The Research Of TFRC Congestion Control Mechanism Base On Loss Differentiation Algorithm

With the wireless network communicate and the multimedia application of wireless broadband become a hotspot,the transmission of wireless network in real time multimedium has become an important application area.However,because of the wireless network's own limitation,such as,decline in transmission channel fluctuation in bandwidth,high bit-error rate of channel,the limitation of delay jitter and so on,the wireless network is difficult to achieve the high-quality real-time audio and video which is under the circumstances of wired,even in the wireless broadband environme nt.TCP-Friendly protocol is a good mechanism which being applicable to the wired network's real time multimedia transmission,but in applying to the wireless network, the lower performance is a major problem.Therefore,in order to develop real-time multimedia services in the wireless networks rapidly,it is necessary to improve the real-time transport protocol of multimedia communication in wired network,which make these protocol have good congestion control mechanism to ensure real-time multimedium's quality of service (QoS).In recent years,a variety of TCP-Friendly protocols and algorithm in real-time multimedia transmission has been extensively studied,and TFRC (TCP-Friendly Rate Control) protocol which is one of the most successful TCP-Friendly protocols is the focus of this thesis.First of all,this thesis research TFRC's running mechanism in depth and analyse TFRC protocol's performance in the wireless network by the experiment.Results have shown,because TFRC lacks the mechanism which can distinguish the type of packet loss,resulted in TFRC's poor performance.In order to provide real-time multimedia transmission with better QoS,it is need to resolve the issue.Therefore,this thesis proposes introduce Spike loss differentiation algorithm into TFRC protocol,so that it can accurately distinguish the type of packet loss.According to the situation of network packet loss,the receiver judge network's state correctly and then send the information with the form of feedback packets to the sender,to make the sender make the appropriately congestion control process,so can reach the aim of improve TFRC's overall performance under the wireless network environment.By the simulation experiment of NS2,it validates the scheme which improve TFRC congestion control mechanism works well and manifest well in performance, achieves the aim of improve the TFRC congestion control mechanism.At the same time,not only decrease packet loss rate and delay jitter,but also maintain the basic characteristics of TCP-Friendly protocol.