Frequency-selective fading of ultrawideband wireless channels in confined environments

As a result of the recent ruling by the European Commission, ultrawideband (UWB) wireless communications can now pervade small confined environments such as cars or trains. This research studies frequency-selective fading experienced by UWB wireless channels in these confined environments. It focuses on the relationship between the severity of fading and the environment size using analytical modelling, simulation and measurement. The authors show that the frequency-selective fading is more severe in smaller environments because the bandwidth required to resolve all multipaths in time is inversely proportional to the cubic root of the volume of the environment. They show that the European Computer Manufacturers Association (ECMA) International standards for UWB proposed by the WiMedia alliance may not provide sufficient means of mitigating the issues associated with the frequency-selective fading in confined environments such as cars.