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为了得到多服务台队列中流失率的高负荷极限,通过对有顾客流失的G/G/1/K队列进行推广得到G/GI/m/K队列,在高负荷条件下,获得了有m个服务台的队列系统中队长过程、流失过程的极限定理与流失比例的高负荷极限。以M/M/m/K队列为例,用Matlab编程进行模拟仿真,验证了理论结果的合理性,这是分析多服务台队列系统的一种新方法。 相似文献
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通过对于标准的多服务台队列M/M/n模型的负荷过程的高负荷极限的证明来解释鞅定理,该系统为泊松到达,指数服务。通过对所考虑的负荷过程进行流体刻画,并且使用鞅方法来证明多服务台队列M/M/n模型的负荷过程的高负荷极限,并得到所考虑的负荷过程收敛的结论。在高负荷条件下使用Matlab编程对此过程进行仿真模拟,模拟仿真以产生随机数的方式来进行计算,为今后排队论中证明随机过程(比如等待时间,流失过程,放弃过程等)的收敛提供了新的方法。 相似文献
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该文研究AAL2分组话音复接器缓冲器队列容量的确定方法,提出并从理论上证明用话音分组的最大排队时延为9ms作为确定缓冲器队列容量的标准,可很好地满足分组话音业务服务质量要求的结论。并推导出缓冲器队列容量及门限值的计算公式,仿真结果表明,按作者提出的方法确定缓冲器队列容量及门限值,可获得较低的分组丢弃概率和较小的平均分组排队时延;在满足分组话音业务服务质量要求的前提下,减少了话音分组缓冲器队列的容量,是一种很好的确定缓冲器队列容量和门限值的方法。 相似文献
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基于AOS的Hurst-优先级自适应RED与动态调度算法 总被引:1,自引:0,他引:1
为有效传输空间数据系统中多类型、大容量、突发性的数据,基于高级在轨系统(AOS)虚拟信道复用技术,提出了一种自相似参数Hurst-优先级自适应的随机早检测(RED)与动态调度算法——HPRED-DS。该算法在队列管理中设计了基于Hurst参数与优先级的2级丢弃分组策略,在虚拟信道调度中设计了VIP/同步/异步混合的动态调度模式,并将队列管理与虚拟信道调度有效结合起来。实验结果表明该算法在保持高处理效率和吞吐率的基础上,稳定了队列长度,降低了排队延时和延时抖动,并能满足AOS中不同业务的传输要求。 相似文献
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主动队列管理通过网络中间节点有控制的分组丢弃实现了较低的排队延时和较高的有效吞吐量,是TCP端到端拥塞控制近来研究的一个技术热点.已有的大多数算法在判定分组丢弃时大都沿袭了RED的概率丢弃机制,具有一定计算复杂度的随机数生成过程不利于路由器性能的优化.在本文中,我们首先定义了拥塞指数这一新的测度变量来量化描述网络的拥塞状态.接着,利用模糊逻辑设计了一种新的智能分组丢弃机制,离线的合成推理使得分组丢弃的判定仅需要简单的查表操作和比较运算即可完成,为优化路由器的性能提供了便利.数字仿真的结果表明:智能分组丢弃机制的性能优于经典的RED算法,控制队列的能力强,鲁棒性好,稳定工作域大,能很好地抵抗突发性和非弹性业务的干扰,适合工作在瞬息万变的动态网络环境中. 相似文献
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段金友 《信息技术与信息化》2014,(6):146-147
有限的资源和随机的需求是排队论存在的基础,而在如今的社会,这种现象越发广泛和复杂。我们将要求服务的顾客和提供服务的机构组合成一个系统,称之为排队系统。这种系统存在于各个方面,本文研究的是排队论运用在通信网络中的各端业务问题。排队论系统分为优先制排队系统和非优先制排队系统,本文描述了带有非强占权优先制的排队系统,其模型为两队中其中一对带有优先制度的M/M/1的模型。根据此模型可以定义变量,画出状态转移图并列出状态方程,最后求出稳态解。通过性能分析发现,带有优先权的M/M/1模型系统与一般模型相比性能将会有所提高,这也是优先制度的体现。 相似文献
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We present an exact decomposition algorithm for the analysis of Markov chains with a GI/G/1-type repetitive structure. Such processes exhibit both M/G/1-type & GI/M/1-type patterns, and cannot be solved using existing techniques. Markov chains with a GI/G/1 pattern result when modeling open systems which accept jobs from multiple exogenous sources, and are subject to failures & repairs; a single failure can empty the system of jobs, while a single batch arrival can add many jobs to the system. Our method provides exact computation of the stationary probabilities, which can then be used to obtain performance measures such as the average queue length or any of its higher moments, as well as the probability of the system being in various failure states, thus performability measures. We formulate the conditions under which our approach is applicable, and illustrate it via the performability analysis of a parallel computer system. 相似文献
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In a Jackson-type queuing network with feedback, the equilibrium state distribution of each queue is that of anM/M/s system. In support of a previous conjecture that nevertheless the input processes in such a network are not Poisson, the marginal interarrival-time distribution for an equilibriumM/M/1 queuing system with feedback, counting both fed-back and exogenous customers as arrivals, is calculated. Since this distribution is a mixture of two exponentials, the total input to such a system is not Poisson. 相似文献
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Mohsin Iftikhar Hassan Mathkour Muhammad Imran Abdullah Bedaiwi Athanasios V. Vasilakos 《Wireless Networks》2016,22(4):1269-1284
Provisioning guaranteed Quality of Service (QoS) in multiservice wireless internet is challenging due to diverse nature of end-user traffic (e.g., voice, streaming video, interactive gaming) passing through heterogeneous interconnected domains with their own policies and procedures. Numerous studies have shown that multimedia traffic carried in wireless internet possesses self-similar and long-range dependent characteristics. Nonetheless, published work on wireless traffic modeling is merely based on traditional Poisson traffic distribution which fails to capture these characteristics and hence yield misleading results. Moreover, existing work related to self-similar traffic modeling is primarily based on conventional queuing and scheduling combinations which are simple approximations.This paper presents a novel analytical framework for G/M/1 queuing system based on realistic internet traffic distribution to provide guaranteed QoS. We analyze the behavior of multiple classes of self-similar traffic based on newly proposed scheduling-cum-polling mechanism (i.e., combination of priority scheduling and limited service polling model). We formulate the Markov chain for G/M/1 queuing system and present closed form expressions for different QoS parameters i.e., packet delay, packet loss rate, bandwidth, jitter and queue length. We develop a customized discrete event simulator to validate the performance of the proposed analytical framework. The proposed framework can help in building comprehensive service level agreements for heterogeneous wireless domains. 相似文献
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The M/G/1 queue with permanent customers 总被引:2,自引:0,他引:2
The authors examine an M/G/1 FCFS (first come, first served) queue with two types of customers: ordinary customers, who arrive according to a Poisson process, and permanent customers, who immediately return to the end of the queue after having received a service. The influence of the permanent customers on queue length and sojourn times of the Poisson customers is studied using results from queuing theory and from the theory of branching processes. In particular, it is shown that, when the service time distributions of the Poisson customers and all K permanent customers are negative exponential with identical means, the queue length and sojourn time distributions of the Poisson customers are the (K +1)-fold convolution of those for the case without permanent customers 相似文献
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I. V. Strelkovskaya T. I. Grygoryeva I. N. Solovskaya 《Radioelectronics and Communications Systems》2018,61(3):128-134
The work considers a queuing system of the G/M/1 type that simulates service of self-similar traffic in a NodeB (e-NodeB) base station of a mobile operator. The feature of quality of service (QoS) characteristics estimation process for the self-similar traffic defined by the Weibull distribution is the solution based on the Laplace–Stieltjes transformation. The Laplace transformation for an infinite number of items under the Weibull distribution condition was found. It was shown that this series was equiconvergent to some convergence domain. The following QoS characteristics were obtained for the self-similar traffic: the average amount of time that a request spends in the system; the average number of requests waiting in the queue and the average queue length. The obtained results allowed to consider the real values of traffic serviced by a NodeB (e-NodeB) for their optimal deployment over a covered territory at the stage of frequency planning and operation of the 3G/UMTS and 4G/LTE networks. 相似文献
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《AEUE-International Journal of Electronics and Communications》2014,68(5):429-436
This paper presents a new queuing model for performance analysis of go-back-N automatic repeat request (GBN-ARQ) protocol in cooperative wireless networks. In the model, cooperative medium access control (CoopMAC) protocol and dynamic radio link adaptation are taken into consideration. We analyze the probability distribution of the total delay witnessed by packets at the source side. Multi-rate transmissions are considered for all links with link adaptation. An enhanced Markov model is introduced in our model, which encompasses the following aspects: CoopMAC protocol at the MAC sub-layer; GBN-ARQ protocol at the logical link control sub-layer and the transmission using decode-and-forward cooperative diversity at the physical layer. The stochastic process of random feedback delay because of peers contending for a common helper is analyzed. The queuing system is modeled as a GI/M/1 Markov chain to acquire statistics of the exact queue length and the total delay. We analyze the effects of Doppler frequency shift and packet arrival rate on the total delay. The analysis is validated by simulation. 相似文献
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In this letter, we investigate the queue behavior with Pareto interarrival and exponential service time distribution. By numerical analysis and simulations, we analyze the asymptotic and the exact loss probabilities of GI/M/1/K to show the big discrepancy between the asymptotic and the actual loss probability and propose a model for the loss probability of Pareto/M/1/K as a function of the buffer size K and the geometric parameter. 相似文献