Enhancing Spectral Efficiency and BER Performance of Spatial Modulation using Layered Architecture

The recent emergence of spatial modulation (SM) as a new modulation concept maneuvers the random and unique properties of the multiple-input multiple-output (MIMO) wireless channels. In this paper, an enhancement in SM scheme is proposed by innovative usage of quadrature amplitude modulation (QAM) to add layers which fully exploit both the signal and spatial domains. Layered spatial modulation (LSM) controls the preset rotated signals with normalized amplitudes to classify the layers and to identify the transmitted symbols at the transceiver by completely avoiding inter-channel interference (ICI). High spectral efficiency can be achieved with the addition of only one transmit antenna for each layer by the LSM scheme. Simulation results show that the proposed method has significant improvement in spectral efficiency and bit-error-rate (BER) performance as compared to other MIMO schemes.