Measurements, modeling and simulations of the UWB propagation channel based on direct‐sequence channel sounding

Abstract

AbstractThe 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 × 25 locations spaced 2 cm 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 © 2005 John Wiley & Sons, Ltd.