Coordinated and controlled mobility of multiple sinks for maximizing the lifetime of wireless sensor networks

We define scalable models and distributed heuristics for the concurrent and coordinated movement of multiple sinks in a wireless sensor network, a case that presents significant challenges compared to the widely investigated case of a single mobile sink. Our objective is that of maximizing the network lifetime defined as the time from the start of network operations till the failure of the first node. We contribute to this problem providing three new results. We first define a linear program (LP) whose solution provides a provable upper bound on the maximum lifetime possible for any given number of sinks. We then develop a centralized heuristic that runs in polynomial time given the solution to the LP. We also define a deployable distributed heuristic for coordinating the motion of multiple sinks through the network. We demonstrate the performance of the proposed heuristics via ns2-based simulations. The observed results show that our distributed heuristic achieves network lifetimes that are remarkably close to the optimum ones, resulting also in significant improvements over the cases of deploying the sinks statically, of random sink mobility and of heuristics previously proposed for restricted sink movements.