摘要
为了解决低信噪比直扩信号扩频码的盲估计问题,提出了一种直扩信号的协方差矩阵累加平均和离散卡洛(Karhunen-Loève,K-L)变换的方法。该方法是在已知直扩信号的扩频码周期、码速率等参数的前提下,将接收到的直扩信号以一随机确定值为起点进行周期分段以形成连续多个观察向量,求协方差矩阵并累加平均,实施离散K-L变换以得到信号所含主成分,由主成分特征向量估计观察信号的扩频码。而后对观察信号进行解扩处理,从而实现直序扩频信号的盲解扩处理。理论分析和数值结果表明了该方法非常鲁棒不易受噪声影响,在通常情况下可以工作于低于-20dB信噪比的环境下。
An approach was developed using covariance matrix accumulation and the Karhunen-Loève (K-L) transformation for DS/SS signals to blindly estimate the pseudo noise (PN) sequence in low signal to noise ratio (SNR) DS/SS signals. The parameters of the DS/SS signals (such as the period and chip interval of the PN sequence) need to be known. The received signals were divided into vectors based on the PN sequence period with the starting point of the division being randomized points uniformly distributed in a PN sequence period. Then the covariance matrix of the signal vectors was analyzed using the K-L transformation. The PN sequence of the DS/SS signals was then blindly estimated from the main component eigenvector. The estimated PN sequence can be used to calculate the DS/SS signal despreading without the PN sequence. Theoretical analyses and test results show that the approach is very robust, working well on SNR below -20 dB in normal circumstances.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2005年第1期48-51,84,共5页
Journal of Tsinghua University(Science and Technology)
基金
清华大学深圳研究生院博士后基金资助项目(023100012)
