Traffic- and energy-load-based sink mobility algorithms for wireless sensor networks

Moving the sink node is an effective solution for improving the lifetime of wireless sensor networks (WSN). Different methods in the literature schedule sink movements and determine sink stay points. This paper provides another insight to the sink mobility problem in WSNs by incorporating node-load parameters into a matrix and using this matrix to determine which sink site to visit in each round. We first present a packet(traffic) load–based sink movement algorithm that relies on the packet distribution of nodes in each sink site for a given topology construction algorithm. We extend this algorithm by considering the distances the packets are transmitted, and in this manner obtain an energy-load–based algorithm. We also provide an integer programming (IP) model to compute optimal results. Our extensive simulations show that our energyand packet-based algorithms significantly improve network lifetime compared to keeping the sink static or moving it randomly. Our energy-based algorithm can increase network lifetime by a factor of 2 compared to random movement and by a factor of 5 compared to keeping the sink static. It remains only around 5% behind the optimal solution.