A Statistical Multi-Cluster Indoor Channel Model in an Office Environment for Ultra-Wideband Signals
Thiagarajah, Sharlene (2005) A Statistical Multi-Cluster Indoor Channel Model in an Office Environment for Ultra-Wideband Signals. PhD thesis, Universiti Putra Malaysia.
This thesis presents a new statistical multi-cluster indoor channel model for ultrawideband (UWB) communications between 0.1 to 2 GHz. The proposed model has been developed based on 924 measured channel impulse responses conducted at 24 different locations over a single floor in a typical modem office environment. The multi-cluster channel characteristics are modeled according to 10 independent channel parameters extracted from the large-scale and small-scale statistical analysis of the received energy delay profiles (EDP). Three new channel parameters were introduced to better describe the time and energy dispersion statistics of the UWB signal. They are the maximum excess delay (MED), decay factor, y within the MED and energy gains variations between adjacent bins, X. The pulse propagation characteristics were further modeled according to several path topogaphies. In addition, two new path loss prediction models were developed to take into account the attenuation factor (AF) due to gypsum and brick wall, the two main obstructing walls in this experiment. The proposed multi-cluster channel model improves the prediction accuracy of the UWB pulse characteristics for various path topographies due to its detailed parameterization of the channel statistics. In comparison, the channel model of Cassioli et a]. in 2001 was developed using only three independent lognormal parameters, i.e. shadowing, o, decay factor, y and the energy gains ratio, r. Furthermore, Cassioli et al. proposed a single cluster channel model without topographical classification. The channel model of Alvarez et al. in 2003 however was developed based on five channel parameters extracted from analysis conducted in the frequency domain. This method does not accurately capture the time delay statistics of the transmitted pulse. The experimental results indicate the U WB signal's high immunity against fades and its attractiveness for propagation in tunnels. In addition the UWB channel was observed to exhibits a wide-sense-stationary-uncorrelated-scattering (WSSUS) characteristic which simplifies the transfer function between the time and frequency domains via a single Fourier transform.
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