Cooperative Spectrum Sensing under Noise Uncertainty in Cognitive Radio

Spectrum sensing is the key technology in Cognitive Radio (CR) for primary user detection. Noise uncertainty in spectrum sensing will make the detector unreliable due to "SNR walls". In this paper, cooperative spectrum sensing with adaptive thresholds is proposed to improve the detection performance under noise uncertainty. In this algorithm, each secondary user will use a two-thresholds detector for local detection. The thresholds are chosen according to the noise uncertainty at each secondary user. After each detection, the detection results are fused to give the final decision. Computer simulation indicates that our proposed algorithm is robust to the changes of noise uncertainties at secondary users. It can achieve better performance than cooperative spectrum sensing with one threshold or two fixed thresholds when the noise uncertainties are not equal at each secondary user.