Wideband and Ultrawideband Channel Models in Working Machine Environment

We present statistical models for wideband and ultrawideband (UWB) radio channelsin a working machine cabin environment. Based on a set of measurements, it was found that such a smalland confined space causes mostly diffuse multipath scattering rather than specular paths. The amplitudeof the channel impulse responses in the wideband case is mostly Rayleigh distributed small-scale fadingsignal, with only a few paths exhibiting Ricean distributions, whereas the ones in the UWB case tend tobe log-normally distributed. For the path amplitude, we suggest an exponential decay profile, which hasa constant slope in dB scale, with the corresponding parameters for the UWB case. For the widebandcase, a twofold exponential decay profile provides excellent fits to the measured data. It was also notedthat the root-mean-square (RMS) delay spread is independent of the line-of-sight/obstructed line-of-sightsituations of the channel. The multipath components contributing significant energy play a major rolein such a small environment if compared to the direct path. In addition, the radio channel gains areattenuated with the presence of a driver inside the cabin