Filter Bank Based Frequency-Domain Equalization with Noise Prediction

Complex modulated filter bank (FB) based frequency-domain equalization (FDE) provides an attractive single-carrier scheme for broadband wireless communications. With mildly frequency selective subband processing and modest number of subbands, it is able to provide better performance than the conventional FDE with FFT due to the lack of guard-interval overhead. Another significant benefit of this approach is that the same filter bank can be utilized to implement significant part of the receiver channel selectivity in a flexible way. This paper studies a hybrid frequency-time domain equalizer, which utilizes FB based equalizer for the feedforward part and a noise predictor (NP) for the feedback. The motivation is that the feedforward and feedback filter can be designed separately, in contrast to a conventional decision-feedback equalizer (DFE). The performance can be adjusted by the order of the NP. A significant advantage of NP based equalizer, over the traditional DFE, is that it is easier to include error control decoding in the equalizer feedback loop. This is able to provide significant performance enhancement over the DFE structure where the decoding is after the feedback loop