Performance of modified generalized quadrature spatial modulation over correlated fading channels with imperfect channel information

A generalized version of the quadrature spatial modulation (QSM) scheme is called a modified generalized QSM (mGQSM), which is proposed to enhance the spectral efficiency of QSM by considering multiple radio frequency chains. In QSM, the in-phase and quadrature dimensions are used to transmit the data symbols. Using the QSM transmission principle, the mGQSM scheme can transmit the data symbols on different antennas ranging from NC$$ {N}_C $$ to 2NC$$ 2{N}_C $$. Moreover, the proposed scheme provides an additional one bit data rate when compared to generalized QSM (GQSM). This paper presents the performance of mGQSM under imperfect channel conditions over correlated Rayleigh, Rician, and Nakagami-m fading channels. For the computer simulations, we assume beta=0.7$$ \beta =0.7 $$ and various fading parameters for the Rician and Nakagami channels. The error performances of the mGQSM, GQSM, and QSM schemes are evaluated using the maximum-likelihood (ML) detector. Under imperfect channel conditions, the mGQSM and QSM schemes are examined and compared. Furthermore, a low complexity ordered block minimum mean-squared error (OB-MMSE) detector is employed for the reduced-codebook mGQSM (RC-mGQSM), which achieves near-ML performance with reduced complexity.