Silent Antenna Hopping Transmission Technique for Secure Millimeter-Wave Wireless Communication

In this paper, we propose a new wireless communication transmission technique called Silent Antenna Hopping (SAH) transmission technique, to enhance physical layer security. SAH consists of a conventional phased-array transmitter followed by antennas with an on-off switching circuit. The proposed solution maintains the objective of scrambling the constellation points in both amplitude and phase in undesired directions, while preserving a clear constellation in the target direction. SAH is different from the previously-used work in the following ways: (1) SAH is not restricted to the use of phase modulation, and can accept any modulation type including QAM, (2) it does not need to modulate the signal in the RF domain, where the conventional phased-array transmitter circuits remain unchanged, (3) in the far-field, SAH scrambles the signal constellation by randomly switching-off only one of the transmitting antennas, (4) SAH can easily integrated with the current infrastructure of phased-array transmitters, and (5) SAH breaks up the correlation between the data rates and the switching speed. We analysed the SAH performance and derived an exact expression of the bit error probability, and we derived the secrecy capacity in a closed form. The results show that SAH is a simple and very efficient solution to improve the physical layer security of mm-wave communication.