A new blind adaptive interference suppression scheme foracquisition and MMSE demodulation of DS/CDMA signals

摘要

We present an efficient blind algorithm for estimating the codentiming of a desired user in an asynchronous direct-sequencencode-division multiple-access (DS/CDMA) system overnfrequency-nonselective-fading channels. The proposed algorithm acquiresnthe code timing explicitly and results in a near-far resistant minimumnmean-squared error (MMSE) demodulation without requiring the knowledgenof the timing information, amplitudes, and transmitted symbols of allntransmissions. The only required knowledge is the information of thensignature sequence used by the desired transmission. Several computernsimulations are done for additive white Gaussian channels, Rayleighnfading channels, and two-ray Rayleigh fading multipath channels,nrespectively. Numerical results show that the new algorithm is near-farnresistant to the multiple-access interference (MAI) in the DS/CDMAnsystem