Broadcasting Multi-beams Antenna Subset Modulation for Secure Millimeter-Wave Wireless Communications

Due to the increasing demand for wireless communications, spectral efficiency of transmission schemes has gained a great concern recently. Also, achieving secure wireless communications is of high importance. Recently, physical layer security has been intensively investigated as an extra layer of protection for wireless communications. Directional modulation (DM) has been proposed as a mean to implement physical layer security. Antenna subset modulation (ASM) is a low complexity single beam DM technique suitable for millimeter-wave communications. The small wavelengths nature of millimeter-wave band is exploited to equip a transmitter with a large antenna array, and by randomly choosing few elements of this array for transmitting a symbol, secure communication in a single direction is obtained. This paper provides a study for the performance of broadcasting multi-beams antenna subset modulation (MASM) in which it is desirable to broadcast data streams to different receivers. A statistical model has been driven, and the symbol error rate of MASM using QPSK and secrecy capacity are obtained. Simulation results show that ASM can be used efficiently for multidirectional broadcasting communication, while maintaining its inherent security.