Estimation of sending rate of DCCP CCID3 flows based on jitter of probe packets on WLANs

When a mobile host transmitting real-time video traffic using DCCP CCID3 moves between two wireless LAN access points with different congestion situations, it is difficult to quickly change the transmission rate according to the changes of communication environment because controlling the sending rate depends on feedback information. To solve this problem, we recently proposed a predictive rate control mechanism for real-time video streaming with handover and have since been studying suitable rate estimation schemes for this mechanism. We have demonstrated that the sending rate can be estimated from the jitter of probe packets that are sent periodically to the wireless network by simulation. In this paper, we evaluate the relation between jitter and the DCCP sending rate in a real environment both with and without background traffic and RTS/CTS function. Experimental results demonstrate that the sending rate can be estimated from the jitter of probe packets sent every 200 msec with errors less than 25% of the DCCP sending rate in an IEEE802.11b WLAN with three DCCP sending nodes by enabling RTS/CTS.