【作者】 赵庆林；

【导师】 李忠诚；

【作者基本信息】 中国科学院研究生院（计算技术研究所） ， 计算机系统结构， 2005， 博士

【摘要】 随着IP技术和无线通信技术的发展和融合,互联网在向宽带发展的同时开始向无线移动方向发展。对于无线移动网络来说,发现移动终端的当前位置以及维持其当前通信连接是必须要解决的问题。移动IP正是解决这一问题的网络层方案,它已成为未来移动通信的基石。然而,移动IP并非完美无暇,例如,它可能引起显著的网络开销和冗长的切换延时等。在下一代无线移动网络中支持实时应用对移动IP的效率提出了挑战。这已经激发了人们极大的研究热情。当前从理论上分析移动IP性能的研究还很欠缺。本文首先把增强移动IP效率的最新技术划分成七类:基于物理位置的策略、基于本地运动的策略、基于IP搜索的策略、基于路由变化的策略、基于下层信息的策略、基于决策引擎的策略、基于服务转移的策略,分别进行了阐述。在此基础上,本文从移动检测、切换特征、区域登记三个方面对移动IP的性能进行了理论建模和分析,其创新工作如下:移动检测延时分析:本文首次采用更新过程理论研究了移动IP中两种基本的移动检测策略——热心蜂窝策略和懒汉蜂窝策略,得到了一般性的移动检测延时概率分布表达式。在此基础上,针对它们的缺点——检测延时长、参数配置困难等,提出了把移动检测与网络状况相结合的动态策略,并用复合泊松过程理论对提出的策略进行了建模和分析。数值结果显示:本文提出的策略能够减少不必要的检测延时,优于现行的移动检测策略。切换特征分析:本文首次根据蜂窝布局、切换类型、移动速度等因素对移动IP切换过程中的切换延时、丢失分组数目、乱序分组数目等进行了理论建模,得到了它们各自的概率分布公式。根据这个结果,对蜂窝重叠区域大小进行了优化。数值结果显示:提出的模型能够准确地刻画移动IP的切换特征。本部分的研究成果有助于评价移动IP的切换性能。区域登记分析:本文首次提出用驻留时间去捕获移动节点的区域运动特征——移动节点离开一个网关外部代理(GFA)域时经过i个外部代理(FA)域的概率,获得了这个概率的一般性结果。如果驻留时间服从爱尔兰分布,那么这个概率依赖于GFA域平均驻留时间与FA域平均驻留时间之比。使用这个概率,本文分析了移动IP区域登记策略的位置更新费用和分组转发费用,并优化了GFA域的大小。本部分的研究成果有助于对区域登记费用进行分析。更多还原

【Abstract】 As the Internet and wireless communication networks are growing and fusing fast, Internet is going toward bandwidth networks and wireless and mobile networks. As for wireless and mobile networks, one of the most important problems is to discover mobile node’s current location and maintain its all ongoing communications. In the next generation wireless and mobile networks, Mobile IP is a network layer solution to this problem and is playing a role of footstone. However, using Mobile IP may cause excessive signaling traffic, long signaling delay and so on. The real-time applications in the wireless and mobile networks have challenged these drawbacks which have inspired lots of research with great interest.The researches which numerically analyze the Mobile IP’s performance are deficient. This thesis firstly divides the recent technologies which enhance the efficiency of Mobile IP into seven types of schemes: physical location based scheme, localized mobility based scheme, IP paging based scheme, route change based scheme, lower layer based scheme, decision engine based scheme and service transfer based scheme, expounds them respectively. Then, from the theoretical viewpoint, the thesis models and analyzes the movement detection, handoff characteristic, regional registration. The innovations of the thesis are the followings:Movement Detection: For the first time, using the renewal process, two basic movement detection schemes——eager cell switching scheme and lazy cell switching scheme are analyzed and the general probability expressions about the movement detection delay are obtained. Then, focusing their drawbacks——long movement detection delay and difficult parameter configuration etc., the thesis proposes the dynamic schemes which combine the current network state, and numerically analyzes them by the compound Poisson process. The numerical results show that the proposed schemes outperform the existing ones, which can reduce the unnecessary increase in movement detection delay.Handoff Characteristics: For the first time, from the cellular network layout, handoff category and movement velocity etc., the thesis numerically analyzes the handoff characterizations of Mobile IP respectively: handoff delay, packet loss,更多还原