基于四阶累积量的DSSS/QPSK信号检测方法研究

The Study on the Detection Methods of DSSS/QPSK Signal Based on the Fourth-Order Cumulants

根据高斯白噪声的四阶累积量恒为零这一特性,研究了DSSS/QPSK信号的四阶累积量,提出了基于四阶累积量不同切片c4x(0,0,0)、c4x(τ,τ,τ)、c4x(0,τ,τ)和c4x(0,0,τ)的时域和频域检测方法.仿真结果表明,频域检测方法性能优于时域检测方法;综合考虑检测性能和实现难度,基于c4x(0,0,τ)的频域检测方法最好,在虚警概率为1%,信噪比为-11dB时,检测概率仍可达到50%以上.没有引入大规模的矩阵运算,运算量小,易于实现.

According to the fact that the fourth-order cumulant of the Gaussian White Noise is equal to zero,the fourth-order cumulant of the DSSS/QPSK signal is studied and the time domain and frequency domain detection methods based on the fourth-order cumulant different slices c4x （0,0,0）, c4x（τ,τ, τ）. c4x（0, τ, τ） and c4x（0,0, τ） are proposed. Experimental results show that the detection performance of the method in frequency domain is better than that of the method in time domain. Trading off the detection performance and realization difficulty,the frequency domain detection method based on c4x（0,0, τ） is the best. When the false alarm probability is set to 1%,its detection probability reaches above 50% at SNR - 11dB.The proposed methods don＇ t involve extensive matrix operations, their computation complexities are low, and they are easy to implement.