Summary: | 碩士 === 國立臺灣大學 === 電信工程學研究所 === 100 === In recent years, with the rapid development of wireless local networks, we are allowed to enjoy various convenient services with different handset device. Service providers such as telecommunication companies purvey diverse multimedia contents. Up to now, these contents were mainly transmitted to terminal user via unicast transmission which highly constrain the service types and reduce the network efficiency. Identical content needed by multiple users in local area can be sent simultaneously with multicast transmission and utilize the wireless channel better. However, due to lack of multicast support and feedback mechanism in current IEEE 802.11 networks, those services are impossible to be implemented. Therefore, IEEE 802.11aa task group is now engaged in basic multicast protocol. In this thesis, we implement different feedback mechanisms based on IEEE 802.11aa draft and compare their efficiency to baseline mechanism in the draft. Moreover, we realize a Linux-based testbed with modified wireless WLAN card driver and evaluate all mechanisms above by experiment in real life environment. We also show our design''s performance is better than baseline mechanism and can be well apply to real applications.
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