Spatial modulation: optimal detector asymptotic performance and multiple-stage detection

Spatial modulation (SM) is a recent multiple-input multiple-output transmission technique, which entirely avoids inter-channel interference as well as the need for transmit antenna synchronisation. The first objective of this study is to present an asymptotic bound to quantify the average bit error rate (BER) performance of M-ary quadrature amplitude modulation (M-QAM) SM with optimal-based detection over independent and identically distributed Rayleigh flat fading channels. The analytical frameworks are validated by Monte Carlo simulation results, which show that the derived lower bounds are increasingly tight for large signal-to-noise ratio values. The second objective is to introduce a novel SM detection scheme, termed multiple-stage (MS) detection. Performance and complexity comparisons with existing SM detectors show two main benefits of MS detection: near-optimal BER performance and up to a 35% reduction in receiver complexity as compared to the maximum likelihood-based SM detector.