A node localization scheme for zigbee-based sensor networks

The localization problem consists in estimating the position of the nodes within the network. This is a crucial issue for location-dependant applications. This paper presents an implementation of a localization scheme based only on the received signal strength (SS) in a Zigbee-based sensor network. This is done by taking advantage of the inherent radio communication capability present in each node. The algorithm is intended for an outdoor environment. It is based in a model, which infers distance between neighboring nodes using the SS. A coordinate system is then derived employing a multidimensional scaling (MDS) technique. The signal power level variability due to ground reflection is approached using Lloyd effect (from optics) and incorporated in the model.