Decision Feedback Channel Estimation for OFDM with STTD

Abstract— In this paper, we propose decision feedback channel estimation (DFCE) for orthogonal frequency division multiplexing (OFDM) with space-time coded transmit diversity (STTD). Two transmit channels are simultaneously estimated by transmitting the STTD encoded pilot. To improve the tracking ability of the channel estimation against fast fading, decision feedback is also used in addition to pilot. For noise reduction and prevention of error propagation, the cascade of two averaging filters in timeand frequency-domain is applied. The average bit error rate (BER) performance of OFDM with STTD is evaluated by computer simulation. It is found that the use of DFCE can achieve a degradation in the Eb/N0 from ideal CE of as small as 2dB for an average BER=10. With receive antenna diversity reception, Eb/N0 degradation can be further reduced to as small as 1dB.