Double Threshold Soft Decision Rule for Improving Performance of Cognitive Radio Networks

We propose an efficient soft decision rule to enhance the detection of unused spectra and to improve cognitive radio (CR) throughput. The performance of this rule is evaluated for additive white Gaussian noise and Rayleigh fading channels and compared with the square law and maximal ratio combining rules. For a signal to noise ratio (SNR) of 2dB, the proposed rule enhances the probability of a false alarm by 68% and 95% respectively in case of additive white Gaussian noise and by 53% and 92% in case of Rayleigh fading channels. The simulation results also show that the proposed method enhances throughput compared to the other rules. Over Rayleigh fading channels, throughput is enhanced by 210% compared to square law combining rule and 40% compared to the maximal ratio combining rule.