Efficient localization in mobile wireless sensor networks

The proposed DRL is a distributed range-free localization approach. In order to save communication cost in localization, DRL reduces information flooding among nodes by dynamically changing each seed´s flooding-hop to limit seed flooding in a local area; however, it still maintains the whole coverage. In addition, DRL allows all the nodes mobile and moving freely, while there is only a limited fraction of nodes having self-positioning capability (called seeds). Moreover, DRL can adapt to low or high node density, because of its dynamic seed flooding and robust triangulation. Dynamic seed flooding is to change flooding coverage according to each seed´s surrounding node density. Robust triangulation allows the cases of insufficiency of reference nodes. We have evaluated DRL and MCL. Simulation results have shown that the location accuracy of DRL is 26% higher than that of MCL. With mobile positioning, DRL is suitable for applications, such as navigation systems using e-map and community health-care systems, in outdoor environments