【作者】 宋志刚；

【导师】 朱刚；

【作者基本信息】 北京交通大学 ， 通信与信息系统， 2009， 硕士

【摘要】 采用第三代移动通信技术的优势在于,网络运营商可以依赖于更高的频带利用率和更高的传输速率,为用户提供丰富的业务。随着移动通信网络与互联网(Internet)之间的业务交互在通信中的比例日益增加,如何在IP网络与UMTS(Universal Mobile Telecommunication System,通用移动通信系统)之间提供有效的业务质量(QoS,Quality of Service)保障已经成为当前端到端业务质量保障研究的重点。本文首先对IP网络的QoS保障机制进行研究,主要对IETF(InternetEngineering Task Force,互联网工程任务组)提出的集成业务模型和区分业务模型进行了研究,并对两种QoS模型的相关保障机制进行了比较分析。同时,本文对UMTS网络的QoS体系进行了深入研究,重点分析了UMTS网络的流量等级划分和QoS协商过程,并对采用IP机制的核心网功能进行了探讨。在对IP网络的两种QoS模型进行比较的基础上,本文选取区分业务模型作为UMTS核心网承载业务的实现方案。在区分业务模型的架构下,对核心网分组域关键网元的QoS机制进行了设计。同时,对其中流量控制模块中的拥塞控制和队列调度方案进行了研究和比较,提出了采用随机早期检测丢弃策略和加权公平排队调度策略的流量控制功能模块,以期对QoS性能进行改进。另外,本文根据UMTS固有的流量等级和UMTS交互类业务特有的业务处理优先级,将UMTS流量等级与区分业务模型的行为聚类进行了映射。同时,将UMTS各流量等级所共有的分配保留优先级和区分业务模型中确保转发每跳行为的分组丢弃等级相结合,对交互类业务进行了两级划分,进而制定了UMTS流量等级与IP网络每跳行为的一一映射关系,保证了QoS机制的实现具有互操作性。最后,本文采用仿真软件对上述设计方案进行了分析和验证。从仿真的结果可以看出,采用区分业务模型的UMTS核心网与未采用区分业务模型时相比,对分组应用的QoS保障性能在时延、抖动和丢包率方面都有明显的改善。更多还原

【Abstract】 The advantage of the Third Generation of mobile system(3G) is that the network providers could make full use of the edge-cutting technologies to provide a wide range of applications for subscribers.With the interaction between mobile network and the Internet grows constantly at a high speed,how to provide an efficient Quality of Service(QoS) guarantee scheme between IP(Internet Protocol) network and UMTS (Universal Mobile Telecommunication System) has already become a focus in the field of end-to-end QoS.This paper firstly presents the QoS schemes in the IP network,mainly the Integrated Services(IntServ) and the Differentiated Services(DiffServ) proposed by IETF(Internet Engineering Task Force),and does the comparison between them. Meanwhile,the QoS architecture of UMTS is also analyzed in this paper,especially the QoS management functionality,the traffic classes and the QoS negotiation process in it. Based on the comparison of the two kinds of IP QoS provision scheme,DiffServ is chosen to be the one for the Core Network(CN) in UMTS.Here the functions of the SGSN(Serving GPRS support Node) and GGSN(Gateway GPRS support Node) are defined,which are the essential elements in CN.Furthermore,the congestion control and scheduling schemes are the objects of the research,and Random Early Detection and Weighted Fair Queuing are the appropriate combination scheme in the nodes of UMTS CN after cautious comparison.In the framework of the classification system in UMTS,the combination of the Allocation/Retention Priority and the Traffic Handling Priority that is the distinct characteristic of the Interactive Class,divides the Interactive Class into several sub-classes,which could be used to mapped with the variety of AF PHBs(Assured Forwarding Per-Hop Behavior) in DiffServ model,in conjunction with the Streaming Class.At the end of this paper,a model is constructed in the simulation software to evaluate the performance of the proposed QoS management scheme of UMTS CN backbone bearer service.It is concluded that the scheme proposed in this paper is an efficient one for CN bearer service,which could improve the performance of packet handling in delay,jitter and loss ratio.更多还原