Narrowband interference mitigation in an ultra-wideband receiver

Ultra-wideband (UWB) links are inherently subject to interference from other narrowband communication links. The paper proposes a solution for suppressing these narrowband interference sources that is based on using an analogue filter bank (AFB) for preprocessing the received signal. The AFB outputs are subsequently processed by a combination of maximum ratio combining (MRC) and generalised matched filter (GMF) processing. This receiver architecture requires significantly less processing than the optimum GMF processing while achieving a comparable performance in the context of narrow band interference (NBI). Furthermore, because the AFB consists of low-order bandpass filters of modest selectivity, monolithic integration is practical. Hence, the AFB is potentially a low-cost manufacturable implementation of the UWB receiver. Analysis and simulated performance of the AFB architecture are presented in this paper. The metrics used are the overall theoretical capacity and signal-to-noise ratio of the receiver decision variable. These results are presented as a function of the overall receiver complexity for different compositions of narrow and wide bandwidth channel noise. It is also shown that AFB forms a signal space of dimension equal to the number of bandpass filters and that the processing can effectively cancel multiple tones up to this dimensionality.