A Range-free Localization Scheme Using Mobile Reference Nodes for Wireless Sensors

Abstract

Localization is one of the substantial issues in wireless sensor networks. Several approaches, including range-based and range-free, have been proposed to calculate positions for randomly deployed sensor nodes. With specific hardware, the range-based schemes typically achieve high accuracy based on either node-to-node distances or angles. On the other hand, the rangefree mechanisms support coarse positioning accuracy with the less expense. This paper describes a range-free localization scheme using mobile reference nodes. Each reference node equipped with the GPS moves in the sensing field and broadcasts its current position periodically. The sensor nodes obtaining the information are thus able to compute their locations. With the scheme, no extra hardware or communication is needed for the sensor nodes. The localization mechanism has been implemented in the network simulator ns-2. The experimental results show that the location error for our scheme was less than 1 meter on average.