基于循环前缀相关性的OFDM调制识别算法

针对多径衰落信道下正交频分复用(OFDM)与单载波信号之间调制识别难的问题,提出了一种OFDM与单载波信号调制分类的新方法.该方法首先通过对信号的自相关进行能量归一化并取绝对值,去除抖动、频偏和相位噪声的影响,然后对能量归一化自相关进行形态学滤波,减少由于信号观察长度有限和背景色噪声所产生的影响,提取经过处理后信号自相关的次峰值作为识别特征,最后设计基于支持向量机的分类器,实现了对OFDM与单载波信号之间的调制分类.实验仿真结果表明,该方法在多径衰落信道下具有稳健的识别性能.

Modulation Recognition of OFDM Based on the Correlation Property of the Cyclic Prefix

Considering that the modulation identification between orthogonal frequency division multiplexing(OFDM) and the single carrier signals is difficult in the multipath fading channel,a novel method for modulation classification between OFDM and the single carrier signals is proposed.Firstly,the autocorrelation of the signals is normalized by the energy and used with the absolute value to remove the scale problem and the impact of the frequency offset and the noise of the phase.Secondly,morphologic filtering is used to suppress colored-background noise effectively,and the second peak of the autocorrelation of the signal is picked up as the recognition characteristic.Lastly,the classifier based on the support vector machine is designed and the OFDM and the single carrier signals are classified.Simulation results show that the method achieves robust performance in the multipath fading channel.