一种新的对称CDMA系统中非对称业务下的呼叫允许控制策略

未来无线多媒体网络将以分组技术为基础,支持多种业务的传输,业务的QoS保证将受到一定的挑战.各运营商也将针对自己所服务的对象特点,定义各类业务的QoS等级,来提供具有不同QoS要求的业务.因此,呼叫允许控制(Call Admission Control,CAC)策略将要以分组业务为主要对象,即既要在充分利用系统资源的基础上保证各业务的QoS要求,又要适应各运营商之间的不同需求.因此本文提出一种新的对称CDMA系统中非对称业务下基于动态QoS保证的CAC策略.各运营商可根据自己的要求定义各业务的QoS等级.由于业务的不同特性,使得网络中上行链路和下行链路的业务呈现不对称性,为避免资源的浪费,将根据网络中的资源占有情况动态的地分配上行和下行链路中的资源.仿真结果表明,该策略可以自适应地保证各业务的QoS要求,提高了业务间的公平性和系统资源的利用率.     

支持多优先级QoS的业务量疏导算法

针对当前业务量疏导研究中很少涉及的QoS约束的问题,提出并研究了一种支持多优先级QoS的业务量疏导算法（Differentiated Traffic Grooming Algorithm,DTGA）,该算法综合考虑了对不同等级业务QoS和网络资源利用率的优化。与目前实用的WDM光网络业务量疏导算法的性能仿真对比表明,DTGA能有效地降低高服务等级需求业务的阻塞率和节省网络资源。     

LTE中应用于业务保障的QoS技术研究

本文描述了3GPP R8 QoS概念,包括EPS QoS架构、EPS QoS关键参数及实现机制.通过PCRF为各用户的各类业务流制定对应的能够保证业务服务质量的QoS策略.应用于业务保障,并可使具有较高等级的用户优先享用带宽、功率等资源.     

基于多门限预留机制的自适应带宽分配算法

针对异构无线网络融合环境提出了一种基于多门限预留机制的自适应带宽分配算法,从而为多业务提供QoS保证。该算法采用多宿主传输机制,通过预设各个网络中不同业务的带宽分配门限,并基于各个网络中不同业务和用户的带宽分配矩阵,根据业务k支持的传输速率等级需求和网络状态的变化,将自适应带宽分配问题转化为一个动态优化问题并采用迭代方法来求解,在得到各个网络中不同业务和用户优化的带宽分配矩阵的同时,在带宽预留门限和网络容量的约束条件下实现网络实时吞吐量的最大化,以提高整个异构网络带宽的利用效率。数值仿真结果显示,所提算法能够支持满足QoS需求的传输速率等级,减小了新用户接入异构网络的阻塞概率,提高了平均用户接入率并将网络吞吐量最大提高40%。     

WiMax终端上行调度算法的研究与设计

在对WiMax终端的不同业务类型调度算法进行分析的基础上,提出了一种有效的上行调度算法实现策略.与传统的基于严格优先级的调度算法相比,本算法在保证各业务QoS参数的基础上,提高了不同业务之间的公平性,使优先级较低的业务也可以获得相应的调度机会.     

支持多优先级QoS的业务量疏导算法

文章针对当前波分复用(WDM)光网络中业务量疏导技术研究的局限性,提出支持多优先级服务质量(QoS)的业务量疏导算法--MTGA.该算法基于业务流QoS的需求,将业务标记为不同等级,然后尽量选择占用跳数最少的通路来建立连接.仿真结果显示,与已有算法相比,MTGA能够有效地降低有时延约束连接请求的阻塞率.     

一种新的基于GPON的动态带宽分配算法

为了实现吉比特无源光网络(GPON)带宽分配的公平性,降低网络的丢包率及传输延时,文章研究了GPON系统传输汇聚层的帧结构及动态带宽分配的实现方法,提出了一种新的动态带宽分配(DBA)算法--基于QoS的二层动态带宽分配算法.基本思路是根据不同等级业务的带宽需求,在PON层和ONU层分别进行带宽的合理分配.理论分析和仿真试验证明,这种算法可以提高带宽的利用率,保证不同业务的不同时延要求,并且对不同用户和不同等级的业务都具有很好的公平性.     

光网络中一种考虑信号损伤限制和服务质量区分的动态RWA算法

在光网络中,光信号沿着路由与波长分配(RWA)算法选定的光通路传输的过程中会受到各种信号损伤的影响而导致信号质量的不断下降,严重影响着业务的服务质量(QoS).而光网络中多样化的客户层业务往往有着不同的QoS的需求,因此有必要根据不同的业务QoS需求对光信号损伤的影响进行不同程度的控制.针对这一问题,提出了一种能同时考虑信号损伤限制和服务质量区分的动态RWA算法,并通过计算机仿真的方法对其性能进行了分析和验证.结果表明:该算法既能克服光网络中信号损伤的影响又能为不同级别的业务提供不同的QoS保证,更贴近实际需求.     

OFDMA系统中基于多目标优化的无线资源分配算法

本文提出了OFDMA系统中基于多目标优化的无线资源分配算法.针对不同业务的QoS要求,建立多目标优化模型,并提出一种多业务分级分配算法通过确定优先级、引入合适的参数获得次优解.仿真结果表明,该算法不但能够保证不同业务的QoS要求,而且能够兼顾相同业务的用户之间的公平性.     

UMTS核心网中基于区分服务的QoS控制模型

3G新业务的发展，要求UMTS提供端到端QoS控制。文章构建了在UMTS核心网中为不同业务类提供QoS保证的区分服务模型，提出了从UMTS业务类到DiffServ域服务等级的映射方案，设计了一种新的队列调度算法，采用优先级和分离机制，在流量调整器配合下可满足不同业务类的QoS要求。最后，通过模拟实验证明了模型的有效性。     

浅析QoS中的令牌桶算法

对QoS领域中的令牌桶算法进行了研究,首先对端到端QoS技术的实现方式进行了阐述,然后介绍了流量整形中的令牌桶算法,并且对单速双桶和双速双桶令牌桶算法进行阐述和分析。最后对MQC平台实现令牌桶算法进行分析。在LTE时代,由于大带宽需求、业务低时延要求的新型业务不断出现,基于流量整形的令牌桶算法应用可以应对上述问题而成为QoS研究的新热点。     

Cross‐layer and cognitive QoS management system for next‐generation networking

Owing to limited wireless network resources, network applications must provide an adaptive quality‐guaranteed service to satisfy user requirements. Different applications are associated with different quality of service (QoS) concerns, as well as different QoS control parameters. This work presents an adaptive QoS algorithm by discussing the QoS specifications of three wireless access technologies, i.e. 3G, WiMAX and WiFi. Based on cross‐layer and cognition concepts, these environmental parameters are integrated with the sensing of spectral and received signal strength from a cognitive radio paradigm. An adaptive QoS algorithm is then proposed to select the optimal access network for services. Simulation results indicate that the proposed adaptive QoS algorithm outperforms available ones in real‐time applications. Compared with traditional algorithms, the proposed algorithm reduces not only the average delay time and jitter for VoIP services to 0.16 s and 0.09 ms, respectively, but also the packet loss ratio for high‐definition video streaming by 3.4%. Copyright © 2011 John Wiley & Sons, Ltd.     

Improved MLWDF scheduler for LTE downlink transmission

In long-term evolution (LTE) downlink transmission, modified least weighted delay first (MLWDF) scheduler is a quality of service (QoS) aware scheduling scheme for real-time (RT) services. Nevertheless, MLWDF performs below optimal among the trade-off between strict delay and loss restraints of RT and non-RT traffic flows, respectively. This is further worsened with the implementation of hybrid automatic retransmission request (HARQ). As these restraints grow unabated with increasing number of user demands, the performance of MLWDF further reduces. In order to ameliorate this situation, there is a need to directly incorporate the variations in user demands and HARQ implementation as parameters to the MLWDF scheduler. In this work, an improvement to the MLWDF scheduler is proposed. The improvement entails adding two novel parameters that characterise user demand and HARQ implementation. The scheduler was tested using varying three classes of service in QoS class identifiers (QCIs) table standardised by Third Generation Partnership Project for LTE network to characterise different services. It was also tested on the basis of packet prioritisation. The proposed scheduler was simulated with LTE-SIM simulator and compared with the MLWDF and proportional fairness schedulers. In terms of delay, throughput and packet loss ratio; the proposed scheduler increased overall system performance.     

Multimedia quality transmission evaluation over wireless networks: a survey

In recent years, usage of multimedia applications has increased dramatically, especially after the evolution of 3G and 4G technologies. Moreover, the development of new user devices, such as laptops, Smartphone, etc. increased very steeply and rapidly, to support different types of services and different means of communication satisfying user’s needs. Here, the challenge is how to make those services available to users with a high quality; we speak here about quality of service (QoS) and quality of experience. In this survey, we examine different characteristics of wireless networks to determine the enhancements introduced by each technology. Particularly, we focus on the benefits and limitations of three main technologies which are WiMAX, UMTS and LTE, and the role of each one in increasing QoS satisfaction for multimedia application. A comparison is also done between researches already published in Multimedia quality evaluation over wireless networks topic, taking into account some considerations, such QoS parameters, used simulator, assessed applications, etc. All those help us to extract the strengths and limitations of those researches.     

基于QoS保证的多用户OFDM系统跨层资源分配

针对正交频分复用(OFDM)系统资源分配和调度问题,提出一种基于第三代移动通信长期演进(LTE)系统的分块跨层资源分配算法。此算法考虑物理层的信道状态信息、媒体接入层(MAC)的有限用户缓存队列长度、用户的丢失率和时延等QoS要求,以提高系统频谱效率为总体目标。通过从实时视频业务和混合业务两种业务类型下进行大量对比分析,得出提出的算法能有效提高系统的频谱效率和降低系统时延。     

一种基于CoMP的随机接入方案

提出了一种新的基于协作多点传输和接收（CoMP）技术的多发随机接入流程,并根据 随机接入的目的和业务类型设计了接入优先级,在此基础上设计了一种新的随机接入方案, 对 不同类型的随机接入请求提供不同的接入机制,以保证边缘用户的接入性能和满足不同业务 的QoS需求。仿真结果表明,与LTE标准随机接入方案相比,该方案对系统整体接入性能略有 提高,且大大提高了边缘高优先级用户的接入性能。     

Quality of Service Drivers in LTE and LTE-A Networks

In the last years, cellular operators have experienced a rapid growth of mobile broadband subscribers and traffic volume per subscriber. At the same time, operators are moving from a single to a multi-service offering by adding new services such as multimedia telephony and mobile-TV. In this challenging scenario, the Quality of Service (QoS) concept provides network and service operators with a set of tools to enable service and subscriber differentiation. This paper presents an overview of the QoS drivers in Long-Term Evolution (LTE) and LTE-Advanced (LTE-A) networks, focusing on their QoS policy control capabilities. Proposals of policy control and management for increasing the QoS in LTE and LTE-A networks are described. This paper also includes a detailed list and analysis of the inputs to the Policy and Charging Rules Function (PCRF) that can be used for policy decision as well as a set of use cases involving the Policy and Charging Control architecture: (1) the analysis of a potential cooperation between the PCRF and a Deep Packet Inspector, and (2) the analysis of a potential interaction between the PCRF and the radio scheduler to provide a consistent end-to-end QoS.     

移动互联网业务在LTE时代的发展分析及业务建模

LTE时代的到来为移动互联网业务的发展提供了新的平台,也给运营商带来巨大的挑战。文章探讨了移动互联网业务在LTE时代的发展趋势,并且针对不同类型业务的业务特征进行分析和理论建模。通过对LTE网络的业务构成、用户行为、业务特征等方面的研究,构建LTE业务总体模型,为LTE网络部署提供有效支撑。     

Cost models for QoS-differentiated interconnecting and wholesale access services in?future generation networks

Currently, network operators and Internet service providers are offering ??Triple Play?? products integrating services with different Quality of Service (QoS) requirements. It is leading to Internet traffic with strong service integration under an all-IP-based broadband network platform. However, new multimedia service offers require individual QoS guarantees for each type of services. The interconnection between different providers necessitates the reconsideration of the actual cost schemes. Interconnection and wholesale access services (It is an extension of ??wholesale network?? definition, where Telco??s physical network and equipment are ??shared?? to many independent Service Providers. If the incumbent offers broadband access services, the rest of the alternative providers have recourse to the incumbent??s ??wholesale access service??. Bitstream service is the most important service of this type, actually regulated over DSL and cable networks.) appear to be a simple solution, but the consideration of QoS parameters requires an extension of the current network dimensioning methods based mainly on the average bandwidth demand from each user. This paper proposes a cost model which considers QoS parameters and, based on the ??Total Element based Long Run Incremental Cost?? (TELRIC) model, is applied to the wholesale access and interconnection paradigm. Three traffic engineering methods are considered and studied for network dimensioning. Hereby the aim is to guarantee the QoS of the different services: complete traffic segregation under virtual tunnels, complete traffic integration by over-engineering and partial traffic integration using a priority queuing scheme. The proposed method enables the development of a specific cost scheme based on a complete scenario considering different types of users. The variety of used IP applications suppose direct implications over different levels of interconnection, mainly at the low-level Metro access and the high-level edge node.     

软件定义卫星光网络蚁群优化波长路由技术

针对卫星光网络中网络拓扑动态时变和业务类型多样化的问题,研究了在软件定义网络架构下保障服务质量的路由技术,提出了一种基于多业务的卫星光网络蚁群优化波长路由算法。通过改进蚁群算法的启发函数,将波长空闲率、时延、时延抖动、丢包率作为蚂蚁选路的重要依据,为业务选择了满足多种服务质量的最优路径;采用分组波长分配方法对不同等级的业务进行了区分服务,为不同业务分配了不同的波长集。仿真结果表明:与CL-ACRWA算法和Dijkstra算法相比,降低了卫星光网络的平均时延、平均时延抖动、平均丢包率,提高了波长利用率,同时也降低了高优先级业务的网络拥塞概率。