Anchor-Free Localization Algorithm for underwater sensor networks

Due to limited bandwidth, severely impaired channel and non-negligible node mobility, localization for Underwater Wireless Sensor Networks (UWSN) is very challenging. Most of existing localization schemes assume that the network has a plurality of auxiliary anchor nodes to assist positioning. As Global Positioning System (GPS) and other existing direct positioning technologies do not work efficiently in underwater environment, usually take Autonomous Underwater Vehicle (AUV) or node with special equipment as anchor node. High cost and poor flexibility make them not well suitable for UWSN. In order to overcome this disadvantage, we propose an Anchor-Free Localization Algorithm, called AFLA. It is designed for active-restricted underwater sensor networks. AFLA does not need anchor node´s information, and makes use of the relationship of adjacent nodes to calculate node positions. It could be used in both static and dynamic networks. The obtained simulation results indicate that AFLA is an effective localization scheme for UWSN.