A novel approach for estimating multi-user interference in impulse radio UWB networks: The pulse collision model

Modeling Multi-User Interference (MUI) is crucial in the design of wireless networks. In the case of Impulse Radio (IR)-Ultra Wide Band (UWB) networks, most of the adopted models are inspired by the legacy of the reference literature on spread spectrum communications, and do not address specific features for IR systems, where spectrum spreading is basically obtained by the radiation of very short time-limited pulses. The problem of conceiving a specific model for MUI in IR-UWB networks is addressed in this paper. The reference scenario consists of multiple asynchronous users transmitting IR-UWB signals using Pulse Position Modulation (PPM) in combination with Time Hopping (TH) coding. We provide a novel analytical expression for the average BER based on the observation that interference in IR is provoked by collisions occurring between pulses belonging to different transmissions. The proposed method requires specification of a similar set of system parameters as Gaussian-based approaches, but shows improved accuracy in estimating BER.