Utilization-based Congestion Control: Improvement of Friendliness with TCP over Wireless Links

Conventional congestion control mechanisms like TCP New Reno fail to react appropriately to packet losses caused by error over the wireless link. Various modifications to loss based congestion control schemes have so far been proposed to overcome the corresponding performance degradation. In addition, the comparatively newer family of delay based congestion control mechanisms like Caia-Hamilton Delay (CHD), offer effective solutions for wireless link loss. However, all these approaches aim at improving the performance of the target connection without considering the overall network condition. As such, the other connections' performances suffer severely. Furthermore, for delay based schemes, it is not possible to determine the most accurate value of the queuing threshold intuitively. In this paper, we propose a new end-to-end congestion control mechanism that we name as Utilization-based Congestion Control (UCC) in order to overcome the above issues. UCC provides a solution based on the utilization at the bottleneck link. It is free from critical parameters like queuing threshold and is friendly to other flows over wireless links when deployed together. Simulation results show that (i) UCC can yield a performance improvement of 250% or more compared to conventional loss-based schemes over wireless links and (ii) it is friendly to conventional loss-based congestion controls over wireless links.