Active Eavesdropping in Short Packet Communication - Average Secrecy Throughput Analysis.

In this paper, we investigate secure short packet transmission from a legitimate transmitter to a receiver in the presence of an active eavesdropper. The aim is to gain more insights into how an active eavesdropper affects the secrecy throughput of short packet communications. The eavesdropper is assumed to have full-duplex (FD) capability, which enables performing eavesdropping and jamming simultaneously. All the communication links in the wiretap channel are assumed to be Rayleigh fading. An approximation of the average achievable secrecy throughput is proposed to measure the security of the system. The proposed approximation is examined and analysed in two different topology scenarios, which are triangular and line topologies. Then, Monte-Carlo simulations are performed to get an understanding of how good the approximation is. The results show that the closed-form expressions have a good match with Monte-Carlo simulations. We also investigate the impact of the eavesdropper's distance to the legitimate nodes as well as the different jamming power levels. Furthermore, self-interference influence on the eavesdropper is discussed.