Antenna Subset Modulation for secure millimeter-wave wireless communication

This paper exploits the potential of large antenna arrays at millimeter-wave (mm-Wave) frequencies to develop a low-complexity directional modulation technique, Antenna Subset Modulation (ASM), for point-to-point secure wireless communication. The main idea in ASM is to modulate the radiation pattern at the symbol rate by driving only a subset of antennas in the array. This results in a directional radiation pattern that projects a sharply defined constellation in the desired direction and randomizes the constellation in other directions. To implement ASM, a simple antenna selection technique that selects an antenna subset randomly for every symbol is proposed. While randomly switching antenna subsets does not affect the symbol modulation for a desired receiver along the main direction, it effectively randomizes the amplitude and phase of the received symbol for an eavesdropper along a sidelobe. Statistical analysis and numerical examples are presented to highlight the superior performance and secrecy capacity achieved by ASM.