Cooperative spectrum sensing and signal detection in cognitive radio

Cognitive radio (CR) is expected to be the key enabling technology for increased spectrum utilization. As primary user activity is not spatially localized, a collaborative measure amongst multiple cognitive radio nodes has been suggested as a more accurate model of activity. This scheme was proposed to combat noise fading and shadowing as well as improves the probability of detection by collaborating to detect primary user signal. This paper studies cooperative spectrum sensing and signal detection in cognitive radio system by implementing hard decision combining in data fusion centre. Through computer simulation, we evaluate the performances of cooperative signal detection by employing OR and AND rules as decision combining. Energy detector is used to observe the presence of primary user signal. The results are compared to non-cooperative signal detection for evaluation. They show that greater than 10 dB of SNR and 15 collaborated users in cognitive radio system is optimal value for probability of detection.