Data-aided nonlinear filter for narrowband interference rejection in DS-SS systems: closed-form analytical results

The performance of the data-aided nonlinear filter (DNF), for combating narrowband interference (NBI) in direct sequence spread spectrum (DS-SS) systems, is analyzed. Closed-form analytical expressions for improvement in signal to interference-plus-noise ratio (SINR) are derived under the condition of single tone interference. Results show that the DNF structure outperforms conventional nonlinear prediction filter.