认知无线电技术是当前缓解频谱资源紧张的有效解决方案，频谱感知是认知无线电的关键技术，其中，能量检测是经典的频谱感知算法，对于研究频谱感知的初学者来说比较重要。-Cognitive radio technology is an effective solution to alleviate the tension of spectrum resources. Spectrum sensing is the key technology of cognitive radio. Among them, energy detection is a classical spectrum sensing algorithm, which is important for the study of spectrum-aware beginners.