Narrow-band interference suppression in spread spectrum communication with iterative decoding

It is known that the narrow-band interference rejection capability of a direct-sequence spread-spectrum system can be enhanced by suitably processing the received signal prior to correlating it with the PN sequence. These processing schemes include those based upon least-mean-square estimation techniques and those based upon transform domain processing structures. In this paper, soft output decoding is used to further enhance the performance of the interference rejector. Iterative algorithms that use the decoding information to improve the interference estimate are proposed, based on time domain LMS filtering and frequency excision.