Channel estimation for OFDM systems with transmitter diversity inmobile wireless channels

摘要

Transmitter diversity is an effective technique to improvenwireless communication performance. In this paper, we investigatentransmitter diversity using space-time coding for orthogonal frequencyndivision multiplexing (OFDM) systems in high-speed wireless datanapplications. We develop channel parameter estimation approaches, whichnare crucial for the decoding of the space-time codes, and we derive thenMSE bounds of the estimators. The overall receiver performance usingnsuch a transmitter diversity scheme is demonstrated by extensivencomputer simulations. For an OFDM system with two transmitter antennasnand two receiver antennas with transmission efficiency as high as 1.475nbits/s/Hz, the required signal-to-noise ratio is only about 7 dB for an1% bit error rate and 9 dB for a 10% word error rate assuming channelsnwith two-ray, typical urban, and hilly terrain delay profiles, and an40-Hz Doppler frequency. In summary, with the proposed channelnestimator, combining OPDM with transmitter diversity using space-timencoding is a promising technique for highly efficient data transmissionnover mobile wireless channels