Flexible Low Complexity Uniform and Nonuniform Digital Filter Banks with High Frequency Resolution for Multistandard Radios

Multistandard radios typically employ digital filter banks (FBs) for channelization of wideband input signals consisting of multiple radio channels corresponding to different wireless communication standards. In this paper, we propose a new design technique to obtain uniform as well as nonuniform digital FBs for multistandard channelization. In the proposed FB design technique, the improved coefficient decimation method (ICDM) is used to obtain different low-pass, high-pass, and multiband frequency responses using a single low-pass prototype filter. These frequency responses are algebraically operated upon using appropriate spectral subtraction, complementary filter response operation, and frequency response masking operations to obtain the desired sub-bands in the FB. With the help of suitable design examples, we show that our FB is a low complexity and flexible alternative to the other digital FBs in the literature, in both uniform and nonuniform channelization scenarios. The proposed ICDM-based FB is shown to be able to achieve a higher number of distinctly located sub-bands with twice the center frequency resolution when compared with the discrete Fourier transform-based FB (DFTFB) and the conventional coefficient decimation method-based FB (CDFB). For a uniform channelization design example for wireless communications, implementation results show that the proposed ICDM-based FB achieves 70.92% and 15.49% reductions in resource utilizations and 58.72% and 23.13% reductions in power consumptions when compared with the DFTFB and CDFB respectively. Also, for a nonuniform channelization design example for wireless communications, the proposed ICDM-based FB shows an 11.46% reduction in multiplication complexity when compared with the CDFB.