Design and optimization of secure transmission scheme for random cognitive wireless networks

This paper designs a new chance transmission scheme for the cognitive wireless network with randomly distributed wiretap nodes. Under the condition that the channel estimation error exists at receiver and the channel information of the wiretap channel is unknown, the closed expression of the system's secrecy outage probability, connection outage probability and secrecy throughput is deduced. Based on these, we obtain the trade-off between the secrecy throughput and energy efficiency. Finally, under the requirement of security and reliability, the optimal pilot length and transmit power under the transmission scheme are obtained by maximizing the compromise function. The simulation results verify the correctness of the theoretical analysis and show that the gain of the net secrecy throughput is improved after adding the pilot. Considering the energy efficiency, the transmit power has an optimal value to maximize compromise function, and we obtain the expression of most superior power.