Partial-code-aided scheme for narrowband interference suppression in direct-sequence spread spectrum systems

The non-linear filtering is a commonly used time-domain technique for narrowband interference (NBI) suppression in the direct-sequence spread spectrum (DSSS) communication systems. In this study, the authors analyse how the decision feedback error of the spread spectrum (SS) signal influences the performance of the NBI prediction. A partial-code-aided scheme is proposed, which despreads partial chips in a spreading sequence and reconstructs the rest part by spreading the bit decision. This method utilises partial spreading gain to improve the decision accuracy of the SS signals while keeping similar time consumption and implementation complexity with the traditional scheme. It has been verified by simulation that with different NBI models and under different channel conditions, the proposed non-linear filtering method always outperforms the traditional one with chip-wise decision feedback.