Implementing physical layer security using transmitters with constellation shaping

In wireless communication systems privacy among users contents is a crucial security requirement such as power and spectral efficiency. Spectral and power efficiencies are attainable with power efficient transmission schemes where constellations are decomposed into several BPSK (Bi Phase Shift Keying), being each one amplified and transmitted independently by an antenna. Besides that, due to constellation shaping on the desired transmission direction performed by these transmitters, some kind of physical layer security is assured as well. Under this approach, security is achieved by constellation shaping of the transmitted constellation since each user must know the transmitter configuration parameters associated to the constellation shaping, i.e., the direction in which the constellation is optimized, otherwise the received data would be meaningless. Commonly, security is assured by encrypted algorithms implemented by higher layers, such as private and public encrypted keys. However, system security can be improved with physical layer security schemes since they can be complemented with other security schemes from higher layers. Simulation results show the effectiveness of the proposed approach.