information, and acquires the entire sensor. Obtain neighbor node information for network

In this way, the sink node receives all the neighbor node information collected from each node, and performs tasks such as scheduling or location recognition.

4A to 4C are diagrams for explaining in detail a process of finding and adding a missing node (S30) and a reporting of missing node information (S40) in a tree topology according to an embodiment of the present invention, which is a depth-first search. This is done at each node, going from top level to bottom level in some way.

Hereinafter, for convenience of description, the operation in the node D will be described as an example.

The node D broadcasts a missing node discovery request message including its ID information, hop count to the sink node, and node discovery request information as shown in FIG. 4A to the neighboring nodes.

Nodes A, C, G, and J located adjacent to node D receive the missing node discovery request message of node D, and have previously received the node discovery request message and transmitted the node discovery response message. G just discards the missing node discovery request message.

On the other hand, Node J, which first received the Missing Node Discovery Request message from Node D, confirms that it was missing from the tree topology, generates a Missing Node Discovery Response message including its identity information, and sends it to Node D. Node J then sets its hop count to the number of hops included in the missing node discovery request message plus " 1 " and participates in the tree topology as shown in FIG. 4B.

In response to the node J's missing node discovery response message, node D adds node J's ID information and updates it to its neighbor node information, and then retransmits the updated neighbor node information to the sink node. Do it.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those skilled in the art.

1 is a diagram schematically illustrating a neighbor node discovery and reporting method in a sensor network according to an embodiment of the present invention.

2A to 2D are diagrams for explaining a tree topology forming process according to an embodiment of the present invention in more detail.

3 is a diagram illustrating a neighbor node information reporting process in more detail according to an embodiment of the present invention.

4A to 4C are diagrams for explaining in detail a process of finding and adding a missing node and reporting a missing node information in a tree topology according to an embodiment of the present invention.

Claims (12)

Forming a tree topology for the sensor network; Collecting neighbor node information from each node of the tree topology and delivering the neighbor node information to the sink node through a routing path; Sequentially rescanning the tree topology to find and add missing nodes to the tree topology; And And transmitting the information of the missing node to the sink node in the node that finds the missing node. The method of claim 1, wherein the forming of the tree topology is performed. Broadcasting a node discovery request message at each node, and receiving a node discovery response message; Analyzing the node discovery response message to obtain neighbor node information; And And selecting a node having a minimum hop count from a neighbor node transmitting the node discovery response message as a parent node as a parent node to participate in a tree topology. The process of claim 2, wherein the forming of the tree topology is performed. A method for discovering and reporting neighboring nodes in a sensor network, which is performed at each node while sequentially progressing from a top level node to a bottom level node. The method of claim 2, wherein the node discovery request message is A method for discovering and reporting neighboring nodes in a sensor network, comprising node ID information and node discovery request information. The method of claim 2, wherein the node discovery response message A method for discovering and reporting neighboring nodes in a sensor network, comprising node ID information. The method of claim 1, wherein the transferring to the sink node is performed. Transmitting, by the node located at the lowest level, its neighbor node information to the parent node; A node located at an intermediate level collects neighbor node information transmitted from the child node and its neighbor node information and transmits the neighbor node information to the parent node; And obtaining, by the sink node located at the highest level, neighbor node information transmitted from the child nodes to obtain neighbor node information for the entire sensor network. The method of claim 6, wherein collecting the neighbor node information and delivering the neighbor node information to a parent node comprises: A method for discovering and reporting neighboring nodes in a sensor network, comprising comparing neighboring node information transmitted from a child node with its neighboring node information and merging overlapping information into one piece of information. The method of claim 6, wherein collecting the neighbor node information and delivering the neighbor node information to a parent node comprises: A method for discovering and reporting neighboring nodes in a sensor network, comprising collecting neighboring node information transmitted from a child node and its neighboring node information, and then dividing the neighboring node information into a plurality of messages. The method of claim 1, wherein the finding and adding the missing node to the tree topology is performed. Broadcasting a missing node discovery request message at each node; Generating and transmitting a missing node discovery response message and participating in the tree topology, wherein the missing node which has not received the node discovery request message among the nodes that have received the missing node discovery request message; And And receiving the missing node discovery response message by analyzing the missing node discovery response message to obtain information of the missing node. 10. The method of claim 9, wherein the missing node discovery request message is A method for discovering and reporting neighboring nodes in a sensor network, comprising node ID information, hop counts to sink nodes, and node discovery request information. 11. The method of claim 10, wherein the step of finding the missing node and adding it to the tree topology And setting the number of hops of the missing node by adding the number of hops to the sink node included in the missing node discovery request message by adding "1". How to report. 10. The method of claim 9, wherein the missing node discovery response message is A method for discovering and reporting neighboring nodes in a sensor network, comprising node ID information.

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