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Title: Spatio-temporal processing for indoor UWB array propagation channels
Author: Makaratat, Khajitpan
ISNI:       0000 0004 2681 1864
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 2009
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This thesis mainly focuses on the study of the spatio-temporal processing for indoor UWB array systems. The main objective of this work was to investigate the spatial and temporal characteristics of UWB signals captured by planar array and also linear array systems. These characteristics include space-time array processing and application based spatio-temporal results on UWB receiver systems. Firstly, simulation of UWB array systems based on multipath clusters and distortion effects is investigated. This modified simulation contains spatio-temporal characteristics of UWB arrays such as discrete channel impulse responses based on classifications of multipath clusters, propagation environments and physics-based pulse distortion effects. Frequency dependent characteristics are also analysed in the simulation. Thus, discrete impulse responses and distorted pulse signals are simulated in each frequency sub-band corresponding to particular channel parameters of directions of arrival, times of arrival and distortion effects. Furthermore, quantifications of distortion impact on UWB system are evaluated; UWB simulated data is measured corresponding to propagation scenarios in order to determine system performances. Secondly, analysis of the spatial correlation based array structure is presented. This novel spatial correlation technique is processed between surrounding adjacent antenna positions for each multipath component time bin. Therefore, variations of spatial correlations with excess delays can be temporally analysed. The contributions of this technique and preliminary results are also given as the application on estimation of times of arrival of multipath components. In addition, based on the spatial correlation analysis, the applications of angles of arrival estimation are also described in this thesis. To simplify this technique, the linear array configuration is exploited cooperatively with the relative phase difference method. UWB linear array measurements are also carried out in an anechoic chamber with the controlled conditions to evaluate estimated results. Additionally, the research also presents a complex spatial correlation analysis, which can be used as the identification of distortion effects at each individual time bin. Finally, UWB RAKE receiver systems are investigated in order to highlight the application of UWB space-time array processing, which is proposed as the adaptive multipath searching unit. The multipath searching and distortion selection processors are constructed to support RAKE selection and weight estimator functions. The implementation of this proposed structure associated with the finger selection strategies and the time-reversal mirror technique can improve UWB array link performances in dense channels with less complexity.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available