On the narrowband interference in transmitted reference UWB receivers

In this paper, we study the performance of a transmitted reference (TR) system corrupted by a single tone interferer in a multipath noise-free channel. It is shown that the auto-correlation of the narrowband interferer, arising from the dirty template adopted in the signal demodulation, can be modelled as a bias term. The magnitude of this term depends on the frequency of the tone interferer, and it can enormously affect the receiver performance. However this kind of interference can be completely suppressed by designing a simple delay and chip code, without requiring any information on the frequency of the interferer. The cross-correlation between the UWB and the narrowband signals can be modelled as a random variable, for which we derive the analytical probability density function. The statistic of this term also depends on the carrier frequency of the tone interferer, and a method is proposed to mitigate its effects.