| 題目：Advanced Routing Techniques for Robust Video Data Communications 主講人：Prof. KIEN A. HUA (IEEE Fellow) Department of Electrical Engineering & Computer Science University of Central Florida Orlando FL 32816-2362 時間：101年03月07日 (星期三13:30-15:30) 地點：三峽校區社科大樓社1F06教室 摘要： In this presentation, we discuss two network communications research projects at UCF Data Systems Lab: Robust and Scalable Wireless Mesh Access Network: In multi-hop wireless mesh access networks, maintaining one dedicated stream per user severely limits scalability and can lead to network collapse in the face of a sudden surge in popularity of certain videos. Finding solutions for this problem is also vital for services which experience the so-called 80-20 access pattern, where about 80% of demand is for around 20% of videos. Existing multicast solutions like Patching are unsuitable because the video server generally cannot participate in the mesh network protocols. Proxy servers are similarly unsuitable because they reduce strain on the video server but not within the mesh access network itself where they appear as just another server. To address these problems, intelligent mesh nodes can monitor the video streams to detect duplication. By employing a merging buffer, the recent video data from an older stream can be reused in a newer copy of the stream. Merging takes place independently at the mesh nodes as needed throughout the network, incrementally constructing a wireless multicast tree which is able to evolve to service new requests and adapt to the dynamics of user mobility. This approach saves precious wireless resources and improves the robustness of the network without requiring cooperation with either the video source or the users. Mercury-Like Routing for High-Mobility Wireless Ad Hoc Networks: Supporting high mobility is essential to mobile ad hoc networks in a wide range of emerging applications such as vehicular networks. Communication links of an established communication session that extends between source and destination nodes are often broken under a high mobility environment. Although a new communication route can be established when a link break occurs, repeatedly reconstructing new routes incurs delay and substantial overhead. A new paradigm based on communication paths can be employed to address this limitation. A communication path is a dynamically-created geographical area that connects the source and destination nodes. The routing functionality of a communication path is provided by the physical nodes (i.e., mobile devices) currently within the geographical region served by the path. These physical nodes take turns in forwarding data packets for the path. Since a path can be supported by many alternative nodes, this scheme is much less susceptible to node mobility. In addition to its application to mobile ad hoc networks, this communication model can also be utilized to design highly robust wireless mesh access networks for highly-mobile applications. |
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