Crosscorrelation Cancellation in SS/DS Block Demodulator


IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E74-A   No.9   pp.2596-2602
Publication Date: 1991/09/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Issue on Information Theory and Its Applications)

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This paper shows direct-sequence spread-spectrum (SS/DS) block demodulator employing crosscorrelation canceller. The crosscorrelation cancellation can be realized by adding a matrix calculator in conventional SS/DS block demodulator. In the SS/DS block demodulator, PN-codes assigned to all SS/DS users can be detected by processing the received signal stored in memory recursively. Next the correlation values between PN-codes are calculated, and then the received signal is processed algebraically by the cancellation matrix composed of the correlation values. As a result, it can provide high capacity per unit bandwidth. The simulation results show that the capacity per unit bandwidth is around 45% when PN-code length is 127 chips (Process Gain = 21 dB) and input SNR is higher than -6 dB, and the good near-far resistance capability can be achieved.