On directional modulation: An analysis of transmission scheme with multiple directions

Increasing the spectral efficiency was always the motivation behind the evolution of wireless communication systems. Also, due to the widespread usage of wireless systems, securing the transmitted data rises as a main concern nowadays. Hereby, we introduce a scheme that increases the capacity of wireless systems by transmitting multiple independent data streams, while using the space domain as a source of separation. The scheme also utilizes the space domain, in order to provide a secure communication link for each of the transmitted streams. The analysis is performed by using different orders of QAM constellations, and also baseband orthogonal-frequency-division-multiplexing signal structure. The scheme shows a high randomization for the received signal along the directions out of the desired transmission beams, and fits to the standard bit-error-rate curves for all desired transmission directions. Besides, the scheme can be easily synthesized, using low complexity algorithms.