UWB indoor diffusion channel model and its application to receiver design

UnrestrictedMany design efforts in Ultra-wideband (UWB) communication need information about the channel power profile and delay spread. For example, power profile provides important information for UWB ranging, transmitted reference (TR) and square-law detector designs. In this study an analytic diffusion model for UWB indoor channel is proposed. The channel model was analytically derived based on diffusion phenomenon and a set of stochastic differential equations (SDE). It was hypothesized that the multiple wave reflections in the rich scatter indoor environment cause a diffusion-like energy behavior. The resulted Markov process has the statistics of a geometric Wiener (geometric Brownian motion) process. The approach considers the channel in continuous-timespace with fewer parameters compared to characterizing thediscrete multipath components.; Some applications of the proposed channel model in UWB signal filtering and receiver design were considered. The results on filter design show increased Signal-to-noise ratio (SNR) and signal to interference plus noise ratio (SINR) at the presence of narrow band interference (NBI) without any information about the interference. For applications with inexpensive receiver requirement (e.g., IEEE802.15.4a), a modified energy detector (ED) receiver was proposed.; A challenging task in UWB ED and TR receivers is to determine the optimum integration length. The analysis of channel delay spread based on the diffusion model was used to determine the optimum integration interval in TR and ED receivers for impulse radio UWB. It was shown that the optimum stopping time (in terms of effective SNR of the decision variable) which minimizes the bit error probability can be obtained in a computationally inexpensive algorithm without precise information about the channel model parameters. The method can be effectively implemented even with analog components. The optimization is conducted in real time, based on a particular realization of the channel. As such, the new method offers performance superior to schemes based on optimizing on averaged statistics. The optimality of the estimated stopping time is preserved even in the presence of some synchronization errors