一种DSSS信号载频与码片速率的估计方法

A Method of the Carrier Frequency and the Chip Rate Estimation for DSSS Signals

在军事通信领域中,为解决抗干扰问题,直接序列扩频(Direct Sequence Spread Spectrum,DSSS)信号具有较低的功率谱密度,信号淹没在背景噪声中,侦查难度较大。针对低信噪比DSSS信号载频与码片速率检测的难题,为提高通信系统的性能,消除噪声,利用循环统计量的循环特性可以体现出循环平稳信号的频率参数,高阶循环累积量可以有效地抑制任何平稳噪声与非平稳高斯有色噪声的特点,提出了一种可同时对DSSS信号的载频与码片速率进行盲估计的方法。通过对不同延时切片的选择可以实现低信噪比DSSS信号载频与码片速率的检测,不需要任何的先验信息,在低信噪比的情况下有较好的估测效果。仿真实验验证了估计方法有效性。

Due to its low power spectral density,the direct sequence spread spectrum signal is always submerged into the background noise and difficult to be reconnoitered.Based on the cyclic-character of cyclic-cumulants which can embody the frequency of cyclic stable signals and the high-order cyclic-cumulants which can suppress the stationary and non-stationary Gaussian coloured noise,a method of estimating the carrier frequency and the chip rate for the direct sequence spread spectrum signal is proposed.It can solve the difficult problem to estimate the carrier frequency and the chip rate.This method can achieve estimation by choosing different delay slices on the condition of low SNR（signal noise ratio）.This proposed method can perform blind detection without the prior knowledge of the signal on the condition of low SNR.The validity of this method is shown by the computer simulation.