Optimal power allocation for energy‐efficient full‐duplex cognitive relay networks under primary interference

Abstract

This study investigates optimal power allocation (OPA) for maximising the energy efficiency (EE) of dual-hop underlay full-duplex cognitive relay network, under the influence of interference from primary source. The OPA for the EE optimisation is constrained on the maximum transmit power of the secondary nodes and the interference threshold power which can be tolerated at the primary destination. The authors convert the initial non-convex optimisation problem to a concave fractional programming form and propose an iterative algorithm using parametric transformation to find the OPA vector. Further, they prove that the point of convergence of the proposed iterative algorithm is a Karush–Kuhn–Tucker point of the initial non-convex problem. They numerically demonstrate the EE improvement achieved by the proposed algorithms over equal power allocation strategy.