Comparative study of turbo coded wideband adaptive modulation and space-time trellis codes

The decision feedback equaliser (DFE) aided turbo coded wideband adaptive quadrature amplitude modulation (AQAM) is capable of accommodating the temporal channel quality variation of fading channels. By contrast, the family of multiple-input-multiple-output (MIMO) DFE aided space-time trellis codes benefits from transmit diversity and hence it is capable reducing, rather than accommodating the temporal channel quality fluctuations. The performance of both systems is characterised and compared when communicating over the COST 207 typical urban (TU) wideband fading channel. It was found that the turbo coded AQAM scheme outperforms the two-transmitter space-time trellis coded (STTC) system employing two receivers, although its performance becomes inferior to that of a STTC arrangement employing more than two receivers.