Space-Time Block Codes with Symbol-by-Symbol Maximum Likelihood Detections

This paper presents a new set of quasi-orthogonal space-time block codes (QOSTBCs) with symbol-by-symbol maximum likelihood (ML) detections for four transmit antennas over quasi-static Rayleigh fading channels. Each of them is analytically proved to achieve full diversity and the same coding gains as the coordinate-interleaved orthogonal design by individually using their optimal constellation rotations over arbitrary QAM or 4M-PSK constellations. Previous designs are included in our systematic formulation as well. Together with the simulation results, the coding loss paying for simplifying the optimal decoders from complex symbol pairwise to symbol-by-symbol ML detections is found asymptotically equal to 0.21 dB, for the QOSTBCs achieving full diversity and the optimal coding gains over general QAM constellations.