الفهرس 
Evolution of Mobile Communication SystemsOnly 14 pages are availabe for public view
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Abstract
Concentric ring shaped cells were used for a HAP system. The linear one dimensional vertical array was used. Different window functions were investigated for beamforming of the array. Particle Swarm Optimization was used for minimizing the sidelobes level. The effect of the different window functions and the optimization technique was introduced in measurements of the signal to interference ratio. The different HAP mobility models were investigated. A study of the Handoff probability, blocking probability, and dropping probability was introduced. The conclusions of this thesis can be summarized as follows:- Dividing the coverage area into concentric ring shaped cells is provided by one dimensional vertical linear array. PSO can control the sidelobes level better than the conventional window functions, e.g. Hamming and Dolph-Chebyshev. PSO shows an improvement in signal to interference ratio and coverage performance. The concentric ring shaped cellular configuration shows a good performance in the presence of different HAP mobility models. Results show a great reduction in the need of the mechanical stabilization where acceptable levels of dropping probability and blocking probability can be achieved.