Optimum SWIPT relaying in bidirectional non‐regenerative relay networks

Abstract

The authors study the optimal design of simultaneous wireless information and power transfer relaying in bidirectional non-regenerative relay networks. They consider both power splitting relaying and time switching relaying. Since there are two opposite traffic flows between two sources, they characterise the transmission rate performance by the minimum rate of two opposite traffic flows. Specifically, they first obtain closed-form expressions for the optimum power splitting and time switching coefficients to maximise the minimum transmission rate of bidirectional non-regenerative relaying. They also derive the resulting maximum transmission rate expressions. Furthermore, they consider a minimum input radio frequency (RF) power level to turn on diodes, and derive the turn-on probability of the RF energy harvesting circuit when two channels experience independent Rayleigh fading. Numerical results confirm that the authors' analyses exactly match with simulation results and that the two relaying strategies with optimum coefficients give almost the same transmission rate performance.