Reduced-Complexity Iterative-Detection-Aided Generalized Space-Time Shift Keying

A novel reduced-complexity soft decision (SoD)-aided detector is proposed for the recent concept of space-time shift keying (STSK), where the detector´s achievable performance is capable of closely approaching that of the optimal maximum a posteriori (MAP) detector. More specifically, we exploit a hybrid combination of the modified matched filtering concept and of reduced-complexity exhaustive search for the sake of reducing the MAP detector´s decoding complexity. Furthermore, we extended this detector to support the class of generalized STSK (GSTSK) scheme that subsumes diverse multiple-input-multiple-output (MIMO) arrangements. The proposed reduced-complexity SoD-aided GSTSK detector also attains significantly lower complexity than the MAP detector while imposing only marginal performance degradation, which is in the range of 1-2 dB. As an optional means of further reducing complexity, the Markov Chain Monte Carlo (MCMC) algorithm is invoked for the proposed GSTSK detector. Our EXtrinsic Information Transfer (EXIT) chart analysis reveals that the proposed STSK detector is capable of closely approaching the optimal performance, whereas the GSTSK detector advocated exhibits a modest performance gap with respect to the max-log MAP detector.