Adaptive jammer suppression using decision feedback in a spread-spectrum receiver

The authors compare the performance of three least-mean-square (LMS) adaptive structures which supplement direct-sequence (DS) spread-spectrum techniques in the suppression of jammers. In addition to a single-input LMS adaptive structure without decision feedback, two LMS structures which use decision feedback are evaluated. Probability-of-error results are presented, and convergence properties are investigated. It is concluded that LMS adaptive filtering improves the probability-of-error performance of a DS spread-spectrum system operating in the presence of stationary single-tone jammers. It is also shown that when compared with the no feedback case, LMS adaptive systems with decision feedback do not degrade probability of error performance; however, decision feedback does not always appreciably improve system error rates.<
>