摘要： 为提高能量检测算法的性能,提出一种基于全相位快速傅里叶变换(FFT)的频谱感知算法。全相位FFT中的数据预处理过程,考虑了数据段中心样本点所有可能组合的情况,从而减少因信号截断所导致的频谱泄露,提高谱分析精确度。以能量检测法为例,通过Matlab 对基于传统FFT 和全相位FFT 的频谱感知算法进行理论分析和仿真,结果表明,在信噪比相同的条件下,后者的谱间干扰较小,信号的误检率较低;在相同虚警率的条件下,后者可使频谱泄露得到有效抑制,获得的频谱更接近于真实的频谱信息,检测概率相应提高。因此,全相位FFT 能量检测法的检测性能明显优于传统能量检测法。

关键词: 认知无线电, 频谱感知, 频谱泄露, 全相位快速傅里叶变换, 能量检测, 检测概率

Abstract: To improve the performance of energy detection algorithm,a new spectrum sensing algorithm based on allphase Fast Fourier Transform(FFT) is proposed. Considering all possible combination cases of the data segment central sample points,the data preprocessing of all-phase FFT can reduce spectral leakage caused by data truncation and improve the accuracy of spectral analysis. Taking energy detection as an example, by Matlab, spectrum sensing based on conventional FFT and all-phase FFT are respectively carried out in terms of theoretical analysis and simulation. The simulation results show that under the same SNR,spectral interference of the latter is smaller,so as to reduce the probability of false detection. At the same false alarm rate,the latter’s probability of detection is bigger. Because spectral leakage is effectively suppressed,the spectrum information obtained is closer to the real one. Therefore,the performance of all-phase FFT energy detection algorithm is better than the conventional energy detection algorithm.

Key words: Cognitive Radio (CR), spectrum sensing, spectrum leakage, all-phase Fast Fourier Transform ( FFT), energy detection, detection probability

中图分类号: 

• TN911. 23