A High Spectral Efficiency Generalized Spatial Modulation Scheme for MIMO Fading Channels

The Multiple–antenna technique called MIMO (Multiple-Input-Multiple-Output) constitutes a key technology for modern and future wireless communications, which trade– off superior error performance and higher data rates for increased system complexity and cost. As an extension to the classical MIMO schemes, a novel technique called Spatial Modulation(SM) can even enhance the capability of MIMO systems by exploiting the index of the transmit antenna(TA)s to convey information bits. In this paper, a Generalized SM MIMO (GSM MIMO) scheme is proposed, which uses more than one active antennas for each transmission. Parallel signal symbols are transmitted simultaneously on each of the active antennas per channel use (pcu). Most importantly, distinct combinations of active antennas can also be used to convey information symbols. In this proposed scheme, the number of transmit antennas can be an arbitrary positive integer greater than one, while eliminating the limit on TA number as in original SM MIMO. And the spectrum efficiency (SE) can be much higher than SMX schemes like V-BLAST. A suboptimal MMSE-based detection algorithm is also proposed to reduce the high complexity of the optimal Maximum-Likelihood (ML) detector. The performance of the proposed scheme is evaluated in an uncorrelated Rayleigh flat fading channel through Monte-Carlo simulations. Keywords-Multiple Antennas; Multiple Input Multiple Outout(MIMO) systems; Spatial Modulation(SM);Generalized SM(GSM)