Internet视频流中的自适应拥塞控制技术研究  

Adaptive Congestion Control Techniques for Internet Video Streaming

作　　者：黄伟红[1,2] 孙正兴[1,2] 张福炎[1,2] 

机构地区：[1]南京大学软件新技术国家重点实验室,南京210093 [2]南京大学计算机科学与技术系,南京210093

出　　处：《计算机学报》2001年第8期796-801,共6页Chinese Journal of Computers

基　　金：国家自然科学基金 (6 990 30 0 6 )资助

摘　　要：在当前 Internet的尽力而为服务模式下 ,网络拥塞和分组丢失不可避免 ,视频流应用必须使用有效的拥塞控制和差错控制机制来改善性能 .文中给出一个自适应拥塞控制与 RS编码差错修复机制相结合的端到端单播视频流体系结构 .所设计的自适应视频流协议 AVSP以一个参数可调的加权移动平均速率调整策略为核心实现拥塞控制 ,并使用 Gilbert模型进行分组丢失率估计用于决策 .仿真结果表明 ,AVSP具有对网络可用带宽波动的自适应能力和 Internet共享环境下的 TCP友好性 .A layered end-to-end unicast Internet video streaming architecture is presented. Specifically, an RS coding scheme is designed in error recovery layer against packet loss. A flexible congestion control scheme, AVSP (Adaptive Video Streaming Protocol) is designed in video transmission layer against bandwidth fluctuation. There are four states in AVSP, including: paused, quick-start, steady and congested. AVSP applies a weighted moving average rate adjust policy by examining whether the packet loss rate exceeds the threshold value or not. The alterable parameter setting of AVSP enables that it could be used under variant network conditions. Based on the Gilbert model and the serial number of packets, AVSP could get an estimated packet loss rate for next rate adjust decision. Its adaptation capacity could be compared with the Additive Increase and Multiplicative Decrease (AIMD) algorithm used in TCP in the same bandwidth fluctuation condition. Considering that the Internet is a shared environment, the inter-protocol characteristic (especially the TCP-friendliness) should be taken into consideration in AVSP design. The TCP-friendliness could be measured by an average throughput comparison in a simulation case with several concurrent AVSP flows and TCP flows. Simulation results demonstrate that AVSP has a good adaptation capacity against available band-width fluctuation, and act with TCP-friendliness in a shared environment.

关 键 词：INTERNET 视频流 自适应拥塞控制 数据传输 

分 类 号：TP393.4[自动化与计算机技术—计算机应用技术]