Comparative studies of space-time block codes and fading-resistant modulations in Rayleigh fading channels.

摘要

Space-time block codes (STBC) [8] and fading-resistant modulations (FRM) [15], [14] are compared in frequency-flat Rayleigh fading environments in terms of their performance criteria, design methods, bit-error-rate (BER) performance and receiver complexity. We show that both schemes can be represented by a general transmission model and they have the same performance criteria. However, each scheme maximizes these criteria by using different design methods. When four transmit antennas and complex constellions are used, an FRM has better BER performance than an STBC. However, receiver complexity of the FRM is higher.; Next, we propose a multiple-input-multiple-output (MIMO) decision-feedback equalizer (DFE) for the reception of FRM signals in frequency-selective fading environments. A new decision rule is proposed for this MIMO-DFE due to the characteristics of FRM signals. If two transmit antennas and 4-QAM constellations are used, a MIMO-DFE for the FRM has less complexity than that of the STBC.