الفهرس 
?IntroductionOnly 14 pages are availabe for public view
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Abstract
Long Term Evolution (LTE) is a new broadband technology, which promises to provide a reliable multimedia telecommunication link between a base station and a mobile station. Its broadband capability qualifies it to be used in a lot of applications. LTE can be considered as the beginning of the fourth generation mobile system. The coverage area of the LTE may have dead zones, where there is no coverage or a weak coverage. These dead zones include zones inside tunnels, or indoor zones. The lack of network coverage at these zones results in a poor service for the users, who are inside these zones. These dead zones represent a defect in the LTE system. Femtocells are small and low emitted power base stations, which can cover a small range. They can be deployed indoor to optimize the system coverage at these zones. Unfortunately, the femtocells may share the spectrum with the existing LTE macrocells, which results in a mutual electromagnetic interference among them. Moreover, an interference may occur among the femtocells themselves due to utilizing the same frequencies. The interference among the macrocells and the femtocells can be reduced by reducing the emitted power of the femto base stations according to one of the power control algorithms.
In this thesis, a cognitive radio is introduced as a proposed tool to mitigate the interference among the macrocells and the femtocells. Simulation results show that, applying the cognitive radio is a better solution than power control algorithms. Moreover, the LTE cognitive femtocells system is designed and mathematically analyzed. Applying the cognitive radio can mitigate the interference among the macrocells and the femtocells.