【作者】 王青；

【导师】 孟洛明；

【作者基本信息】 北京邮电大学 ， 通信与信息系统， 2013， 硕士

【摘要】 随着无线通信技术的迅猛发展,异构无线接入网络之间的融合已成为未来无线通信发展的必然趋势。在异构无线网络融合环境下,如何充分发挥不同接入网各自的优势,在多种网络重叠覆盖的区域为移动终端提供无缝的业务连续性,是异构无线网络融合研究中的热点问题。3GPP标准化组织在系统架构演进(SAE)中引入了多接入PDN连通性及IP流移动性的方案,为异构无线网络之间的无缝切换提供了更细粒度的操作方式,同时也开启了异构无线网络融合的新纪元。IP流移动性是指对于集成多种网络接口(如3GPP,WiFi, WiMAX等)的移动终端来说,既能够通过3GPP接入系统接入到3GPP核心网,同时也能够通过非3GPP接入系统接入到3GPP核心网,来访问3GPP的分组数据网络业务,且能够实现业务数据流在异构接入网络之间的移动,即在一个接入上进行传输的某些业务数据流可以根据需求移动到另一个接入上进行传输,并保证业务的连续性。本文基于3GPP标准的研究成果,首先介绍了IP流移动性的基本概念、应用场景,阐述了支持IP流移动性的系统架构、解决方案以及信令流程。在对应接口上分别基于DSMIPv6和PMIPv6进行系统间移动性信令及协议的增强,为终端控制IP流移动性和网络控制IP流移动性提供了技术支持。由此,本文从终端触发／网络辅助和网络触发／终端辅助两个角度,对IP流移动性的具体实现进行了机制和算法的探索和研究。在基于终端触发的流移动性方面,针对接入网发现与选择功能(ANDSF)对于IP流移动性的支持,考虑到ANDSF在为移动终端提供流移动性相关的路由策略时会存在策略信息不准确、不及时等问题,本文对现有ANDSF机制进行了三方面的增强,包括由终端上报其可用接入网信息、在ANDSF中引入处理用户配置文件功能以及新增与HSS之间的接口,解决了机制中对于非3GPP接入网络的精确度不高而造成的冗余消息过大的弊端,为终端触发流移动性提供了更好的策略支持。在基于网络触发的流移动性方面,本文通过深入研究多属性判决算法,结合IP流移动性的特点和目的,提出了一种适用于网络侧触发流移动性的机制和算法。算法从网络利用率和用户感知两方面对影响流移动性选择的网络性能、负载情况、用户偏好以及P流的QoS需求等因素进行了全面的考虑,目的是为移动终端的每个IP流分配对其来说最合适的接入网。此外,本文定义了两个评价指标——接入网络负载均衡度和用户满意度,对算法的性能进行评估。最后,通过仿真验证了算法的有效性,并证实了P流移动性方案与垂直切换技术相比,能够达到更好的负载均衡效果以及更高的用户满意度。更多还原

【Abstract】 With the rapid development of wireless mobile communication technologies, the integration between heterogeneous wireless access networks has become the inevitable trend of future mobile communication. In the integration of heterogeneous wireless networks, how to make full use of the advantages of different access networks, and how to provide seamless continuity for the mobile terminals in a variety of heterogeneous network overlapping area, are hot issues in the research for heterogeneous wireless networks’integration. With the Multi Access Packet Data Network Connectivity and IP flow mobility introduced by3GPP, an operation mode with finer granularity for handover has been provided, at the same time opening a new era for the integration of heterogeneous wireless networks.IP flow mobility makes it possible for a multi-radio UE that is connected to the EPS via different accesses simultaneously, sending and receiving different IP flows through different accesses. Besides, it allows to switching over a single IP flow seamlessly and selectively to a different access, meanwhile keeping the other ongoing IP flows on their original access.Based on the3GPP standard, we introduced the basic concept of IP flow mobility, along with the system architecture, solutions and some signaling procedures. After that, this paper studied the specific implementation mechanism and algorithm in research for IP flow mobility depending on different trigger modes.The existing ANDSF has some drawbacks that it provides inaccurate routing strategies to mobile terminals. An enhanced mechanism with three improvements has been proposed in this paper, providing a better strategy for terminal-based IP flow mobility.Through deeply studying multiple attribute decision algorithms, combined with the characteristics of IP flow mobility, this paper proposes a mechanism for network-based IP flow mobility, which includes a trigger process and a network selection decision algorithm based on each IP flow. Simulation results validate the flexibility and efficiency of our proposed mechanism, which can achieve a better network load balancing as well as a higher user satisfaction.更多还原