Intra-vehicle UWB channel characterization and receiver design.

摘要

One objective of this research is to characterize Ultra-wideband (UWB) propagation within commercial vehicles and obtain the knowledge of UWB channels in intra-vehicle environments. Channel measurement is performed in time domain for two environments and different multi-path models are used to describe the two different propagation channels. In one environment, the transmitting and the receiving antennas are inside the engine compartment. It is observed that paths arrive in clusters and the classical Saleh-Valenzuela (S-V) model can be used to describe the multi-path propagation. In another environment, both antennas are located beneath the chassis. Clustering phenomenon does not exist in this case and the power delay profile (PDP) in this environment does not start with a sharp maximum but has a rising edge. A modified stochastic tapped delay line model is used to account for this rising edge. Furthermore, for this environment, data are collected for a vehicle in both stationary and moving scenarios. Statistical analysis shows that car movement does not significantly affect the characteristics of UWB channel beneath the chassis.;Clustering phenomenon exists for the Ultra-Wideband (UWB) propagation in many environments. To manually identify clusters in the UWB impulse responses is very difficult and time consuming when a large amount of data needs to be processed. Furthermore, visual inspection highly depends on the person who performs the cluster identification task, which may lead to inconsistent and unrepeatable results. In this dissertation, an automatic procedure to identify clusters in UWB impulse responses is proposed.;Another objective of this research focuses on the design and performance analysis of digital transmitted reference (TR) UWB receivers with slightly frequency shifted (SFS) reference. Motivated by the flexibility of digital system and the availability of sophisticated digital signal processing circuits, this dissertation proposes a digital implementation of the SFS receiver with low quantization resolution. Performance analysis of such a digital receiver is done based on both the measured channel data from the intra-vehicle UWB environments and the channel impulse responses generated by indoor and outdoor channel models available in literature.