Pilot-symbol-aided channel estimation for OFDM in wireless systems

摘要

In this paper, we investigate pilot-symbol-aided parameternestimation for orthogonal frequency division multiplexing (OFDM)nsystems. We first derive a minimum mean-square error (MMSE)npilot-symbol-aided parameter estimator. Then, we discuss a robustnimplementation of the pilot-symbol-aided estimator that is insensitivento channel statistics. From the simulation results, the requirednsignal-to-noise ratios (SNRs) for a 10% word error rate (WER) are 6.8 dBnand 7.3 dB for the typical urban (TU) channels with 40 Hz and 200 HznDoppler frequencies, respectively, and they are 8 dB and 8.3 dB for thenhilly-terrain (HT) channels with 40 Hz and 200 Hz Doppler frequencies,nrespectively. Compared with the decision-directed parameter estimator,nthe pilot-symbol-aided estimator is highly robust to Doppler frequencynfor dispersive fading channels with noise impairment even though it hasnsome performance degradation for systems with lower Doppler frequencies