Time switching based, outage‐constrained, energy harvesting and energy‐efficient cooperative radio communication policy

In this work, the authors consider a two‐hop cooperative radio communication system that consists of energy harvesting relays. The EH relays harvest energy from its received radio frequency signal. The EH relay nodes adopt the time‐switching protocol for simultaneous EH and information processing. For the system model, the authors propose an energy‐efficient, outage‐constrained relaying policy. In it, the EH relay that harvests maximum energy forwards the information to the destination. However, the selected EH relay transmissions are outage‐constrained. For the proposed outage‐constrained collaborative EH system model, the authors present insightful analysis. Specifically, the authors derive a single integral expression for the expectation of maximum energy harvested over frequency‐flat Rayleigh fading and shadowing channel. The authors also present an insightful link outage probability analysis and asymptotic analysis in a useful scaling regime. Besides outage analysis, the authors investigate the proposed policy's performance in terms of average spectral efficiency and average energy efficiency. To validate the analytical results, the authors conduct numerical simulations. Using the numerical plots, the authors quantify the proposed policy's link outage and energy efficiency performance gains compared with benchmark policies. The proposed outage‐constrained, green cooperative communication policy and its analysis are useful for green collaborative EH systems.