Non-cooperative Case, Direct Spread-spectrum Signal Spreading Code Blind Estimation

Because of the Low-Probabilities-of-Intercept (LPI) property, Direct Sequence Spread Spectrum (DS/SS) signal is difficult to be detected and discriminated in non-cooperative context. In order to intercept the DS/SS signal, more and more researches are being done on the blind estimation of the Pseudo Noise (PN) sequence of DS/SS signal. The main works done by this paper are:1. Introduce the theory of blind estimation of PN sequence of single DS/SS signal in and abroad the country, like Massey algorithm, Principle Component Analysis (PCA) and Triple Correlation Function (TCF).2. Invent a new idea of blind synchronization based on the theory of PCA to solve the problem of blind estimation of PN sequences of multiple DS/SS signals.3. Extend the theory of Triple Correlation Function to estimate the PN sequences of multiple DS/SS signals, and invent a way to eliminate the influence of modulation.4. Invent a new idea of Combining Independent Component Analysis (ICA) and Massey algorithm to blindly estimate PN sequences of DS-CDMA signal.