Scalable location estimation using smart antennas in wireless sensor networks

For Wireless Sensor Networks (WSNs), although many localization techniques have been proposed, development of effective localization techniques for sensor nodes, which do not require any hardware or computational burdens on them, continues to be a challenging task. Motivated by this need, this paper proposes a new location discovery scheme in WSNs so called Sectoral Sweeper based Location Estimation (SSLE). Sectoral Sweeper (SS) relies on integration of smart antenna processing capability only at a central node. By expanding the SS scheme, the key idea in the SSLE is to perform two dimensional (azimuth and range) sweeping process over a given sensor field with beamforming capable central node followed by range estimation and direction estimation algorithms. It does not require any hardware or computational load at tiny sensor nodes. Performance evaluation of the SSLE is given in terms of localization error, response message statistics, and complexity analysis for grid and randomly deployed sensor node scenarios under various sweeping conditions. The SSLE performance is also compared with the Centroid method. The advantage of the SSLE is that it is applicable to environments with hard-to-access sensor deployment scenarios and that desired localization accuracy can be obtained by properly adjusting sweeping parameters.