Date Added: Aug 2012
A cognitive radio is a transceiver which automatically detects available channels in wireless spectrum and accordingly changes its transmission or reception parameters so more wireless communications may run concurrently in a given spectrum band at a place. The key requirement in cognitive radio is accurate detection of vacant spectrum bands. In this paper, an energy detector based on Tree structure Quadrature Mirror Filter Bank (TQMFB) is proposed for detecting the centre frequencies of the channels(frequency bands).It is found that as the value of FFT size increases, the error in estimation decreases for smaller window sizes and does not change significantly for larger windows. Simulation results show that the proposed method estimates the centre frequency of channel with high accuracy and low SNR.