标题: UMTS差别性服务等候机制效能应用二种伫列空间配置之研究
A Study on Performance Discussion of a UMTS Priority-based Queuing Scheme with two Queuing Buffer Allocations
作者: 刘芳萍
Liu, Fan-Pyn
杨 千
Yang, Chyan
资讯管理研究所
关键字: 服务等级;优先伫列机制;逻辑伫列缓冲记忆体溢位;动态伫列缓冲记忆体配置;差异性服务;连续性加权轮询伫列机制;UMTS;priority-based queuing scheme;DQB allocation;OQB allocation;differentiated service packet forwarding;sequential weighted round robin queuing scheme
公开日期: 2009
摘要: 自美国、日本和欧洲各国提出第三代无线通讯系统协定标准,如TD-SCDMA、CDMA2000与WCDMA / UMTS以来,较广为业界所看好的技术规格为WCDMA / UMTS,因为目前使用人口最多的GSM欧洲系统业者也加入参与制定,且GSM是世界上最大的第二代移动通信网路,UMTS势必成为第三代行动通讯主流规格。3GPP所提出UMTS 的3G标准,可以确保GSM核心网路无缝 (Seamless) 接取到3G的核心网路,这种相容于过去GSM / GPRS系统的考量,对于系统业者不仅可投资延续价值,也兼顾商业上的经济效益。
3G R5以后的规格及4G网路已朝向全IP化的方向发展,并以IP作为主要通讯协定,因此,UMTS的语音会话、影音串流、网页互动及档案传输的四种资料类型,都有其特定的属性质,并赋予不同的封包传输顺序,以达到符合各类型资料的服务等级 (Quality of Service, QoS) 的要求及目标,由于IP协定中的尽力而为服务(Best Effort Service),对于严格要求低延迟、低抖动(Jitter)等服务的多媒体类或语音的资料型态,已无法满足需求,因此,提供优化的封包转送能力(Packet Forwarding)以达到服务等级要求,成为UMTS核心网路中一项重要的工作。
本论文提出的方法是在UMTS系统核心网路中,对不同的资料类型,提供差异性服务及优先顺序的封包传送能力,利用两种伫列缓冲记忆体空间配置机制:动态伫列缓冲空间配置(DQB)和逻辑伫列溢流缓冲空间配置(OQB),另外,对各类型封包允入与允出伫列时的机制,分别以优先顺序为基础方式(Priority-Based Queuing)允入伫列及连续性加权轮询(Sequential-Weighted Round Robin)的允出伫列机制处理。透过NS2网路模拟软体,对不同方案想定、封包大小及参数值进行模拟评估,根据模拟的结果,每一种类型服务的封包在效能(Throughput)、封包丢失率(drop probability)、延迟及抖动率与IETF所提出之差异性服务(Differentiated Service, DiffServ)比较,两者可达到近似的效能。
As UMTS systems will evolve into an all-IP stage in the future, packet switching becomes a prerequisite for all UMTS applications. The 3GPP defines four types of UMTS traffic: conversational, streaming, interactive and background; each type of UMTS traffic has its QoS features. Differentiated Service (DiffServ) is QoS architecture for IP networks, their based on packet marking that allows packets to be prioritized according to Service Level Agreement (SLA) management. The DiffServ is a scalable architecture and is proposed to provide QoS guarantee services and scheduling packets forwarding for each class within the IP networks.
According to four types of UMTS traffic, this study proposes a priority-based queuing scheme with two queuing buffer allocations, the dynamic queuing buffer (DQB) allocation and the overflow queuing buffer (OQB) allocation, to support packet forwarding of four types of UMTS traffic in a DiffServ method. In the proposed queuing scheme, two major modules, a priority-based enqueuing module and a sequential weighted round robin (SWRR) dequeuing module, base on the DQB allocation and the OQB allocation to perform differentiated packet enqueuing / dequeuing jobs among four types of UMTS traffic.
In this study, we use the ns2 (Network Simulator version 2) as the simulation platform to simulate several scenarios. Discussing the simulation results and analysis, we can find the proposed queuing scheme can base on packet transmission priorities of four types of UMTS traffic to support a differentiated packet forwarding behavior among UMTS traffic in a UMTS core network and the performance of UMTS traffic with a high priority always gets a better packet forwarding performance than that of UMTS traffic with a low priority. And, the differentiated packet forwarding behaviors with the proposed queueing scheme are similar to the packet forwarding behavior with the IETF DiffServ scheme.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT079034808
http://hdl.handle.net/11536/40270
显示于类别:Thesis


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