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1、北京邮电大学硕士学位论文异构无线网络垂直切换机制的性能分析姓名：靳淑娴申请学位级别：硕士专业：计算机科学与技术指导教师：王文东20080228异构无线网络垂直切换机制的性能分析摘要随着多种无线接入网技术的出现与发展，以及用户全球移动性 和服务连续性要求的出现，使得不同接入网之间的融合成为了无线 网络的发展趋势垂直切换机制是一种处理用户在异构网络之间进 行切换的机制，它已得到广泛研究和应用，其目的就是保证用户在 不同网络之中无缝漫游WCDMA是一种成熟的3G技术。很多专家已经对WLAN与WCDMA 之间的垂直切换性能进行了研究TD-SCDIVIA是由我国提出的一种新 型3G技术，此技术已经在全球
2、范围引起关注，成为了研究热点对TDSCDMAWLAN异构网络垂直切换机制的性能分析是论文的 重点，并将其与WCDMA和WLAN之间的垂直切换进行比较用来评估垂直切换性能的参数有很多，例如抖动，延迟，容量，用户掉线率和用户阻塞率等论文以用户掉线率和用户阻塞率这两个参数来对 比这两种异构网络无缝漫游能力，并通过MATLAB平台对系统进行模 拟论文首先对WCDMA，TD-SCDMA和WLAN技术进行了简介，并介绍 了MATLAB平台的特点然后论文对这三个网络的接入控制机制进行了详细的描述。此机制的主要作用是检测网络中是否有足够的资源来满足新用户的要求，从而计算出异构网络的用户掉线率和用户阻 塞率论文
3、选用典型应用来对异构网络进行模拟和性能分析但由于 现实中网络的复杂性，论文简化了模拟场景：模拟区域是某一3G小区 内的边长为1000米的正方形区域：这个模拟区域内有两个WLAN； WLAN的覆盖范围是半径为100米的圆：网络中所有的用户都在缓慢 移动(步行)通过对已有无线网络模拟实验的分析，论文还介绍了网络模拟 中需要考虑的一些子模型以及这些子模型的实现这些子模型包括： 切换模型，流量模型和运动模型。其中切换模型用来决定切换在什么 时候开始进行初始化：流量模型用来模拟各个服务在网络中的流量行为：运动模型用来模拟网络中各个结点的运动方式，此模型直接 影响网络的容量以及其连接性基于以上的子模型，论
4、文对WCDMAWLAN和TDSCDMAWLAN这两 种垂直切换机制进行了模拟，并对其性能进行了对比和分析。论文最后对全文进行了总结，分析了研究中的不足并指出了今 后研究工作的方向关键词：TD-SCDMA WLAN WCDMA垂直切换接入控制PERFOR【ANCE ANALYSIS 0F VElUICALHANDOVER FOR HETEROGENOUS WIRELESS NETWORKWith the appearance and development of various wireless access technologies，the users increasingly demand
5、the global mobility and service continuity,SO the trend for the wireless network is to combine different access networks into a single oneTo guarantee the seamless roam capability of heterogeneous network，the vertical handover mechanism has been used widelyWCDMA has been used widely as a mature 3G t
6、echnology,and many experts has done a lot of research in the vertical handover between。AN and WCDM八Nowadays，a new 3G technology,1DSCDMA,proposed by China appears，nlis new technology has drawn the attention all over the world and becomes the focus of most researchTh【is thesis researches mainly in the
7、 mechanism of vertical handover between WLAN and TDSCDMA,which is compared with the handover between WLAN and WCDMAThere are many criteria usedto estimate the performance of handover：jitter,delay,capacity， call-dropping probabili哆and call-blocking probabilityIn this thesis， only the calldropping pro
8、bability and callblocking probability are taken into account to present the seamless roaming capability betweendifferent networks in the two systems，and the simulation is donethrough the platfom of MAn。ABFirstly,this thesisintroducesthe technology background of忙DMA,TD-SCDMA and WEAN,and it decribes
9、the characteristics of M衄AB tooThen the admission control mechanisms of the threeIIInetworks will be introduced in detail，and this mechanism is used to check that whether there is enough network resource to satisfy the new users requirementThen the calldropping probability and callblockingprobabilit
10、y of heterogeneous networks can be worked outThis thesis brings some typical kinds of traffiiC into the heterogenous network to analyze the performance of vertical handover Because of the complexity of the realistic network，this thesis simplizes the simulation scenario：The simulation area is a squar
11、e of1000m水1000m within a eell of 3G network：there are two WLANsexisting in the simulation area；theANs covering area is a circlewith the radius of 100 meters；the users in the heterogeneous networksare all supposed to be pedestriansThrough the study of former simulation of wireless network，this report
12、 also introduces the essential submodels with their implementationThese submodels include handover model，traffic model and mobility modelThe handover model is used to decide when the handover should be initialized；the traffic model is used to simulatethe related traffic behavior in the network：mobil
13、ity model is used tosimulate the mobility characteristies of every node in the networkBased on the submodels mentioned before，this thesis simulates the two vertical handovers of，CDMA、LAN andTDSCDM删AN repectively which are compared with each otherhere tooIn the end，this thesis sums up all of the cont
14、ent and describes the deficiency of the research as well as the future workKEY WORDS：TD-SCDMA,WLAN，WCDMA,vertical handovef，call admission controlIV图表目录图41 3G-twWLAN切换初始化删。 20图4-2 VILAN-to3G切换初始化【H(瑚I图43 WLAN，WCDMA和TDSCDMA中的传输模型 图44距离模型25 图4-5 RWP模型的Z字型运动【sND001图4-6RWP模型流程图。 28图47数据流量模型【删 29图4-8 ONOFF模型【J枷删图49离散马尔
