Performance analysis of a DS-UWB system in the presence of narrowband interference

Ultra-wideband (UWB) systems spread the transmitted signal power over an extremely large frequency band, and the power spectral density of the signal is very low. Due to the wide bandwidth of the transmitted signal, UWB signal energy spreads over the frequency bands allocated to other radio systems. Evaluating the interference issues of these narrowband systems to UWB systems in its overlay band is an important issue for understanding and designing efficient UWB systems. An analysis of the power spectral density (PSD) of generic narrowband signals is presented. The theoretical and simulation results reveal that the bit-error-rate (BER) performance of a direct sequence UWB (DS-UWB) system with a minimum mean square error (MMSE) receiver is robust in the presence of narrowband interference caused by existing applications.