Time-domain equalizer for filter bank-based multicarrier communications

Filter bank-based multicarrier systems have two main advantages over the OFDM/DMT modulation method. Firstly, the bank selectivity is a design parameter for precise spectrum control. This provides resistance against narrowband interference and allows to use very narrow guard bands around the multicarrier signal. Secondly, the guard period applied in OFDM-systems to combat ISI becomes unnecessary. This saves some bandwidth for data transmission. However, efficient channel equalization techniques for such systems are still an active area of development. In this paper a cosine-modulated filter bank is used as a transmultiplexer, because these modulated transforms provide fast implementation structures. A time-domain equalizer is used to linearize the channel phase response before the receiver filter bank, whereas the amplitude response is corrected afterwards with a single multiplier per subchannel. Here we develop two simple ways to design an equalizer, assuming static channel conditions. The equalizer performance is then compared with a MIMO-combiner, and the pros and cons of both equalization principles are discussed