LOS millimeter-wave communication with quadrature spatial modulation

Capacity analysis for line-of-sight (LOS) millimeter-wave (mmWave) quadrature spatial modulation (QSM) multiple-input multiple-output (MIMO) system is presented in this paper. QSM is a new MIMO technique proposed to enhance the performance of conventional spatial modulation (SM) while retaining almost all its inherent advantages. Furthermore, mmWave utilizes a license-free wide-bandwidth spectrum and is a very promising candidate for future wireless systems. Detailed and novel analysis of the mutual information and the achievable capacity for mmWave-QSM system are presented in this study. The conditions under which theoretical capacity can be achieved are derived and discussed. Monte Carlo simulation results are provided to corroborate derived formulas. It is shown that significant performance enhancements can be achieved under different system and channel configurations.