Energy-efficient optimization for physical layer security in large-scale random CRNs

Energy-efficiency, high data rates and secure communications are essential requirements of the future wireless networks. In this paper, we develop a framework to study the energy efficiency for enhancing physical layer security (PLS) in large-scale random cognitive radio networks (CRNs) considering the node spatial distribution, wireless propagation medium and aggregate network interference. Using stochastic geometry, we model the large-scale random secure CRN, and analyze the connection outage probability (COP) and the secrecy outage probability (SOP) of typical secondary link. Based on the results, we introduce the secrecy energy efficiency (SEE) to character the energy efficiency for enhancing the physical layer security of secondary network. Furthermore, we jointly optimizing the medium access probability (MAP) and transmit power of secondary transmitters (STs) to maximize the secrecy energy efficiency. Finally, numerical results are conducted to evaluate the SEE and examine the effect of system parameters.