Abstract: In cognitive radio systems, cognitive users need to accurate determine the using of the spectrum by real-time.Studying the performance detection of energy detection, it was found that the larger the noise fluctuations, the sharper the decline in performance of energy detection, especially in low SNR. We used the maximum fluctuations range of the noise uncertainty to amend the energy detection and gave a joint detection of the difference value and the energy which utilize the alteration of the difference value in the every energy detection to amend the judgment result and get the blending final result based on it. Simulation results show that under guaranteeing the advantage of the traditional energy detection the performance of our new energy detection can effectively improve the cognitive users accurate detection per- formance of spectrum usage in real-time.

Key words: Cognitive radio, Spectrum sensing, Energy detection, Noise uncertainty, Difference value