Differential Transmission Schemes for Generalized Spatial Modulation

TL;DR

This paper introduces two novel differential spatial modulation schemes that activate multiple antennas simultaneously, achieving higher spectral efficiency and better error performance with fewer antennas and lower modulation order.

Contribution

The paper proposes two new differential schemes for spatial modulation that improve spectral efficiency and error performance compared to traditional methods.

Findings

Higher spectral efficiency with fewer antennas

Better bit error rate performance than traditional schemes

Union bound analysis confirms robustness at medium to high SNR

Abstract

Differential modulation schemes are very relevant in receivers having power and processing limitations, as these schemes dispense with the need for knowledge of channel coefficients for symbol detection. Spatial modulation (SM) is a scheme used in multi-antenna transmission scenarios where the data is transmitted in the amplitude, phase and spatial domains through selected antennas. In the coherent domain, generalized SM (GSM) employs multiple antennas in combination during every time slot to enhance the spectral efficiency (SE). In this paper, we propose two differential schemes which activate two or more antennas at a time to transmit the modulated symbol. These schemes achieve higher SE using a lesser number of antennas and lower order modulation schemes instead of the higher number of antennas required for conventional SM schemes based on differential modulation. Simulation studies reveal that the proposed schemes have better bit error rate performance than traditional differential SM schemes. We also derive the analytical union bound for the proposed schemes and is satisfied from medium to high signal-to-noise ratio (SNR) ranges.