Reconfigurable discrete Fourier transform filter banks for multi-standard channelizers

In a wireless communication receiver, channelization is the process of extracting individual narrowband radio channels from the digitized wideband input signal and providing these channels at baseband for further processing. Discrete Fourier transform filter banks (DFTFBs) are widely employed for the channelization purpose. This is because they efficiently utilize the polyphase decomposition of the prototype filter so that the prototype filter can be operated at a significantly reduced sampling rate. However DFTFBs suffer from the drawback that they can be employed only for the extraction of channels of uniform bandwidths. In this paper, a new DFTFB is presented which can be reconfigured with minimal overhead to extract channels of different bandwidths. The proposed DFTFB consists of a prototype filter which employs the concept of coefficient decimation for obtaining different passband widths. From the analysis of the architecture, it is clear that the overhead in the proposed filter bank is only few extra adders when compared to the conventional uniform DFTFB. Implementations results show that the proposed filter bank offers area and power reductions of 54% and 42% and speed improvement of 30.5% over conventional DFTFB respectively.