UWB wireless channels - propagation aspects and interplay with system design

This paper will first present an overview of the current state of the art in the measurement and modeling of UWB propagation channels. We will point out the difference between the two main frequency bands of interest (<900MHz and 3.1-10.6 GHz), and describe the kay channel parameters (attenuation, delay spread, arrival time statistics, amplitude statistics) in different environments. We will especially discuss the difference between "sparse" and "dense" models. We then analyze what channel parameters have the biggest influence on system performance. Various Rake receiver structures, OFDM cyclic prefix duration, and transmitted-reference structures exemplify the systems that show a clear dependence on channel parameters.