Study on Performance Analysis of Multimedia Traffic and Access Methods in Mobile Communication Systems

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In this study :(1) We first evaluated the performance of Bluetooth. Next, we evaluated the characteristics of both WLAN and Bluetooth systems that are operating at short range. This means the basic service areas overlap with each other. Significant performance degradation was observed when operating both WLAN and Bluetooth systems simultaneously.(2) We presented a new realistic multi-layer cell architecture for distributed control, in which there could be one or more cell layer types. The cell size for each cell layer type was fixedly selected according to cell radius in the cellular structure. We also presented an efficient analysis to evaluate the performance of such mobile cellular wireless systems by using ARP method.(3) We suggested a new method using recursive search algorithm based on a 7 cells repetition. In this assignment method, it takes shorter time to find an optimal or a semi-optimal channel assignment than in other methods, which satisfies minimum adjacent interference. … More We also showed that the method is valid. We then applied the technique to several different channel assignment environments. We also presented the difficulties encountered in this method and further improvements.(4) We presented an analysis method for an integrated voice and data wireless LAN with non-persistent carrier sense multiple access with collision avoidance (CSMA/CA) protocol to exactly derive the moment generating function of the packet interdeparture time for the output process. Numerical examples included comparisons between the single and multiple traffic system models in term as the coefficient of variation of packet interdeparture time by differentiating the moment generating functions.(5) We investigated an optimal replacement problem of a system in a semi-Markov environment. A special case of Markov environment was discussed, and the state space could be simplified equivalently to be finite, so the real computation of the problem is feasible. Finally, a numerical example was given to prove the correctness and validity of the analysis.(6) We investigated the properties of the optimality equation and optimal policies in discrete time Markov decision processes with expected discounted total rewards under the weak conditions that the model is well defined and the optimality equation is true.(7) We considered two types of interference conditions for channel assignment : a co-channel interference within distance of two cells and a adjacent channel interference within the same and the adjacent cells. We presented our recursive search algorithm together with the neighborhood improvement structure. Then we minimized or disallowed these two types of interference in order to achieve optimal channel assignment. Less