A new blind adaptive beamforming algorithm based on decision feedback using pre-despreading signals is proposed in this paper.

The good convergence stability of the steepest decline CMA(SDCMA) and faster convergence of the least-squares CMA(LSCMA) in beam-forming applications is analyzed in this paper, to absorb the advantages of the both algorithms, a new combined blind beam-forming algorithm based on the pre-despread decision feedback(SD-LSCMA) is proposed.

A despread-demodulator for Direct-Sequence Spread-Spectrum(DS-SS)system is introduced.

Digital matched filter is used for despreading synchronization signals,and Costas loop is applied to obtain the demodulation signals,and then the original signal is resumed by the low-pass filter.

Direct sequence spread spectrum (DSSS) and despreading first structure is most advantageous of all kinds of spread spectrum techniques.

Three methods of NBI rejection have been discussed in this thesis, which are time-domain linear prediction adaptive algorithm, frequency-domain adaptive algorithm and adaptive de-spread spectrum re-spread spectrum (SS-SP) decision algorithm.

To utilize a few of matrix differential identities, in this paper, we establish the persolution and its derivative Sturm Comparability Theorem on two - order linear differential system(1 ) 1 and extend a number of classic results.