Author(s)

Chunyan Bi, Yingying Chen

Corresponding Author

Chunyan Bi

Abstract

In order to solve the blind estimation problem of low signal-to-noise ratio DSSS spread spectrum codes, a method of covariance matrix cumulative averaging and discrete Karo hunen-Lo v e (K-L) transform of DS signals is proposed. The method is to periodically segment the received DS signal with a random determination value to form a continuous plurality of observation vectors on the premise of the parameters such as the spreading code period and the code rate of the known DS signal. The covariance matrix is summed and averaged, the discrete KL transform is implemented to obtain the principal component of the signal, and the spreading code of the observed signal is estimated by the principal component eigenvector. Then, the observation signal is despreaded, thereby implementing blind despreading processing of the direct sequence spread spectrum signal. Theoretical analysis and numerical results show that the method is very robust and is not susceptible to noise. Under normal circumstances, it can work in an environment with signal-to-noise ratio lower than - 20 dB.

Keywords

Low SNR, Long Pseudo Code, Spread Signal