Spectrum Loading Type Dynamic Spectrum Allocation Technique for Cognitive Radio Systems

This paper proposes a spectrum loading type dynamic spectrum control technique for broadband cognitive radio systems. In the proposed scheme, based on the detection of available spot-wise spectra, discrete spectrum components of a framed symbol sequence are mapped onto the spot-wise spectra. Two spectrum mapping schemes are proposed; single-RF scheme in which available spot-wise spectra are located so close that the entire spot-wise spectra can be covered by an FFT/IFFT with a reasonable number of FFT points, and multi-RF scheme in which the spot-wise spectra are located far away so that the entire spectra cannot be covered by an FFT/IFFT processor. Computer simulation confirms that the proposed scheme is effective in utilizing spot-wise spectra. Moreover, the proposed scheme is confirmed to be effective in enhancement of co-channel and inter-symbol interference immunity when the number of opportunistically available spot-wise spectra is increased.