Improved transmit diversity block coded OFDM systems for highly dispersive channels

Abstract

In 2000, King proposed two g/sub 2/-based transmit diversity block coded OFDM (TDBC-OFDM) systems, i.e., space-time block coded (STBC-OFDM) and space-frequency block coded OFDM (SFBC-OFDM). However, he employed the least square (LS) detector, which was designed under the assumption that the channel is static over the duration of a space-time/frequency codeword. Thereupon, STBC-OFDM/SFBC-OFDM suffers from highly time-frequency selectivity of the channel. Recently, Antony recommended three novel detectors for space-time block coding (STBC) to combat the rapid channel variation. In our work, these detectors are applied to improve the original g/sub 2/-based TDBC-OFDM systems. Also, the performances of the improved g/sub 2/-based TDBC-OFDM systems are evaluated by computer simulation. Simulation results have revealed that significant performance improvement can be achieved even when the systems are operated in highly dispersive channels.