Ayele, Hailu (PhD)Zeleke, Getu2018-06-282023-11-282018-06-282023-11-282007-10http://etd.aau.edu.et/handle/12345678/4346The demand for CDMA –WLL, Wireless Local Loop, Communication system is higher than wired network. The CDMA–WLL system in Addis Ababa is providing voice and data communication services. Because of its fast and reliable service, many customers are looking forward to be connected to the system. As CDMA’s nature, each CDMA –WLL user generates interference on the other users (Self jamming). The increasing number of users is going to cause system capacity limitation, unsatisfactory and degraded service quality , QoS. Addis Ababa CDMA-WLL system has started service provision with about 31,000 voice and 960 data communication users. As indicated above when the number of users increases, the service quality started degradation by dropping and blocking calls from the system with limited capacity allocation. These problems are results of improper planning and implementation work so that the system needs more technical solutions to provide better service quality, QoS and higher system capacity. To reduce the effect of the mentioned system problems, this thesis explores different techniques and methodologies. Cell sectoring and power controlling techniques pointed as the main performance enhancement methods3. . Using Power control as the main solution, WLL system’s major problems would be enhanced both in service quality and capacity. This thesis proposes efficient power control technique based on centralized SIR balancing algorithm. Performance characteristics, enhanced service quality and system capacity of the proposed technique are presented. The study also explains related advantages of signal to interference, SIR, based power control algorithm which are used to increase network capacity, extend battery life and improve quality of serviceenCommunicationThesis