| المستخلص: |
Simulcast transmission, is widely used by private and public access mobile radio systems to provide wide coverage area. In simulcast transmission, the service area is covered by several base stations with overlap areas between them. All base stations operate on the same radio frequency and simultaneously broadcast the same information. A mobile roaming in overlap area may receive two signals or more with different amplitudes, phases and times of arrival. Accordingly, a severe multipath environment is introduced. This limits the maximum data rate that can be transmitted over the channel. Therefore, studying and modeling the simulcast channel is important to design and implement such systems. One of the most important parameters to study and model such channel is the rms delay spread. It is defined as the second central moment of the power delay profile. Estimating this parameter can help to determine the width of the overlap area such that no equalization is required. The statistical properties of the rms delay spread in two- path mobile radio environment have been investigated considering Rayleigh, lognormal, Rician and Nakagami fading channels. However, the Weibull distribution fits data more than other distributions. It introduced an excellent fit to fading channel measurements for indoor as well as outdoor environments. In this thesis, the statistical properties of the rms delay spread in two path mobile radio environment are investigated. A simple simulcast transmission system consists of two base stations with overlap area is considered. Each path is assumed to have a weibull distribution with exponential decay power delay profile. A closed form equations for the probability density function (PDF), the cumulative density function (CDF), the mean, the mean square and the standard deviation of the local rms delay spread are derived. An extensive Monte Carlo simulation is also generated to validate the analytical model.
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