Cluster-Based Routing for the Mobile Sink in Wireless Sensor Networks With Obstacles

In wireless sensor networks (WSNs), the benefits of exploiting the sink mobility to prolong network lifetime have been well recognized. In physical environments, all kinds of obstacles could exit in the sensing field. Therefore, a research challenge is how to efficiently dispatch the mobile sink to find an obstacle-avoiding shortest route. This paper presents an energy-efficient routing mechanism based on the cluster-based method for the mobile sink in WSNs with obstacles. According to the cluster-based method, the nodes selected as cluster heads collect data from their cluster members and transfer the data collected to the mobile sink. In this paper, the mobile sink starts the data-gathering route periodically from the starting site, then directly collects data from these cluster heads in a single-hop range, and finally returns to the starting site. However, due to the complexity of the scheduling problem in WSNs with obstacles, the conventional algorithms are difficult to resolve. To remedy this issue, we propose an efficient scheduling mechanism based on spanning graphs in this paper. Based on the spanning graph, we present a heuristic tour-planning algorithm for the mobile sink to find the obstacle-avoiding shortest route. Simulation results verify the effectiveness of our method.