Joint Sink Mobility and Data Diffusion for Lifetime Optimization in Wireless Sensor Networks

timization under storage constraint for wireless sensor networks with a mobile sink node. The problem is particularly challenging since we need to consider both mobility scheme and storage con- straint. Previous works suggest to use a simple single-hop routing model in which source nodes can only communication with the sink node directly in those mobile networks, However, we notice that this statement is unsuitable for sensor networks with storage constraint because we prove it is a NP-complete problem under single-hop routing model by reducing the Traveling Salesman Problem (TSP) to it in polynomial time. Hence, we try a different way. First we analyze this problem and give a lifetime upperbound, so whether this upperbound is tight is what we concern mostly. Thus, we first construct a 2-approximation O(n2) algorithm to solve the TSP problem, then a novel data diffusion mechanism is built to achieve this upperbound. We prove that under some reasonable assumptions, our algorithm can output this optimal lifetime.