Equivalent system model of ISI in a frame-differential IR-UWB receiver

A discrete-time equivalent system model is derived for the intersymbol interference in a differential ultra wideband (UWB) impulse radio (IR) system operating in a multipath propagation environment. Data is transmitted using differential binary modulation on a frame-level (i.e., among UWB pulses), which is a variant of the well-known transmitted reference UWB schemes, proposed for higher data rates. It is shown that the UWB system is accurately modeled as a second-order discrete time Volterra system. Equations are presented to determine the coefficients of this non-linear model. The impact of noise is characterized. The proposed model can be used to develop signal processing algorithms for UWB-receivers in order to enhance the data rate or multiuser capabilities, for instance.