Method of refining node position information in wireless sensor network

• US 20070159986A1
• Filed: 01/09/2007
• Published: 07/12/2007
• Est. Priority Date: 01/09/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Jong-hun, Park, Woo-jong, Jeong, Min-seop, Kim, Dae-young, Yoo, Seong-eun, Kim, Min-q
• Granted Patent: US 7,835,333 B2
• Time in Patent Office: Days
• US Class Current: 370/254
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Provided is a method for refining node position information in a wireless sensor network having an ultra wideband communication network and a wireless personal area network where the initial positions of respective nodes are set, by utilizing nodes at a 2-hop distance, or more than a 2-hop distance when the number of neighboring nodes at a 1-hop distance is not sufficient to perform triangulation, and to refine the position of nodes based on a distance measured between the respective nodes. Because the initial position is refined and confirmed in a wireless sensor network, a user node operates as a pseudo anchor node for the nodes which have no anchor node nearby. Furthermore, as a node has the refined position, it can act as a pseudo anchor node and be used to compute the position of the other nodes. Additionally, positions of nodes of the wireless sensor network can be estimated with more accuracy.

Claims

1. A method of refining a node position information in a wireless sensor network, comprising:

setting an initial position based on an anchor node;

receiving a position refining message from the anchor node;

refining the initial position by measuring a distance to neighboring nodes based on the anchor node; and

notifying the refined position, by switching into a pseudo anchor node based on a refined position information, and broadcasting the refined position information and a pseudo anchor information to the neighboring nodes.

2. The method of claim 1, wherein in the receiving of the position refining message, the position refining message, which is broadcast from the anchor node, is received.

3. The method of claim 1, wherein in the setting of the initial position, the initial position is refined using three anchor nodes, including anchor nodes within a two-hop distance, or more than the two-hop distance, when the three anchor nodes do not exist among the neighboring nodes within a 1-hop distance.

4. The method of claim 1, wherein in the setting of the initial position, the neighboring nodes set a standby time and count the standby time while waiting for the initial position to be refined.

5. The method of claim 4, wherein the neighboring nodes cancel the standby time and perform refining of a next node that has three or more anchor nodes including the pseudo anchor node within a 1-hop distance as its neighboring nodes, when the neighboring nodes receive the refined position information.

6. The method of claim 1, wherein in the notifying of the refined position, the anchor node learns a coefficient of a distance function using other anchor nodes and the pseudo anchor node, and

a node newly entering the wireless sensor network utilizes the learned coefficient of the distance function which is provided from the anchor node, in setting its position.

7. The method of claim 1, wherein in the notifying of the refined position, the neighboring nodes, on receiving the refined position information and the pseudo anchor information, use one or more anchor nodes at a multi-hop distance, when there are less than three anchor nodes within a 1-hop distance.

8. The method of claim 7, wherein the anchor node that is a less number of multi-hops away from the neighboring nodes has a priority.

9. The method of claim 1, wherein in the receiving of the position refining message, the position refining message is transmitted to the anchor node to start the refining of the initial position, when the set initial position is changed by more than a predetermined distance.