| Summary: | 碩士 === 國立臺灣大學 === 電信工程學研究所 === 93 === Accessing multimedia services, like video streaming, via Wireless LAN is expected to become one of the most popular approaches for video services. Though WLANs provide simple and low cost methods of connectivity, some properties like bandwidth instability, bursty packet loss, fading and multipath interference make video streaming over WLANs a challenge. When transmitting multicast video stream packets over WLANs, the Access Points do not adaptively adjust the video bit rate, physical bit rate and proprietary packet size according to the changeful channel condition. In 802.11 WLANs, when a mobile station (STA) moves from the original AP toward the new AP, the video playback may be interrupted. In other words, the existing system cannot provide seamless handover for video streaming.
In this thesis, we propose the adaptive multicast video streaming system with seamless handover support using smart APs. In such implementation, STA can move among the coverage of different APs and playback the video smoothly. Smart AP can adjust its forwarding policy of multicast packets, the transmission rate and packet size adaptively according to the feedback information of beacon signals generated by STA. In addition, we propose to employ AP-mode in the client’s terminal, to improve its controllability. The experiment results show that the proposed system outperforms the existing approach and achieves bandwidth efficiency.
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