Enhancing wireless communication privacy with artificial fading

This paper addresses the problem of anti-eavesdropping in wireless network physical layer. The main contribution of this paper is twofold. First, we propose a novel concept of artificial fading that is produced by double-beam switching of smart antenna array to intentionally corrupt unwanted wireless communication links. Second, we develop a physical layer anti-eavesdropping scheme to minimize the unnecessary coverage area, and hence, lower the chance of being eavesdropped. Our anti-eavesdropping scheme employs smart antenna with two synthesized radiation patterns, which are optimized to provide good signal quality to the intended receiver, while their overlap apart from the intended direction is minimized. During the transmission, the transmitter periodically alternates between the two optimized patterns at a high frequency, which produces severe fading to the received signal in undesired directions. Since such signals are corrupted and cannot be decoded, eavesdropping is prevented. Simulation experiments show that our anti-eavesdropping scheme outperforms single pattern beamforming in reducing the unnecessary coverage area exposed to eavesdroppers.