Modeling and Simulation of Initial and Handoff Accesses in a Mobile Computing Environment

• Main Authors: Luke Yi-Ren Wang, 汪以仁
• Other Authors: Chien-Chao Tseng
• Format: Others
• Language: en_US
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/91025670703939700176

碩士 === 國立交通大學 === 資訊工程研究所 === 83 === The communication infrastructure of a mobile computing environment can be built on the basis of a cellular/ microcellular telephone system or a PCS network. Under this circumstance, the occurences of handoffs cannot be avoided. With the occurences of handoffs, wireless links held by mobile computers crossing cell boundaries may be forced terminated. The forced termination probability of handoff access requests has a significant effect on the performance of a mobile computing environment. Moreover, the blocking probability of initial access requests is also an important metric of performance measurement. Several researches have been done on the analysis of the initial and handoff accesses in cellular/ microcellular telephone systems and PCS networks. However, the analytical models used in these researches are not appropriate for mobile computing since each telephone uses only one channel but a mobile computer may use several channels. In this thesis, we develop an analytical model to analyze the initial and handoff accesses in a mobile computing environment. This model is constructed with a multi-dimensional continuous time Markov chain. The accuracy of this model is verified by simulation. Besides, we also develop another simulation model to examine the effects of frequent disconnections. The simulation results show that increasing the probability that a wireless link will be disconnected may seriously degrade the performance of a mobile computing system. Furthermore, we provide an approach to balance the initial access blocking probability and the task incompletion probability.