Approach to Blind Estimation of Lower SNR Long Code DS Signals
Zengshan Tian, Zhengzhong Zhou · Signal Processing · 2008
In this paper,we propose an approach of correlation matrix accumulation and eigen-analysis for long code DS signals, which can estimate the lower signal to noise ratios(SNR)long code DS signals blindly.Of course,the parameters of the long code DS signals(such as period and chip interval of the PN sequence)need to be known.We divide the received signals into vectors according to the period of PN sequence,and the start point of division is a randomized certain point uniformly distributed in a period of PN se- quence.Then we calculate and accumulate the correlation matrix of signal vectors,and compute its eigen-analysis.We can estimate the variance of noise in signals,signal to noise ratios and the start point of division from the eigenvalues of the correlation matrix,furthermore we can estimate the PN sequence of long code DS signals from the main component eigenvector blindly.Based on the estimated PN se- quence,we can realize the long code DS signals despreading without the PN sequence.The theoretic analysis and experimental results show that the approach is very robust,it can work well on lower SNR input signals under common circumstances.