Automatic suppression of narrow-band interference in direct-sequence spread-spectrum systems

This paper addresses the problem of narrow-band interference (NBI) cancellation in direct-sequence spread-spectrum systems. The proposed procedure amounts to a preliminary nonlinear processing, wherein, upon projection of the received signal onto a Fourier basis, a number of samples having the largest modula are excluded from further processing. The structure of the optimum detector operating on censored observations is obtained, showing that the optimum detector performs matched filtering on the censored data. The performance assessment demonstrates that this receiver is able to suppress narrow-band interferers, no matter what their structure, provided that the censoring depth is properly chosen. A blind version of such a receiver is presented also, and a comparative performance assessment demonstrates that, unlike other suppression procedures, the proposed system allows suppression of NBI with no prior knowledge on its structure.