Spatial Diversity-Achieving Quadrature Spatial Modulation

Quadrature space modulation (QSM) was viewed recently as a viable multiple-input multiple-output (MIMO) communication technique for next generation wireless system. In this paper, the new scheme achieving spatial diversity of QSM system called SDA-QSM is designed. Through this design, which exploit the degrees of freedom in the spatial domain from the transmit antennas, the real part of a modulated symbol is transmitted by more than one activating antenna in in-phase domain of the transmitted spatial vector (TSV). Similarly, the imaginary part of the modulated symbol is transmitted by more than one activating antenna in quadrature domain of the TSV. Furthermore, the number of antennas does not need to be proportional to the power of 2 due to the property of antenna index modulation of activating multiple antennas and can transmit more extra information bits. Finally, data rate, the squared minimum Euclidean distance compared with other schemes and an upper bound on the average bit error probability (ABEP) are elaborately analyzed. Simulation results using Monte Carlo demonstrate that the proposed SDA-QSM system has better bit error ratio (BER) performance compared with the conventional QSM system in wireless network.