POSTBC-OFDM with Sectorized Antenna Reception over Rapidly Time-Varying Channels

Pseudo-orthogonal space-time block coded OFDM system (POSTBC-OFDM) has recently been proposed as a novel scheme for the frequency-selective channel scenario. However, a general assumption underlying the use of space-time codes is that the channel should be quasi-static, which is violated from the nature of high mobility environment. Additionally, large Doppler spread causing rapidly time-varying channels could destroy the orthogonality among neighboring subcarriers and lead to intercarrier-interference (ICI). This paper studies the extension of the POSTBC-OFDM scheme to the rapidly time-varying channel case by adopting sectorized antenna reception technique which could reduce Doppler spread and the channels time-variance by restricting the incident angle of imping waves to a finite range. Simulation results show that this proposed system is not only suitable for high mobility condition, but also can get a better tradeoff among performance, code rate and complexity of receiver.