With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable ...With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable video codecs has been proposed as an efficient architecture for video dissemination taking account of user and link diversities. However, in the wired/wireless combined best-effort based heterogeneous IP networks which provide more fluctuation in available bandwidth and end-to-end delay, the performance of streaming systems has been greatly degraded due to frequent packet loss, resulting from either wired congestion or wireless fading/shadowing. In this paper, we present a real-time embedded packet train probing scheme for estimating end-to-end available bandwidth so as to accomplish effective congestion and error control. This is facilitated by effective classification of packet loss sources, delay trend detection algorithm and flexible transmission rate of packets. Under the proper wireless channel modelling and estimation, our layered structure can allow appropriate subscription of video layers and adaptively insert necessary amount of forward error correction (FEC) packets so as to achieve QoS optimized system for scalable video multicasting.展开更多
Wi Fi网络下的视频多播传输问题是目前的研究热点,针对当前视频多播传输方案使得处于区域边界处的用户享受到的服务质量较低、可靠性差这一不足,提出一种基于多访问点(AP)协作的视频多播可靠传输方案。通过在多个AP间展开协作,每个AP可...Wi Fi网络下的视频多播传输问题是目前的研究热点,针对当前视频多播传输方案使得处于区域边界处的用户享受到的服务质量较低、可靠性差这一不足,提出一种基于多访问点(AP)协作的视频多播可靠传输方案。通过在多个AP间展开协作,每个AP可传输完全不同或部分不同的FEC编码报文,多播接收器利用空间和时间分集来提升性能。此外,我们还提出一种支持FEC码率自适应的资源分配算法,有效地提高了有限无线资源的利用率和视频质量。最后,通过全面的仿真实验评估了本文算法的有效性,与传统的单AP点多播算法相比,本文算法使用户满意率提升了37.1%。展开更多
文摘With the rapid growth of wireless broadband technologies, such as WLAN and WiMAX, quality streaming video contents are available through portable devices anytime, anywhere. The layered multicast system using scalable video codecs has been proposed as an efficient architecture for video dissemination taking account of user and link diversities. However, in the wired/wireless combined best-effort based heterogeneous IP networks which provide more fluctuation in available bandwidth and end-to-end delay, the performance of streaming systems has been greatly degraded due to frequent packet loss, resulting from either wired congestion or wireless fading/shadowing. In this paper, we present a real-time embedded packet train probing scheme for estimating end-to-end available bandwidth so as to accomplish effective congestion and error control. This is facilitated by effective classification of packet loss sources, delay trend detection algorithm and flexible transmission rate of packets. Under the proper wireless channel modelling and estimation, our layered structure can allow appropriate subscription of video layers and adaptively insert necessary amount of forward error correction (FEC) packets so as to achieve QoS optimized system for scalable video multicasting.
