Multiple narrowband interference suppression for UWB communication systems in Nakagami fading channels

Abstract

This paper investigates the performance of ultra-wideband (UWB) communication systems in the presence of multiple in-band narrowband interference signals in a Nakagami-m frequency selective fading channel. The UWB systems have a restraint on their transmission power levels in order to control its interference to other in-band operating services; however UWB systems unavoidably suffer from the interference caused by the coexisting systems such as the IEEE802.11a signal, making it extremely difficult to maintain adequate signal-to-noise-and interference ratio (SNIR) levels. In order to mitigate the impact of such strong interference the paper proposes a suppression technique which introduces spectral nulls at the operating frequencies of the narrowband interference (NBI) signals. The bit error rate performance of the proposed scheme is derived in a Nakagami multi-path frequency selective fading channel and validated with simulation. The results show that with the use of such proposed technique the NBI impact can be effectively suppressed leading to an improvement to the bit error rate performance of the UWB communication systems. A comparison with a notch filter-based case is also presented where it will be shown that the proposed technique out performs a perfectly tuned notch filter.