Applying router-assisted congestion control to wireless networks: Challenges and solutions

Router-assisted explicit-feedback congestion control protocols have recently been introduced to overcome the inefficiency problem of TCP in high bandwidth-delay product (BDP) wired networks. However, two main challenges are encountered when applying this kind of congestion control to wireless networks. One is how to distinguish the two kinds of packet loss (non-congestion-related loss and congestion-related loss) in lossy wireless networks as well as how to react to them accordingly and properly. The other is how to probe the unknown bandwidth capacity of a wireless link which is required in calculating router feedback. Through detailed analysis of these challenges, we have proposed some practical and novel enhancements on router-assisted congestion control for wireless environment. We have also implemented these enhancements in a router-assisted congestion control protocol called QFCP. Simulation results using ns-2 show that it can fairly allocate wireless bandwidth resource in heterogeneous networks.