An Energy Efficient and Restricted Tour Construction for Mobile Sink in Wireless Sensor Networks

Mobile sinks have been used recently, mainly to minimize energy consumption and to resolve some other issues including data collection from disconnected networks, energy depletion from sensor nodes which are close to the sink, etc. In this paper, we address the problem of finding an optimal path for the mobile sink to traverse through the sensing field, to collect a single packet from each sensor and return back to its initial point (starting point) such that the total energy use is minimized and subject to the length constraint L. We refer to this as the minimum energy cost mobile sink restricted tour problem (MMRTP), and show that this problem is NP-hard. Second, we propose two algorithms. The first algorithm is a heuristic one based on the maximum ratio criteria, while the second algorithm is based on the dynamic programming technique. We consider two scenarios for each algorithm. In the first scenario, there is no restriction on the transmission range of the nodes, whereas in the second scenario, the maximum transmission range is Rmax. Finally, we evaluate the performance of our proposed algorithms based on the MATLAB simulations for two different network sizes and show their effectiveness in terms of energy consumption. Moreover, the simulation results show that our second proposed algorithm has significant impact on energy consumption in comparison with the algorithm of [20] for the same parameters (i.e. Lengths and transmission ranges).