Asymmetric Threshold Service Polling System Model And Performance Analysis

Polling system as a vital sort of control model has got common application for the fairness and practicability of control mode in automatic industrial control, computer TDM, communication system protocol, computer network and military industry field so on. However, the original analysis and research mostly concentrated on the symmetric polling system and if having a deeper understanding of polling system we need the study change from the originally single service strategy to mixed service strategy and from the symmetric problem to asymmetric one. Only in this way, the control of polling system will become more flexible and effective and can become more powerful utility in the application of more fields.The accurate resolution of gated, exhaustive and limited(K=1) service polling system is theoretical and applied fundamental of the polling system for the time and is the starting point of researching asymmetric polling system. The paper, after building mathematical model of the system and defining system parameters and working condition, using the embedded Markov chain and probability generating function as a mathematical tools, accurately analyzes basic polling system and deduces 1-order and 2-order characteristics and cycle period, furthermore, accurately calculates average queue length and average waiting delay. By simulation experiments and theoretical calculations the paper discussed the relationship among characteristics of basic polling system. Meanwhile, the paper expatiated on polling system evolution, underlying the study of asymmetric polling system.In terms of periodical inquiry service system packet number, packet length and packer servicing-time such parameters are random variables. Therefore, analysis of the related performance is considerably complex. Especially for the study of asymmetric system, because of problems of the analysis the results were obtained in a certain limit of local conditions. After establishing mathematical model and defining system parameters and working conditions, the paper accurately analyzed discrete-time, double queue asymmetric gated service polling system by the means of embedded Markov chain and probability generating function as mathematical tools, and deduced 1-order and 2-order characteristics. Moreover, the paper accurately calculated average queue length and average waiting delay of information packet. Simulations and theoretical calculation have good consistency. The research laid the foundation for study of the multi-queue asymmetric gated service polling system and had positive implications for the more flexible control of polling system.In the asymmetric polling system, due to the interaction among the terminals and the complexity of probability distribution of the random variables in the system accurate resolution to the multi-queue asymmetric polling system appears more difficult. Study on asymmetric polling system is mainly to find optimal approximate analytical method. After establishing mathematical model and defining system parameters and working conditions, by the means of embedded Markov chain and probability generating function as mathematical tools, the paper accurately analyzed discrete-time, multi-queue asymmetric gated service polling system and deduced 1-order characteristics. The paper accurately calculated average queue length and cycle period of information packet. And the paper deduced 2-order characteristics and average waiting delay of information packet by reasonable approximation. Simulations and theoretical calculation have good consistency. Simulation experiments draw the conclusion that waiting time ratio in service period of each terminal approximately obeys a certain proportion when the load is not heavy. This research further deepened cognition to asymmetric gated service system and have a positive significance to expand the research extent of polling system.The paper consists of five chapters:The first is the introduction for expatiating on the conception, research method of polling system and main task of the paper. The second is the foundation of the paper. And it introduced a new accurate resolution to the symmetric polling system. It accurately analyzed the symmetric polling system with three different services strategies-gated, exhaustive and limited, by the means of embedded Markov chain and probability generation function and compared their performance. The third is the creative part of the paper and the emphasis. It established 2-queue asymmetric gated polling system model. By the means of embedded Markov chain and probability generation function it accurately analyzed 1-order and 2-order characteristics, average waiting queue length and average waiting delay. S Simulations and theoretical calculation have good consistency. The forth is another creative part of the paper and it is the hard and emphasis of the paper. It is the emphasis and difficulty part of the paper. It established queues asymmetric gated polling system model. By the means of embedded Markov chain and probability generation function it accurately analyzed 1-order characteristics and average waiting queue length. By the reasonable approximation it better resolved 2-order characteristics and average waiting length of the asymmetric gated polling system. Simulations and theoretical calculation have good consistency. The fifth is the summarization of the paper. And it narrated the study problem and gained academic achievements. At last it proposed the expanded aspect and some problems to be resolved badly..