Narrowband Interference Mitigation in DS-UWB Systems

Interference suppression is important for ultra-wideband (UWB) systems to operate over spectrum occupied by pre-existing narrowband systems. In this letter, we first extend the code-aided interference suppression technique to a direct sequence (DS) UWB system which has been proposed for narrowband interference (NBI) suppression in direct sequence spread spectrum (DSSS) systems. Then, we introduce a new type of spreading sequence, which significantly improves the NBI suppression capability of the code-aided technique. We also discuss a preamble-aided synchronization scheme for utilizing the new type of spreading sequence.