Minimization of Energy-Efficient Outage Probability in AF-Relayed PLC

Energy-aware resource allocation to achieve desired throughput over cooperative power line communications (PLCs) has gained growing interest from past few years. In this article, we design an energy-efficient amplify-and-forward relay-assisted PLC, where outage probability based on energy-efficiency is minimized by jointly optimizing the relay location and power allocation (PA) in two scenarios: 1) absence and 2) presence of the end-to-end direct link. To reduce complexity, using a novel and nontrivial approach, we obtain a closed-form expression of the outage probabilities for both the scenarios. Further, an equivalent problem is formulated to make the optimization problem more tractable to obtain its solution. In the absence of direct link, a closed-form solution of the problem is obtained by the optimization schemes where underlying variables are optimized individually and jointly. While, in the presence of the direct link, a closed-form solution is obtained using a nontrivial tight approximation algorithm. Via numerical results, the outage expressions are validated, and various insights on optimization of PA and relay location are obtained. Finally, with respect to energy-efficiency, it is shown that the joint optimization gives an outage improvement of around 55% and 37% in the absence and presence of the direct link, respectively.