Reactive sink mobility in wireless sensor networks

The ability of a sink node to move can greatly improve the fault tolerance and load balancing properties of a sensor network. Rather than assuming extensive mobility and trying to minimize the large-scale path loss between the mobile sink and the nodes, we focus on limited-scope, arbitrary mobility triggered in response to a form of network feedback. Due to multipath fading effects, limited mobility dynamically modifies the set of sink neighbors and distributes network traffic over a larger number of nodes. We illustrate the impact of this reactive sink mobility concept on data collection by implementing it on top of a novel gradient-based routing protocol. We use Berkeley motes to present a proof of concept as well as a performance evaluation of our approach, with a particular emphasis on the advantages in terms of robustness and lifetime.