Energy-efficient optimization in cooperative networks with wireless information and power transfer

This paper considers a decode-and-forward (DF) relaying wireless cooperative network, in which the energy harvesting relay is powered by radio-frequency (RF) signal from the source and then the harvested energy is used to support the relay transmissions. Based on the two different energy harvesting strategies, i.e. time switching-based relaying (TSR) protocols and power splitting-based relaying (PSR) protocols, we study the optimization of energy efficiency in wireless cooperative networks. Although the formulated optimization problem is not convex, it can be re-constructed in a convex form by using the non-linear fractional programming, to which closed form solutions can be found by using the Lagrange multiplier method. The simulation results are presented to verify the effectiveness of this solution proposed in this paper.