Spectral detection with multistage granularity bands using filter bank techniques for CR applications

摘要

In this paper, we propose a method to detect unused spectrum using multistage Cosine Modulated Filter Bank (CMFB) technique for Cognitive Radio (CR) applications. The precision of spectral detection is increased when the number of sub-bands in the filter bank is increased, this increases the computational complexity of the filter bank structure. We suggest a multistage filter bank structure to reduce the computational complexity. Spectrum detection is done effectively in filter banks by proper choice of prototype filter with specified sub-band attenuation. The sub-bands detected in coarser granularity bands are sensed with finer granularity bands for precise spectral detection depending on the predefined threshold and probability of false alarm. The remaining sub-bands are not sensed further which in turn reduces the computational complexity. Through simulations it is shown that spectrum detection with multistage granularity bands maintains bandwidth efficiency and reliability in spectrum detection even at low SNR.