Secure transmission solutions in energy harvesting enabled cooperative cognitive radio networks

Abstract

In this paper, we investigate secure communications in energy harvesting enabled cooperative cognitive radio networks (CCRNs). In such CCRNs, a pair of primary users (PUs) can only communicate with each other through a relay. To protect data transmission between PUs, we propose a cooperative jamming strategy with energy harvesting technology. In the first phase, a PU as the source (PU-S) broadcasts signals, while another PU as the destination (PU-D) sends artificial noise (AN) and all secondary uses (SUs) harvest energy from the received mixed signals. In the second phase, one SU selected as a relay (SU-R) uses its harvested energy to forward PU's signals, while another SU selected as a jammer (SU-J) employs its harvested energy to send AN. According to this, we formulate a non-convex problem aiming to improve the secrecy rate of PUs and divide this problem into three optimization subproblems. Finally we provide a feasible joint solution by a two-tiered iterative algorithm. Numerical results demonstrate the secrecy performance of our proposed jamming strategy.