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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Mobility Management in Next Generation All-IP Based Wireless Systems

Xie, Jiang (Linda) 09 April 2004 (has links)
Next generation wireless systems have an IP-based infrastructure with the support of heterogeneous access technologies. One research challenge for next generation all-IP based wireless systems is to design intelligent mobility management techniques that take advantage of IP-based technologies to achieve global roaming between various access networks. To support global roaming, next generation wireless systems require the integration and interoperation of heterogeneous mobility management techniques. Mobility in a hierarchical structure or multilayered environment should be supported. The objective of this study is to develop new mobility management techniques for global roaming support in next generation all-IP based wireless systems. More specifically, new schemes for location management and paging in Mobile IP for network layer mobility support, and new schemes for location management and handoff management in heterogeneous overlay networks for link layer mobility support are proposed and evaluated. For network layer mobility support, a distributed and dynamic regional location management mechanism for Mobile IP is proposed. Under the proposed scheme, the signaling burden is evenly distributed and the regional network boundary is dynamically adjusted according to the up-to-date mobility and traffic load for each terminal. Next, a user independent paging scheme based on last-known location and mobility rate information for Mobile IP is proposed. The proposed scheme takes the aggregated behavior of all mobile users as the basis for paging. For link layer mobility support, an IP-based system architecture for the integration of heterogeneous mobility management techniques is proposed. Three location management schemes under this IP-based architecture are proposed. All the three schemes support user preference call delivery which is a very important feature of next generation wireless communications. A threshold-based enhancement method is also proposed to further improve the system performance. Finally, a hybrid resource allocation scheme for handoff management in wireless overlay networks is proposed. Under this scheme, the overall system resources can be optimally allocated when mobile users are covered by multiple overlay networks.
52

Měření vzdáleností mezi stanicemi v IP sítích / Distance measurement between nodes in IP networks

Šimák, Jan January 2010 (has links)
This thesis deals with delay prediction issue between nodes on the Internet. Accurate delay prediction helps with choosing of the nearest internet neighbor and contributes to effective usage of network sources. Unnecessary network load is decreased due to algorithms of delay prediction (no need for many latency measuring). The thesis focuses theoretically on the three main algorithms using coordinate systems - GNP, Vivaldi, Lighthouses. Last one is at the same time the main subject of the thesis too. Algorithm Lighthouses is explored in detail theoretically and in practise too. In order to verify the accurate of delay prediction of Lighthouses algorithm the simulation application was developed. The application is able to compute node coordinates of synthetic network using Lighthouses algorithm. Description of simulation application and evaluation of simalution results are part of practice part of this thesis.

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