Frequency-Domain Channel Estimation and Tracking Schemes for Space-Time Coded OFDM Systems

Two channel estimation and tracking schemes for space-time coded orthogonal frequency division multiplexing (OFDM) systems are proposed in frequency domain. Since the processing are all made in frequency domain, the computational complexity of the proposed schemes is reduced dramatically compared with the time-domain scheme. The two proposed schemes both use STBC-pattern training symbols during the training period. During the data transmission period, the first proposed scheme use the decision-directed tracking algorithm, and the second proposed scheme use an iterative algorithm to track the channel variation. The two schemes both can improve the system performance, and the second scheme can bring more performance gain even with small iteration times. The performances of the proposed schemes are demonstrated by computer simulation in the typical indoor channel.