Very Low Complexity Variable Resolution Filter Banks for Spectrum Sensing in Cognitive Radios Using Multi-Stage Coefficient Decimation

Conventional filter bank-based spectrum sensing methods employ uniform discrete Fourier transform filter bank (DFTFB). In this paper, we propose a multi-stage coefficient decimation filter bank (MS-CDFB) that can provide variable sensing resolution for wideband spectrum sensing in cognitive radios. From an initial fixed-coefficient modal filter, a filter bank that has multiple passbands of different passband widths can be obtained using coefficient decimation. Design examples show that the multiplication complexity of the proposed MS-CDFB is about one-seventh of that of the DFTFB. Furthermore, MS-CDFB does not have the overhead of DFT computation that exist in DFTFB. The proposed very low complexity MS-CDFB offers better sensing accuracy compared to that of the DFTFB.