In many applications, wireless sensor networks (WSNs) are deployed in inhospitable environments and therefore the nodes are at increased risk of failure. Large scale damage may partition a network into disjoint segments, which has very negative effect on the application. Mobile nodes have been exploited to act as mobile data collectors (MDCs) among segments to restore the connectivity of WSNs in the previous works. However, almost all of the works assumed that mobile nodes travel via a direct path, which may not be the case in real-world applications. In order to improve the applicability of the recovery strategy, obstacles should be taken into account. In this paper, we present an obstacle aware connectivity restoration strategy (OACRS) to fit these requirements. Our algorithm is designed for the scenarios that the number of available relays is less than the number of relays required to construct stable links and more than the number of segments. At first we construct and optimize the obstacle-avoiding minimum spanning tree of the segments and then determine the relays which keep static and the ones which act as MDCs. Finally we optimize the tour path of MDCs. The effectiveness of the proposed algorithm is validated through simulation experiments.
['Guizhen Ma', 'Yang Yang', 'Xuesong Qiu', 'Zhipeng Gao']
Obstacle Aware Connectivity Restoration for Disjoint Wireless Sensor Networks Using a Mix of Stationary and Mobile Nodes