Research On A Distributed Range-Free Localization Algorithm For Wireless Sensor Networks

Wireless Sensor Networks is a new ad-hoc network-technology combining technologies sensor, wireless communication and embedded system. It can be widely applied in military surveillance, environment monitoring, healthy caring, smart space and other commercial applications, and is becoming a hot topic in wireless communication researches. Among which the sensor localization is a fundamental and crucial issue for WSNs.The localization algorithms for WSNs can be divided into two categories: the range-based and the range-free. The range-based algorithms have better accuracy, but require additional hardware at the sensor nodes, which are not available on regular application fort of sensor networks, and the range-free algorithms are being pursued as a cost-effective alternative. The range-free algorithm makes no assumption about the availability or validity of range information. There are two problems need to be solved in this paper:一,lower estimation error; lower communication overhead;二,relize localization flexibily;In this paper, an efficient Distributed Range-Free Localization (eDRFL) algorithm is proposed, which just need the anchors to flood their location information, and the blind nodes within one hop range of anchors save the beacons of heard anchors and localize themselves. The eDRFL consumes lower communication overhead, and is robust to the network connectivity. In our simulation, the estimation error of location by the eDRFL is less than 8% of the communication range of the blind node, when ANR=8 and 16 anchors uniformly deployed in the simulative terrain. The estimation error can be lower than 0.3R under shadowing model, and the result is independent of network connnections. The "undetermined nodes" problem is not exit under eDRFL algorithm.