Communication Engineering

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Browsing Communication Engineering by Author "Abera, Tadele"

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    Frequency Assignment Problem Optimization of GSM Network in the case of Addis Ababa
    (Addis Ababa University, 2014-09) Abera, Tadele; Negash, Yalemzewud
    In GSM systems, radio frequencies are repeatedly used in order to efficiently use assigned frequency bands. To expand the network capacity, one solution is to reuse the limited frequency resources. Currently the 4x3 frequency reuse technologies for GSM network is in common use here in Addis Ababa. For this reuse model “4” indicates the number of Base Transceiver Stations (BTSs) in the reuse clusters, and “3” indicates the number of cells (sectors) under each BTS. As the number of users increases from time to time, the number of cells increases. Thus, the search space which is the possible range where optimum solution is attained increases. Furthermore, attaining optimum frequencies under each cell is challenging task. This thesis presents group frequency assignment method for the frequency assignment problem in Addis Ababa using genetic algorithm technique. Without violating the 4x3 frequency reuse used currently, the optimization was performed in Addis Ababa with 933 DCS (Digital Communication) 1800 MHz bandwidth cells (sectors). With proper optimization five frequencies can be used under each cell with a group of 24 cells and 125 generations or iterations using the algorithm. This assignment enhanced us to use two more frequencies under each cell than ethio telecom assignment which uses Mentum planet as optimization tool. And thus, capacity of the system increased. Key words: Frequency Assignment Problem Optimization; Genetic Algorithm