A Sequential Cluster-Based Approach to Node Localizability of Sensor Networks

This paper addresses the node localizability problem in 2-D, aiming at determining which nodes are localizable in a sensor network with internode distance measurements. Toward this objective, a sequential cluster-based approach is proposed. The idea is to expand the set of localizable nodes starting from the set of anchor nodes cluster by cluster rather than node by node. Taking computation efficiency in practice into account, we consider the size of a cluster up to four nodes each time. Then, we develop a necessary and sufficient condition to determine whether a cluster up to four nodes is jointly localizable given the distance measurements among them and the distance measurements between them and their neighbors with known coordinates. In terms of this necessary and sufficient condition, both centralized and distributed algorithms are developed for detecting localizable nodes in a given sensor network. It is demonstrated that our approach outperforms well-known techniques, such as trilateration, bilatration, and wheel extension in finding as many localizable nodes as possible.