Wideband Power Modeling and Time Dispersion Analysis for UWB Indoor Off-Body Communications

A statistical model for ultrawideband (UWB) off-body communication channels is proposed. The presented results are the outcome of extensive real-body measurements carried out in the frequency range between 3.5 and 6.5 GHz in typical indoor environments. The signal power gain is modeled by a log-linear dual-breakpoint model, the parameters of which depend on both the body orientation as well as the distance between the transmitter and the on-body sensor. The general trend implies that in large distances, the received signal strength is less sensitive to changes in the body orientation angle, especially if propagation occurs in dense multipath environments. Furthermore, the small-scale channel variations of the total received signal strength are found to follow a normal distribution. This fact was verified by means of the central limit theorem (CLT), since correlation between multipath components is found to be negligible. Moreover, time dispersion analysis is provided by means of RMS delay spread. Finally, based on the newly estimated parameters, a model implementation for wideband power is proposed and several comparisons between the empirical data and the simulation results are presented.