业务质量约束下最大化收益的HFC频点带宽分配方法

HFC频点带宽的分配是广播电视网络业务提供系统的一项关键技术,直接决定了系统的整体收益.描述了HFC频点带宽资源分配面临的问题,提出基于业务收益函数的频点带宽分配方法.在分析广电网络视频点播、时移电视和高速下载三种典型业务特性的基础上,给出了它们的收益函数,提出了一种基于边际效益的贪婪算法以完成资源的分配.该算法在保证业务质量满足最低要求的基础上,按照各类业务的实际需求分配可用的频点带宽,使系统的收益最大.仿真试验验证了该算法的有效性.     

多业务流量预测动态带宽分配方法

静态带宽资源分配方法或基于业务分类的动态带宽分配方法等很难适应业务流特性,无法保证各级业务的服务质量。设计了流量预测及带宽分配模型,给出了流量预测计算方法,提出多业务流量预测动态带宽分配方法（MSTPDBA）,该方法基于业务预测流量的大小进行可用带宽的重新分配。仿真实验证明了MSTPDBA的有效性,能控制不同业务的时延,并提高了系统带宽资源的利用率。     

IEEE 802.11e协议HCCA机制下的QoS研究

分析了IEEE 802.11e协议HCCA信道接入机制下的简单带宽调度算法对多媒体业务的QoS支持情况,指出其不足并在其基础上进行了改进,提出了一种基于业务等级的带宽调度算法E-HCCA（Enhanced HCCA）。E-HCCA对不同优先等级业务的数据在带宽分配上采用不同的策略,在优先保证各个节点CBR业务的基础上,根据节点的VBR流量动态平均分配剩余带宽。相比较简单调度算法,E-HCCA算法更好地支持了多用户下的语音业务流和视频业务流,降低了分组时延,增加了系统吞吐率。     

无线Mesh网络中基于业务价值的组播带宽分配方案

高延迟及低效益是无线Mesh网络中开展流媒体业务面临的主要问题。为解决该问题,首先赋予组播业务价值,该值反映了业务的网络优先级及效益优先级,并提出一个基于组播价值优先级的组播带宽分配方案。该方案第一阶段实施基于价值优先级的不区分业务类型的静态分配,通过对高价值业务的优先调度,实现了组播价值最大化及带宽效益最大化。在拥塞时,实施第二阶段的基于业务带宽需求调整及抢占的动态分配,保证了低时延约束业务的服务质量。仿真与常见算法的比较表明,所提出的方案在保证业务网络服务质量的同时,能实现带宽效益最大化。     

弹性光数据中心网络中收益最大化的带宽分配算法

弹性光数据中心网络中的带宽分配需要兼顾云服务提供商收益和用户连接请求性能,对此提出收益最大化的带宽分配算法,其以子载波为基本单位将光纤带宽有效地分配给多个用户连接请求。首先,基于收益模型和虚拟子载波的概念建立带宽分配问题的整数线性规划模型;接着提出一种基于动态规划的带宽分配算法以及一种启发式的带宽分配算法,前者致力于获得最大的分配收益,后者则力求获得更好的时间效率;最后,通过仿真实验对所设计的带宽算法的性能进行验证。实验结果表明,相较于已有的弹性光数据中心网络中的带宽分配算法,设计的两种算法均能在带宽分配中获得更高的系统收益。     

多优先级业务流多通道并行传输

针对已有的多业务流多通道并行传输不支持业务流之间优先级的问题,将业务的优先级映射到多个通道,建立了具有优先级保证的多业务流多通道数据传输模型。基于排队论知识将模型抽象成多维Markov链,并使用两阶段的PH分布将多维Markov链近似成一维Markov链,采用矩阵分析方法对模型进行定量分析,推导出系统的平均队长和平均等待时间。通过数值分析与简单多业务流单通道、多优先级业务流单通道、简单多业务流多通道这三种传输模型进行了比较。结果表明,不管业务流达到率如何变化,多优先级业务流多通道并行传输模型中的高优先级数据包均能够获得较高的处理能力,说明了该模型能够支持多通道并行传输中业务流之间的优先控制。     

一种面向业务的动态带宽分配方法

在分析传统QoS业务模型以及传统动态带宽分配方法（DBA）的基础上,提出一种面向业务的动态带宽分配算法。该算法吸取了各种QoS业务模型及传统动态带宽分配方法的优点,充分考虑了不同业务服务质量对带宽分配要求的差别以及带宽资源的利用率,仿真结果表明这种方法更加有效。     

一种自相似流量模型的带宽估计新算法

针对现今网络业务流量的自相似特性,选取具备显著自相似特征的分形布朗运动流(FBM)为自相似流量模型,提出一种基于统计网络演算理论的带宽估计算法。该算法利用统计网络演算建模,根据时延与带宽的关系建立出自相似业务流量模型带宽需求的统计模型。通过仿真验证和数值分析,结果表明该算法比有效带宽算法更为优越,得到的带宽估计结果更紧,可以更好地提高带宽资源利用率。     

WLAN与EPON融合接入网上行带宽分配算法

为了提高带宽的利用率,提出一种WLAN与EPON融合接入网上行带宽分配算法。该算法将无线终端接入的业务分为不同的服务等级,以实现不同业务Qo S保证。首先,ONU-AP给各个无线终端STA分配带宽,采用IEEE 802.11E协议的简单调度算法给语音业务和一般数据业务分配带宽,利用视频流的平均速率估算视频业务的传输带宽。其次,光线路终端OLT给各个ONU-AP分配带宽,OLT根据语音业务速率和当前视频业务流量分别估算语音、视频业务在下一个轮询周期的带宽,并将剩余带宽在重负载终端中二次分配,最后给一般数据业务分配带宽。通过仿真实验,结果表明:与传统算法相比,该算法的网络时延和丢包率明显降低,实现了带宽资源的合理分配。     

网络化运动控制系统的动态带宽分配策略

针对网络化运动控制系统带宽限制和静态分配无法有效利用带宽资源的问题,提出了基于控制性能指标和当前网络状态的动态带宽分配策略.在保证各控制环最小可用带宽的前提下,根据定义的代价函数优化分配剩余带宽资源,实现带宽使用的最小化和系统性能的最大化.从算法实现的角度,按平衡状态、扰动状态和最大需求状态给出了3种典型的带宽分配方案,仿真结果证明了方案的有效性.     

Dynamic bandwidth allocation for 3G wireless systems—A fuzzy approach

3G Wireless systems are to support multiple classes of traffic with widely different characteristics and quality of service (QoS) requirements. A major challenge in this system is to guarantee the promised QoS for the admitted users, while maximizing the resource allocation through dynamic resource sharing. In the case of multimedia call, each of the services has its own distinct QoS requirements concerning probability of blocking (P_B), service access delay (SAD), and access delay variation (ADV). The 3G wireless system attempts to deliver the required QoS by allocating appropriate resources (e.g. bandwidth, buffers), and bandwidth allocation is a key in achieving this. Dynamic bandwidth allocation policies reported so far in the literature deal with audio source only. They do not consider QoS requirements. In this work, a fuzzy logic (FL)-based dynamic bandwidth allocation algorithm for multimedia services with multiple QoS (P_B, SAD, ADV, and the arrival rate) requirements are presented and analyzed. Here, each service can declare a range of acceptable QoS levels (e.g. high, medium, and low). As QoS demand varies, the proposed algorithm allocates the best possible bandwidth to each of the services. This maximizes the utilization and fair distribution of resources. The proposed allocation method is validated in a variety of scenarios. The results show that the required QoS can be obtained by appropriately tuning the fuzzy logic controller (FLC).     

A new approach to dynamic bandwidth allocation in Quality of Service networks: Performance and bounds

Efficient dynamic resource provisioning algorithms are necessary to the development and automation of Quality of Service (QoS) networks. The main goal of these algorithms is to offer services that satisfy the QoS requirements of individual users while guaranteeing at the same time an efficient utilization of network resources.In this paper we introduce a new service model that provides per-flow bandwidth guarantees, where users subscribe for a guaranteed rate; moreover, the network periodically individuates unused bandwidth and proposes short-term contracts where extra-bandwidth is allocated and guaranteed exclusively to users who can exploit it to transmit at a rate higher than their subscribed rate.To implement this service model we propose a dynamic provisioning architecture for intra-domain Quality of Service networks. We develop a set of dynamic on-line bandwidth allocation algorithms that take explicitly into account traffic statistics and users’ utility functions to increase users’ benefit and network revenue.Further, we propose a mathematical formulation of the extra-bandwidth allocation problem that maximizes network revenue. The solution of this model allows to obtain an upper bound on the performance achievable by any on-line bandwidth allocation algorithm.We demonstrate through simulation in realistic network scenarios that the proposed dynamic allocation algorithms are superior to static provisioning in providing resource allocation both in terms of total accepted load and network revenue, and they approach, in several network scenarios, the ideal performance provided by the mathematical model.     

Achieving optimal revenues in dynamically priced network services with QoS guarantees

We have previously proposed the use of dynamically priced network services to provide QoS guarantees within a network. End-to-end QoS can be achieved by concatenating several of these services, perhaps from different ISPs. In this paper we consider the problem of a single ISP determining the bandwidth to allocate to each service, and on which path, in order to maximize revenue while guaranteeing end-to-end QoS. No knowledge of demand functions is assumed. Optimal allocation of bandwidth to services is first considered, where services are assumed to be routed on predetermined paths. We define the Iterative Allocation Adjustment heuristic, based on the concepts of tatonnement, which, through simulation, is shown to achieve over 95% of the optimal revenue for an ISP. We also examine how to value the links in the network to identify rerouting possibilities, or possible routes for new services, in order to improve the revenue of an ISP.     

基于移动Agent的无线多媒体传感器网络QoS路由算法

无线多媒体传感器网络(WMSNs)的主要特点包括资源有限、时延敏感和数据冗余性高。此外,音视频数据流传输所需的带宽是多媒体传感器节点所能承受的最大传输带宽的几倍。上述因素使得WMSNs的QoS 路由成为一个亟待解决的关键技术问题。鉴于此,首先通过基于等差数列的非均匀分簇算法对网络区域进行划分,然后在此网络拓扑上,提出一种基于移动Agent的WMSNs的QoS路由算法(MAQR)。MAQR由路由发现和数据传输两个阶段组成。在路由发现阶段,采用移动代理技术完成多路径路由发现。在数据传输阶段,采用多优先级多路径传输模型把数据流进行分类,并利用流量预测算法实现网络的负载均衡。最后,在NS-2平台上实现了MAQR,通过与同类算法进行仿真比较,发现MAQR较之同类算法能够明显地提高音视频传输的服务质量。此外,MAQR算法比同类算法的能耗更低。     

Analysis of bandwidth allocation on end-to-end QoS networks under budget control

This paper considers the problem of bandwidth allocation on communication networks with multiple classes of traffic, where bandwidth is determined under the budget constraint. Due to the limited budget, there is a risk that the network service providers can not assert a 100% guaranteed availability for the stochastic traffic demand at all times. We derive the blocking probabilities of connections as a function of bandwidth, traffic demand and the available number of virtual paths based on the Erlang loss formula for all service classes. A revenue/profit function is studied through the monotonicity and convexity of the blocking probability and expected path occupancy. We present the optimality conditions and develop a solution algorithm for optimal bandwidth of revenue management schemes. The sensitivity analysis and three economic elasticity notions are also proposed to investigate the marginal revenue for a given traffic class by changing bandwidth, traffic demand and the number of virtual paths, respectively. By analysis of those monotone and convex properties, it significantly facilitates the operational process in the efficient design and provision of a core network under the budget constraint.     

A Scalable Pricing Model for Bandwidth Allocation

In this paper, we present a scalable pricing model for dynamic bandwidth allocation. Using simulation we demonstrate that service providers can achieve increased revenue as well as better resource utilization without compromising user specified levels of Quality of Service (QoS). Our model allows for increasing the revenue while maintaining an acceptable level of QoS, this is done by selecting an appropriate bandwidth allocation policy, to reduce the number of blocked users.     

WiMAX拓展实时轮询调度机制分析

为了提高无线资源的利用率,使WiMAX系统更好地支持语音业务,基于IEEE 802.16e协议的QoS调度体系,提出了针对带有静默压缩语音业务的拓展实时轮询调度机制的具体实现方案.而且通过对方案中关键参数的分析,给出了一种QoS保证方法.方法根据用户时延对数据带宽分配进行补偿,并按照用户负载情况动态地调整轮询请求带宽的分配周期.使用OPNET软件进行了系统级性能评估,结果表明所提出的方法可有效地降低用户上行接入时延和上行丢包率,从而提高了通信质量.