Download or read book Performances des syst mes de communication Ultra large bande impulsions radio written by Jocelyn Fiorina and published by . This book was released on 2005 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time Hopping Impulse Radio Ultra Wide Band (TH-IR-UWB) systems are the object of the studies in this thesis. We first introduce the UWB principles and then propose new signalling schemes together with a synthetic comparison of the performances of different modulation possibilities.A key point in UWB performances is the Multi User Interference (MUI). In the first studies on UWB, MUI was supposed to be Gaussian. We see in our thesis that this hypothesis is not always true and that it overestimates UWB performances. By developing an impulse collision model, we propose a formula allowing a better estimation of the bit error rate. We also reveal a stochastic resonance phenomenon showing the unusual aspect of UWB interferences.Then we perform a detailed analysis of MUI, which allows us to work out the condition of Gaussianity and non-Gaussianity of the interfering signals. This results help in understanding MUI and, thanks to it, we may demonstrate the existence of a trade-off between the repetition factor and the frame length.Finally we propose a simple receiver adapted to the UWB MUI, which performances are greatly increased and may in some cases outperform the prevision of the Gaussian approximation which was considered to be too optimist before.