Measurements, modeling and simulations of the UWB propagation channel based on direct-sequence channel sounding
The paper presents the statistical model for the ultra-wideband (UWB) indoor channel having a bandwidth of 2.4 GHz and a central frequency of 4.78 GHz. The model is based on propagation experiments performed in different rooms on a floor of an office-laboratory building. Within each room the receiver antenna is automatically moved over a square grid of 25 x 25 locations spaced 2cm apart. A correlative channel sounding technique is employed; actually the carrier is modulated by a train of short duration (0.4 ns) pulses shaped by a PN-sequence. After coherently demodulating the detected signals and removing the PN-sequence modulation, we post-process the extracted channel impulse responses by best-fit procedures to set up a statistical tapped delay line model (STDL) of the UWB indoor channel. We characterize the path loss for line-of-sight (LOS) and non-line-of-sight (NLOS) conditions by distance-power laws and the shadowing by lognormal distributions. A clustered structure is observed in the average power-delay profiles; rays arrive at the receiver in groups, exponentially decaying with different decay constants. The small-scale effects are modeled by the Gamma distribution since it verifies with a 95%-confidence interval both the Chi-Square test and the Kolmogorov-Smirnov test applied to the experimental data.. The shape parameters of such Gamma distributions are truncated Gaussian variables spreading in the range from 1 to 3. An implementation of the derived STDL model is finally proposed and a comparison between the simulated and the measured statistics is performed proving the validity of our approach. Copyright (c) 2005 John Wiley & Sons, Ltd.
statistical channel model uwb channel simulation uwb propagation measurements