频谱感知技术是认知无线电实现的关键,对解决频谱资源匮乏的问题起着举足轻重的作用,因此受到业界的广泛关注。在分析比较了三种常见的频谱检测技术后,提出了一种在未知噪声下的基于小波包变换的能量检测算法,通过小波包变换对噪声和信号功率进行估计从而得到较为准确的判决门限。仿真结果显示,在未知噪声情况下的该算法具有较好的鲁棒性,有望成为适于认知无线电应用的频谱感知技术。 Spectrum sensing technology is the key to the realization of cognitive radio and plays a decisive role in solving the problem of lack of spectrum resources. Therefore, it is widely concerned by the industry. After analyzing and comparing three common spectrum detection techniques, an energy detection algorithm based on wavelet packet transform with unknown noise was proposed. By using wavelet packet transform, the noise and signal power were estimated to obtain a more accurate threshold. Simulation results show that the proposed algorithm is robust in the presence of unknown noise and is expected to become a spectrum sensing technology suitable for cognitive radio applications.