Abstract
Ultra Wide-Band (UWB) communications is an emerging technology which can provide numerous advantages compared to conventional wireless systems. UWB technology aims to incorporate low-power, noise-like signal transmissions, making them ideal for use in Wireless Body Area Network (WBAN) communication systems. Towards this end, the work presented in this thesis is oriented to the statistical characterization and modelling of UWB-WB AN channels. The most important aspects of the work undertaken in this thesis are reviewed below. The first contribution of this thesis is an enhancement upon the existing UWB on-body channels. More specifically, an advanced Markov-chain technique has been employed in order to predict the path arrival sequence on channels of this sort. Results suggest that this methodology can accurately represent the experimental data, and provide more reliable results when compared to the classic Poisson approach. The second contribution of the thesis introduces a novel two-dimensional signal strength prediction model, applicable to the UWB off-body propagation channel, This model is based on real-body measurements, carried out in controlled environments. The parameters that characterize this specific propagation environment have been evaluated and validated by means of comparison with the empirical data. The third contribution of this thesis incorporates a generalization of the UWB off-body total power gain model for different types of indoor environments. More specifically, the effect of the indoor scattering in the received signal strength is thoroughly examined with respect to both the distance and body orientation. Furthermore, the small-scale fading, the temporal correlation and the time dispersion characteristics of the received signal are investigated. Finally, bringing all pieces together, a statistical Power Delay Profile (PDP) model for the evaluation and design of UWB off-body systems has been developed. Due to the dependence of the radio propagation channel on the body orientation, separate stochastic tapped-delay-line models are developed for each body region. It is shown that die proposed modeling technique can adequately capture the key channel metrics of the UWB off-body propagation channel.