Dual-threshold based secure on-off transmission scheme for dense HCNs with imperfect CSI

In this paper, we propose a dual-threshold based secure On-Off transmission scheme, where signals are transmitted only if the channel condition can guarantee secure and reliable communication. First, we present a dynamic access strategy to increase access efficiency, which provides an access region for the intended user. Then, we propose an emission control policy to transmit signals according to the current channel condition, which declines the influence of channel estimation errors and guarantees qualities of communication links. Furthermore, we give a comprehensive performance analysis for the proposed scheme in terms of connection outage probability (COP) and secrecy outage probability (SOP), and present a dual-threshold optimization model to further support the performance. Numerical results verify that the secure On-Off transmission scheme can increase the system secure energy efficiency and guarantee reliable and secure communication.