Secrecy outage probability of UAV-aided selective relaying networks

Abstract

In this work, we analyze the secrecy outage probability of unmanned aerial vehicle (UAV)-aided selective relaying networks with M UAV-transmitters (UTs), N UAV-relays(URs), and K collaborative UAV-eavesdroppers (UEs). In the main channel, the best UT-UR pair is selected to transmit the source message to the destination, while unreliable ground-to-air (G2A) wireless backhaul across multiple UTs is considered. In the eavesdropper channel, the UEs intelligently exchange the information received form the UTs and URs, while eavesdropping probability among UEs is considered. Due to non-ideal line of sight transmission, network congestion, and synchronization, we introduce backhaul reliability to reflect the practical constraint on G2A wireless backhaul. To reflect UEs' synchronization to the main channel and their consumed communication resources for inner-information exchange, we introduce eavesdropping probability to describe the cost of UE collaboration. The exact secrecy outage probability is presented in a closed form. It is shown that the asymptotic secrecy outage probability is exclusively determined by M, N, and backhaul reliability. Simulation results verify the accuracy of the analytical expressions.