Abstract: Streaming media and IP Phone applications have experienced rapid growth in recent years. These multimedia applications, however, may cause congestion in the Internet and thus threat the data transmission of other applications. Recently, TCP-friendly Rate Control (TFRC) is proposed as a congestion control scheme for multimedia applications to address this problem. In wired networks like the Internet, TFRC works very well. However, in wireless networks, the sending rate of TFRC will degrade abruptly because it suffers from the bit error occurred in wireless transmission. Therefore, a research issue arises: how to improve the congestion control mechanism of TFRC in wireless networks? In this paper, we introduce two solutions to this problem – ZBS and TFRC Veno. Through simulation, we find that: (1) in wireless networks, both ZBS and TFRC Veno achieve much higher throughput than TFRC; (2) in wired networks, TFRC Veno shows better TCP-friendliness than ZBS. Therefore, we believe that TFRC Veno is a better solution to address the abovementioned problem.

摘要： 最近几年来，流媒体和IP电话经历了非常迅速的发展。这些多媒体应用的大规模普及可能会在Internet造成拥塞，从而威胁其他应用的数据传输。TFRC是最近几年提出的一种专门针对多媒体流在Internet中传输的拥塞控制方案。 在有线网络如Internet中，TFRC效率很高，然而在无线网络中，TFRC的发送速率会因传输造成的比特错误而急剧下降。因此，如何在无线网络中改善TFRC的拥塞控制机制便成了当前需要解决的一个前沿课题。本文介绍了针对这一问题的两种解决方案 – ZBS和TFRC Veno,并且通过仿真分析，指出ZBS和TFRC Veno在无线网络中都能获得比TFRC更高的吞吐率，而在有线网络中TFRC Veno则表现出比ZBS更好的TCP友好特性。因此，TFRC Veno是针对该问题的更为有效的解决方案。