Mobility-Based Strategies for Energy Restoration in Wireless Sensor Networks

Energy management has become one of the main hurdles in the quest for autonomous and reliable Wireless Sensor Networks (WSN). This paper examines the emerging problem of increasing network availability by recharging, replacing or redeploying depleted sensors with the help of mobile entities. When mobility becomes a sensor´s attribute and service stations are static, we propose passive vs. pro-active approaches to energy redistribution and restoration. In particular, for pro-active approaches, we study the mobility strategies and underlying topologies that guarantee a successful sensor recharge. The experimental results so far show that taking our novel pro-active approach to energy redistribution and network fatigue outperforms passive strategies. The proposed closest-first swapping-based mobility strategy provides the best overall performance among all the pro-active approaches studied and the proposed Compass Directed Unit Graph provides an efficient and flexible underlying topology to achieve energy equilibrium.