DFT-modulated filterbank transceivers for multipath fading channels

The orthogonal frequency division multiplexing (OFDM) transceiver has enjoyed great success in many wideband communication systems. It has low complexity and robustness against multipath channels. It is also well-known that the OFDM transceiver has poor frequency characteristics. To get transceivers with better frequency characteristics, filterbank transceivers with overlapping-block transmission are often considered. However these transceivers in general suffer from severe intersymbol interference (ISI) and high complexity. Moreover costly channel dependent post processing techniques are often needed at the receiving end to mitigate ISI. We design discrete Fourier transform (DFT) modulated filterbank transceivers for multipath fading channels. The DFT modulated filterbanks are known to have the advantages of low design and implementation cost. Although the proposed transceiver belongs to the class of overlapping-block transmission, the only channel dependent part is a set of one-tap equalizers at the receiver, like the OFDM system. We show that for a fixed set of transmitting or receiving filters, the design problem of maximizing signal-to-interference ratio (SIR) can be formulated into an eigenvector problem. Experiments are carried out for transmission over random multipath channels, and the results show that satisfactory SIR performance can be obtained.