研究一种具有马尔科夫调制服务时间的单服务台排队系统。顾客到达服从参数为λ的泊松过程,服务时间为连续时间马尔科夫链调制,若马尔科夫链处于状态i(i=1,2,...N),则服务时间服从参数为μi的负指数分布。为优化排队系统采用仿真无线通信中信道衰减导致的信道速率变化问题非常有意义。区别于以往的数值计算方法(如矩阵几何分析),提出了一种离散时间马尔科夫链模型来分析服务台状态的变化过程,导出一组闭合公式来计算排队系统的各性能指标。此外,还开发出一种递推过程来计算队列长度的任意阶矩。数值计算结果显示出近似分析具有良好的精确性。
A single server queue that operates in a random environment defined by a Markov process with N states is considered:when the random environment is in state i(i=1,2,..N),the arrival is a Poisson process with rateand the packet service time is exponentially distributed with mean.This model is applicable to the scenario of wireless communication where the wireless link randomly deteriorates due to channel fading.In contrast to the existing numerical method(e.g.,Matrix-Geometric technique),an approximate model is proposed for the server state process,and the closed-form equations are derived to solve the system performance specifications.A recursive method is developed to calculate the moments of queue length.Numerical examples show the accuracy of the approximate method.