KR101127967B1 - Two-way Routing System in Sensor Network - Google Patents

Abstract

The present invention relates to a bidirectional routing system in a sensor network, comprising: a plurality of sensor nodes having an integrated map which is a value obtained by ORing a node ID assigned to the node ID and node IDs of child nodes; And storing a child map including an integrated map of child nodes among the plurality of sensor nodes, and in order to transfer data to a specific sensor node, AND-operates the node ID of the specific sensor node and the child map to correspond to the child map. And a sink node for passing the data to the specific sensor node via a node.

Sensor Network, Integration Map, Child Map, Bidirectional, Connectivity Reporting

Description

Two-way Routing System in Sensor Network

The present invention relates to a routing system in a sensor network, and more particularly, to manage a routing table for transmitting sensing data generated in a wireless sensor network to a sink node, and to send a command or control data from a sink node to a specific sensor node. A bidirectional routing system in the sensor network for adding and managing routing table entries needed to send data.

In the sensor network of the existing tree routing structure, since all nodes have the address information of the parent node, if a certain data is to be delivered to the sink node, only the address of the parent node needs to send the data to the sink node through the relay. I can deliver it.

However, when data is transferred from a sink node to a specific sensor node, the sink node does not have a routing table entry for the specific sensor node. Therefore, the sink node delivers the data to the child nodes through broadcasting, and the child nodes relay it again. By transmitting data to all nodes in a manner, waste of network resources is severe and there is a problem of degrading the efficiency of the system.

In order to solve the above problem, a method of maintaining a routing table for all other nodes in all nodes including the sink node can be considered.

However, in this method, as the number of nodes increases, the size of the routing table continues to grow, which causes a waste of memory.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and extends a routing table entry that manages only a path from an existing sensor node to a sink node without using broadcasting, thereby extending the path from the sink node to the sensor node. An object of the present invention is to provide a bidirectional routing system in a sensor network that efficiently maintains and manages a routing table.

The present invention for achieving the above object, a plurality of sensor nodes having an integrated map which is a value of OR operation of the node ID assigned to it and the node ID of the child nodes; And storing a child map including an integrated map of child nodes among the plurality of sensor nodes, and in order to transfer data to a specific sensor node, AND-operates the node ID of the specific sensor node and the child map to correspond to the child map. It provides a bidirectional routing system in a sensor network comprising a sink node for passing the data to the specific sensor node via a node.

The present invention includes a plurality of sensor nodes having a unified map which converts the node ID assigned to the node ID using a hash function and ORs the converted node ID and the node IDs of the child nodes; And storing a child map including an integrated map of child nodes among the plurality of sensor nodes, and in order to transfer data to a specific sensor node, AND-operates the node ID of the specific sensor node and the child map to correspond to the child map. It provides a bidirectional routing system in a sensor network including a sink node for passing the data to the specific sensor node via a node.

As described above, the present invention provides a bidirectional routing system in a sensor network capable of efficiently managing a route from a sink node to a sensor node by extending an existing routing table entry without using broadcasting. In addition, it is possible to efficiently use network resources, and to prevent the memory shortage of the system, thereby providing an efficient two-way sensor network communication environment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In the present invention, an upper node is referred to as a "parent node" and a lower node is referred to as a "child node" for a specific sensor node.

1 is a diagram illustrating a bidirectional routing system in a sensor network according to first and second embodiments of the present invention.

Referring to FIG. 1, the bidirectional routing system according to the present invention includes a plurality of sensor nodes 110 and sink nodes 120.

Each sensor node 110 is assigned a node ID having a size of n bits when the number of all sensor nodes including the sink node 120 is n. Here, the node ID has a value of only one bit of n bits has a value of "1", and the other bit has a value of "0".

Each sensor node 110 has an integrated map 112 which is a value obtained by ORing its node ID and node IDs of descendant nodes (all child nodes including child nodes). Here, the integrated map 112 is changed as the configuration of the child node is changed, a description thereof will be described later in FIG.

All sensor nodes including the sink node 120 store the integrated map 112 of their child nodes as well as the integrated map 112, which is called a child map 122. That is, all sensor nodes store the child map 122 together in the child information table directly connected to the sensor node as well as the integrated map 112, which serves as a routing table.

When the sink node 120 wants to send data having a certain destination address, the sink node 120 may visit the corresponding destination using the child map 122. That is, when the sink node 120 sends data to a specific sensor node on the sensor network, the node ID of the corresponding sensor node and the child map 122 of its direct child are ANDed, so that the node ID of the corresponding sensor node may be changed. You can find out if it matches a child map and pass the data to the child node using the node ID of the matching child map. The child node may relay data to a specific sensor node by repeating the above process.

FIG. 2 is a diagram illustrating a process of adding a new sensor node in a sensor network according to the first and second embodiments of the present invention.

In normal tree routing, the parent node changes dynamically, so you must inform all parent nodes, including the parent node. To this end, when a parent node is changed in a plurality of sensor nodes, the sensor node immediately sends an association report message to a series of nodes from the parent node to the sink node and updates the integration map and the child map. FIG. 2 shows that the sensor node sends a connection report message at the moment the parent node changes, and changes the integrated map and the child map accordingly.

As shown in FIG. 2, the connection report message sent from node C changes the unified map 210 of node B, and sink node 200 replaces two table entry values 222 and 224 in child map 220. By changing them all, we can route packets destined for nodes C, E, and F.

Here, only the corresponding sensor node whose parent node is changed sends a connection report message, so that the integration map 230 does not change in node A, which was the parent node, and the child map 220 of the sink node 200 changes routing. Information is always kept up to date.

Node A periodically checks the connection state of the child nodes and automatically updates the unified map 230 and the child map (not shown) to the latest values. This applies not only to node A, but also to all sensor nodes including sink node 200.

In the second embodiment of the present invention, when the sensor node has an arbitrary node ID of 2 bytes, the sensor node is converted to the proposed node ID using this, and routing is performed using the converted node ID. That is, when a node ID is expressed in binary, if only one bit does not have a value of "1", the node ID is converted using a conversion function so that only one bit has a value of "1". Here, a hash function like Equation 1 is used as a conversion function, and if the number of the result of this hash function is n nodes, the function that outputs the least collision value within the range smaller than n is selected. This is preferred.

Routing ID = 2 ^ (Hash (Node ID))

Hereinafter, a transformation method will be described using a simple modular function as an example.

node ID = 9, 18, 43, 28, 13, 22, 39, 64

When the actual node ID of the corresponding node is equal to Equation 2, the actual node ID of Equation 2 is first converted into the remaining values of the modular function as shown in Table 1.

Again, these values take an exponential power of 2, as shown in Table 2.

On the other hand, if the actual node ID is 9 and 65, a collision occurs in which the result of the modular function matches.

3 illustrates a collision between node IDs in a bidirectional routing system according to a second embodiment of the present invention.

Referring to FIG. 3, although the actual node IDs are different, the converted node IDs 310 and 320 match so that the converted node IDs 310 and 320 collide with each other in the sensor network tree. As such, there are two ways to resolve a conflict between two or more node IDs.

First, a common ancestor node (node above parent node) 300 is found for two or more nodes (node E, node G) where a collision occurs, and the ancestor node 300 creates a routing table based on the actual node ID. It is a way to maintain. If a common ancestor node 300 maintains a routing table entry based on the actual node ID for the conflicting nodes (node E, node G), the two nodes (node E, node G) share the same node ID. Even if you do so, you can go to the node based on the actual node ID. 4 is a diagram illustrating a state in which a routing table entry is added in a situation where a collision occurs.

Second, when there is not enough memory to maintain additional routing tables, routing is performed based on all child maps including the node ID which has collided. In this case, when multiple child maps match the node ID, data is sent to all the child nodes. In this case, there is a problem that data is delivered to all the nodes that have collided. However, even in this worst case, the total number of forwarded packets is much smaller than in the case of broadcasting data to all nodes as before. Since redundant transmission of packets occurs in proportion to, it is possible to save network resources.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 is a diagram illustrating a bidirectional routing system in a sensor network according to first and second embodiments of the present invention;

2 is a view for explaining a process of adding a new sensor node in the sensor network according to the first and second embodiments of the present invention;

3 is a diagram illustrating a collision between node IDs in a bidirectional routing system according to a second embodiment of the present invention;

FIG. 4 is a diagram illustrating adding a routing table entry when a collision occurs between node IDs in the bidirectional routing system according to the second embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

110: sensor node 112: integrated map

120: sink node 122: child map

Claims (10)

A plurality of sensor nodes having an integrated map which is a value obtained by ORing a node ID assigned to itself represented by a binary number and a node ID of child nodes; And When storing a child map including an integrated map of child nodes among the plurality of sensor nodes, and wants to transfer data to a specific sensor node, AND operation of the node ID and the child map of the specific sensor node expressed in binary A sink node for transmitting the data to the specific sensor node through a corresponding child node; Bidirectional routing system in the sensor network comprising a. The method of claim 1, The node ID has a size of n bits when the number of sensor nodes is n, and only one bit of n bits has a value of "1", and the remaining bits have a value of "0". Bidirectional routing system in the network. The method of claim 1, The child node receiving data from the sink node ANDs the node ID of the specific sensor node and its child map and transfers the data to the specific sensor node. The method of claim 1, The plurality of sensor nodes change the integration map when a new sensor node is added, and transmit a connection report message including the changed integration map to the sink node. 5. The method of claim 4, And the sink node changes the child map according to the connection report message. A plurality of sensor nodes having an integrated map which is a value obtained by converting a node ID assigned to the node to a remaining value of the modular function by using a hash function and ORing the converted node ID expressed in binary and the node ID of the child nodes; And When storing a child map including an integrated map of child nodes among the plurality of sensor nodes, and wants to transfer data to a specific sensor node, AND operation of the node ID and the child map of the specific sensor node expressed in binary A sink node for transmitting the data to the specific sensor node through a corresponding child node; Bidirectional routing system in the sensor network comprising a. The method of claim 6, And said transformed node ID has a value of only one bit "1". The method of claim 6, The child node receiving data from the sink node ANDs the node ID of the specific sensor node and its child map and transfers the data to the specific sensor node. The method of claim 6, The sink node maintains an actual node ID based routing table entry for the at least two sensor nodes when the IDs of at least two sensor nodes collide with each other by the hash function calculation. Bidirectional routing system in. The method of claim 6, And the sink node broadcasts data to all of the at least two sensor nodes when the IDs of at least two sensor nodes collide with each other by the hash function operation.

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