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Issue No. 01 - Jan. (2013 vol. 12)
ISSN: 1536-1233
pp: 21-34
Kate Ching-Ju Lin , Academia Sinica, Taipei
Wei-Liang Shen , Academia Sinica, Taipei
Chih-Cheng Hsu , National Taiwan University, Taipei
Cheng-Fu Chou , National Taiwan University, Taipei
Adaptation of modulation and transmission bit-rates for video multicast in a multirate wireless network is a challenging problem because of network dynamics, variable video bit-rates, and heterogeneous clients who may expect differentiated video qualities. Prior work on the leader-based schemes selects the transmission bit-rate that provides reliable transmission for the node that experiences the worst channel condition. However, this may penalize other nodes that can achieve a higher throughput by receiving at a higher rate. In this work, we investigate a rate-adaptive video multicast scheme that can provide heterogeneous clients differentiated visual qualities matching their channel conditions. We first propose a rate scheduling model that selects the optimal transmission bit-rate for each video frame to maximize the total visual quality for a multicast group subject to the minimum-visual-quality-guaranteed constraint. We then present a practical and easy-to-implement protocol, called QDM, which constructs a cluster-based structure to characterize node heterogeneity and adapts the transmission bit-rate to network dynamics based on video quality perceived by the representative cluster heads. Since QDM selects the rate by a sample-based technique, it is suitable for real-time streaming even without any preprocess. We show that QDM can adapt to network dynamics and variable video-bit rates efficiently, and produce a gain of 2-5 dB in terms of the average video quality as compared to the leader-based approach.
Streaming media, Visualization, Heuristic algorithms, Schedules, Protocols, Bit rate, Scheduling, QoS, Wireless video multicast, rate adaptation

C. Hsu, W. Shen, K. C. Lin and C. Chou, "Quality-Differentiated Video Multicast in Multirate Wireless Networks," in IEEE Transactions on Mobile Computing, vol. 12, no. , pp. 21-34, 2013.
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