지연시간에 기반한 멀티미디어 전송율 제어 알고리즘 연구

Abstract

Recently, the study to improve the QoS(Quality of Service) of multimedia service has been done actively along with the increase of multimedia service. TFRC(TCP-Friendly Rate Control) is now noted for the congestion control algorithm for multimedia service. But TFRC has continuous loss of packets as it performs the congestion control after packet loss. This causes low QoS of multimedia service. Therefore the algorithm to control the transmission rate before packet loss occurs is required. The packet loss occurs mostly due to the network congestion. The network congestion happens when the number of packets incoming into router is bigger than that of packets which router can process. Thus, delay rapidly increases before packet loss. This thesis adjusts the transmission rate based on delay experienced by a receiver. Specifically, DBRC(Delay Based Rate Control) uses the current delay and information about whether delay increases or not. To test the performance of DBRC, NS-2 simulation tool was used for measuring the packet loss, delay, variance of transmission rate of DBRC and TFRC respectively. The testing result shows that DBRC had less packet loss and stable transmission rate and delay variation than TFRC.