Improved Spatial Modulation for High Spectral Efficiency

TL;DR

This paper introduces a novel MIMO transmission scheme that combines spatial modulation and spatial multiplexing, significantly increasing spectral efficiency and outperforming existing methods like SM and V-BLAST in high SNR conditions.

Contribution

The paper proposes a new MIMO scheme that transmits multiple symbols simultaneously using multiple antennas, enhancing spectral efficiency beyond traditional spatial modulation.

Findings

Outperforms optimal SM and V-BLAST at high SNR.

Achieves 5dB and 7dB SNR improvements for 8 bits/s/Hz spectral efficiency.

Demonstrates effectiveness in uncorrelated Rayleigh fading channels.

Abstract

Spatial Modulation (SM) is a technique that can enhance the capacity of MIMO schemes by exploiting the index of transmit antenna to convey information bits. In this paper, we describe this technique, and present a new MIMO transmission scheme that combines SM and spatial multiplexing. In the basic form of SM, only one out of MT available antennas is selected for transmission in any given symbol interval. We propose to use more than one antenna to transmit several symbols simultaneously. This would increase the spectral efficiency. At the receiver, an optimal detector is employed to jointly estimate the transmitted symbols as well as the index of the active transmit antennas. In this paper we evaluate the performance of this scheme in an uncorrelated Rayleigh fading channel. The simulations results show that the proposed scheme outperforms the optimal SM and V-BLAST (Vertical Bell Laboratories Layered space-time at high signal-to-noise ratio (SNR). For example, if we seek a spectral efficiency of 8 bits/s/Hz at bit error rate (BER) of 10^-5, the proposed scheme provides 5dB and 7dB improvements over SM and V-BLAST, respectively.