Boundary recognition by topological methods in wireless sensor networks

All applications of the wireless sensor network is closely related to the underlying environment in which the sensors are deployed. The topology of the sensor network is great importance for sensor network applications and the implementation of networking function[1]. The recognition of the boundary or the inner hole boundary of the network is the basic of a broad spectrum of algorithms. In the paper we study use the topology construction for find the boundary of network. Boundary node include inner hole boundary nodes and outside boundary nodes. About the interior boundary node and outside boundary, in the main text we will give a definition. Our algorithm is a scalable and range-free solution for boundary recognition methods that is not require a high node density. In this algorithm, we do not assume any information about node´s location and do not enforce that the communication graph follows the unit disk graph model. Suppose that a large number of sensor nodes are scattered in a geometric region and every nodes communicating with the node nearest to itself. Our goal is to find the boundary of the network only use the nodes topology connection. We provides a simple, distributed algorithm that can quickly detects nodes on the boundary.