Mobility-assisted localization techniques in wireless sensor networks: Issues, challenges and approaches

Many network operations and applications of wireless sensor networks (WSNs) need sensor nodes for obtaining their locations. Sensor nodes equipped with geographical positioning system (GPS) devices are aware of their locations at a precision level of few meters. However, installing GPS devices on a large number of sensor nodes is not only costly but affects the form factor of these sensor nodes. Moreover, GPS-based localization is not applicable in indoor environments such as buildings. There exists an extensive amount of research literature that aims at obtaining absolute locations as well as relative spatial locations of sensor nodes in a wireless sensor network without requiring specialized hardware at large scale. The typical approach that significantly reduces the cost is replacing the large set of statically deployed GPS-enhanced sensor nodes with limited number of mobile anchors. These mobile anchors are aware of their own locations and move in order to cover the entire network, and then try to infer locations of sensor nodes using various techniques e.g. geometric, statistical etc. Thus, keeping this in mind the chapter presents key issues and inherent challenges faced by the mobility-assisted localization techniques in WSNs. Also, we take a close look at the algorithmic approaches of various important fine-grained mobility-assisted localization techniques applicable for low power, resource constrained and highly distributed sensor nodes.