Channel estimation for OFDM systems with transmitter diversity in mobile wireless channels

Transmitter diversity is an effective technique to improve wireless communi cation performance. In this paper, we investigate transmitter diversity usi ng space-time coding for orthogonal frequency division multiplexing (OFDM) systems in high-speed wireless data applications. We develop channel parame ter estimation approaches, which are crucial for the decoding of the space- time codes, and we derive the MSE bounds of the estimators. The overall rec eiver performance using such a transmitter diversity scheme is demonstrated by extensive computer simulations. For an OFDM system with two transmitter antennas and two receiver antennas with transmission efficiency as high as 1.475 bits/s/Hz, the required signal-to-noise ratio is only about 7 dB for a 1% bit error rate and 9 dB for a 10% word error rate assuming channels w ith two-ray, typical urban, and hilly terrain delay profiles, and a 40-Hz D oppler frequency. In summary, with the proposed channel estimator, combinin g OFDM with transmitter diversity using space-time coding is a promising te chnique for highly efficient data transmission over mobile wireless channel s.