Informationally Decentralized Video Streaming Over Multihop Wireless Networks
Informationally Decentralized Video Streaming Over Multihop Wireless Networks
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DOI：
10.1109/tmm.2007.902845
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发表时间：
2007-10
影响因子：
7.3
通讯作者：
Hsien-Po Shiang;M. Schaar
中科院分区：
文献类型：
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作者：
Hsien-Po Shiang;M. Schaar
在协议栈的不同层已经提出了各种分组调度、动态路由、错误保护和信道自适应策略，以解决多跳无线网络上的多用户视频流。然而，这些跨层传输策略只有在使用关于网络状况的准确信息并因此能够及时适应网络变化的情况下才能有效地优化。由于多跳无线网络的信息分散性，基于关于网络状态的全局信息对延迟敏感的视频流应用执行集中式优化是不切实际的。需要考虑采用基于及时信息反馈的传输策略的分布式解决方案。为了获得用于跨层适配的该信息反馈，我们部署了覆盖基础设施，该覆盖基础设施能够在不同的网络上(即，在预定的时间段内，在不同的跳数上)传递关于网络状态和引起的延迟的必要信息。在本文中，我们提出了一种基于从不同网络水平获取的本地信息反馈来优化的分布式流媒体方法。考虑到从更大范围内准确而频繁地反馈网络信息所带来的优点以及传输开销增加所带来的缺点，我们研究了在每个无线节点处的分布式跨层适配。基于信息反馈，我们可以估计来自不同优先级的分组在其解码截止日期到期之前无法到达目的地的风险。随后，调整了分组调度、重传限制和动态路由策略等各种传输策略，以联合考虑不同优先级类别的估计风险以及对失真的影响。实验结果表明，提出的基于及时信息反馈的动态路由策略在接收视频质量方面比现有的按需路由方案提高了2db以上。
Various packet scheduling, dynamic routing, error-protection, and channel adaptation strategies have been proposed at different layers of the protocol stack to address multi-user video streaming over multihop wireless networks. However, these cross-layer transmission strategies can be efficiently optimized only if they use accurate information about the network conditions and hence, are able to timely adapt to network changes. Due to the informationally decentralized nature of the multihop wireless network, performing centralized optimization for delay-sensitive video streaming application based on global information about the network status is not practical. Distributed solutions that adapt the transmission strategies based on timely information feedback need to be considered. To acquire this information feedback for cross-layer adaptation, we deploy an overlay infrastructure, which is able to relay the necessary information about the network status and incurred delays across different network ldquohorizonsrdquo (i.e., across a different number of hops in a predetermined period of time). In this paper, we propose a distributed streaming approach that is optimized based on the local information feedback acquired from the various network horizons. We investigate the distributed cross-layer adaptation at each wireless node by considering the advantages resulting from an accurate and frequent network information feedback from larger horizons as well as the drawbacks resulting from an increased transmission overhead. Based on the information feedback, we can estimate the risk that packets from different priority classes will not arrive at their destination before their decoding deadline expires. Subsequently, the various transmission strategies such as packet scheduling, retransmission limit and dynamic routing policies are adapted to jointly consider the estimated risk as well as the impact in terms of distortion of the different priority classes. Our results show that the proposed dynamic routing policy based on timely information feedback outperforms existing state-of-the-art on-demand routing solutions by more than 2 dB in terms of the received video quality.