Cooperative Wireless Power Transfer for Lifetime Maximization in Wireless Multihop Networks

To extend the lifetime of wireless multihop networks suffering from energy scarcity of constituent nodes, we apply a wireless power transfer (WPT) technology to multihop transmission and allow the nodes with substantial energy to perform WPT to energy-deprived nodes in a cooperative way. We construct a system model for this cooperative WPT (CoWPT)-based multihop transmission and formulate an optimization problem to determine the optimal WPT time of each node for maximizing the lifetime of the multihop network. We first verify that the lifetimes of multihop nodes have the solidarity property, and that the network lifetime is maximized by equalizing their respective lifetimes. Then we convert the considered optimization problem into a tractable linear programming (LP) problem and solve it. Intensive simulations show that the optimal CoWPT solution significantly increases the network lifetime compared with the typical WPT method in both wireless sensor network (WSN) and mobile ad hoc network (MANET) environments. Moreover, it is revealed that the network lifetime is further improved in MANET relative to in WSN because more ambient RF signals are available for energy harvesting in the MANET topology.