Energy and terrain aware connectivity restoration in disjoint Mobile Sensor Networks

In Mobile Sensor Networks (MSNs), connectivity of the sensor nodes with the sink node can be disrupted due to failure of some nodes which may result network partitioning. To address this problem, mobility of the nodes has been exploited in the previous works so that an autonomous recovery can be achieved. All of these works have assumed reachability of the nodes to the selected destinations via a direct path movement. However, in real-world applications, such assumption makes the schemes impractical in case of encountering obstacles or intolerable terrains based on the kinematics of the mobile nodes. Besides, even if direct path movement is successful, optimal energy efficiency cannot be attained by neglecting the elevation or friction of the terrain when determining the movement path of the nodes. Thus, in the recovery efforts, terrain type, elevation as well as the obstacles should be taken into account in order to guarantee the connectivity restoration while minimizing the recovery cost in terms of energy. In this paper, we re-design an existing connectivity restoration approach in disjoint MSNs to fit these requirements and evaluate the performance issues when realistic terrains are assumed. Rather than following a direct path, movement trajectory is determined based on a path planning algorithm which considers the risk and elevation of terrain sections to be visited while avoiding obstacles and highly elevated terrain sections. Experiments have revealed that the direct path movement fails for many topologies while the proposed approach guarantees a solution. Besides, the proposed approach significantly outperforms direct path movement without obstacles in terms of total energy consumption.