Noise Predictive Turbo Equalization for a Filter Bank Based Receiver in a SC Transmission System

For coded transmission over band-limited channels with inter-symbol interference, Douillard proposed the turbo equalization approach which has been studied widely. It is an iterative equalization/decoding algorithm and results in tremendous performance improvement. This paper studies a turbo equalization approach, which includes our recently proposed filter bank based frequency-domain equalizer, and a noise predictor inside of a decision-feedback loop, in coded single-carrier transmission. Its performance is simulated in a frequency-selective channel for QPSK and 16-QAM modulations. Different number of iterations and noise prediction orders are examined. The simulation shows that one iteration with 5-taps noise prediction filter is sufficient to obtain significant gain over linear equalizer.