Performance study of localization methods for ad-hoc sensor networks

In ad-hoc wireless sensor networks, one approach for estimating the positions of sensor nodes is to use connectivity information of the network or local distance measurement. We compare two representative methods, multilateration and MDS-MAP, and study some of their key issues that affect the performance. First, we study the various optimization techniques and the effect of anchor selection for multilateration and the effects of the sizes of local maps and the refinement techniques for MDS-MAP. Secondly, we investigate the error property of localization by deriving the Cramer-Rao bound for different topologies and compare the bounds with the results of the two methods on different anchor placements. Previous results suggest that anchors should be placed on the perimeter of the network to get more accurate solutions. Our results show that MDS-MAP tolerates "ill placement" of anchors much better than multilateration. Finally, we compare the performance of the two methods through extensive simulation and identify the situations when one method is better than the other.