A Statistical Analysis of Multipath Interference for Impulse Radio UWB Systems

TL;DR

This paper provides a statistical framework for analyzing multipath interference in Impulse Radio UWB systems, enabling better chip time tuning to mitigate interferences based on channel characteristics.

Contribution

It introduces analytical expressions for multipath component power distribution and interference probability, aiding adaptive system design in UWB communications.

Findings

Derived exact probability expressions for multipath cluster occurrence.

Developed a power delay profile approximation for interference power estimation.

Enabled rapid chip time adjustment to optimize SNR.

Abstract

In this paper, we develop a statistical characterization of the multipath interference in an Impulse Radio (IR)-UWB system, considering the standardized IEEE 802.15.4a channel model. In such systems, the chip length has to be carefully tuned as all the propagation paths located beyond this limit can cause interframe/intersymbol interferences (IFI/ISI). Our approach aims at computing the probability density function (PDF) of the power of all multipath components with delays larger than the chip time, so as to prevent such interferences. Exact analytical expressions are derived first for the probability that the chip length falls into a particular cluster of the multipath propagation model and for the statistics of the number of paths spread over several contiguous clusters. A power delay profile (PDP) approximation is then used to evaluate the total interference power as the problem appears to be mathematically intractable. Using the proposed closed-form expressions, and assuming minimal prior information on the channel state, a rapid update of the chip time value is enabled so as to control the signal to interference plus noise ratio.