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 (WSNs). This paper provides another solution to the sink mobility problem in WSNs by incorporating node-load parameters into a matrix based on alternative sink positions and using this matrix to determine the next sink site to visit in each round. We first present a packet-load based sink movement algorithm that considers how many packets each node would receive and transmit for each different sink position. We extend this algorithm by also 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 the optimal results. Our extensive simulations show that our packet- and energy-load based algorithms significantly improve network lifetime without introducing much overhead and only remain around 5% behind the optimal solution.