What is Data-Gathering Round

In a static wireless sensor networks (WSN), the fundamental issue is the formation of energy hole in the sink's immediate locality. The solution to the energy-hole problem can be resolved by incorporating mobile entities like mobile robot (MR) into the network. This chapter proposes three strategies that exploits the mobility of the MR to overcome the energy-hole problem resulting in optimized energy usage across the network and thus maximized network lifetime. Firstly, the energy hole problem using MR is formulated as an optimization model to maximize the sojourn time of the MR at each node and a MR-ranking heuristic that ranks the critical node to be serviced is proposed. Secondly, MR-optimal scheme that finds the optimal path for the MR is formulated and designed. Thirdly, Multi-MR cooperation approach is proposed where multiple MR's collaborate to service the critical nodes. Adequate experiments have been performed to analyze the performance of the proposed schemes. The proposed methods ensure uniform energy distribution and prolonged network lifetime.