TCP网络自适应有限时间拥塞控制

Adaptive finite-time congestion control for TCP networks

针对TCP网络存在系统不确定性和UDP流干扰的拥塞控制问题,使用反步方法提出一种自适应有限时间拥塞控制算法。为了便于控制器的实现,将TCP网络的系统参数和无响应UDP流干扰整合成一个总的不确定。然后设计了一种简单的自适应律去估计系统的总不确定,使得系统总不确定的界不必事先获得,而且减小了计算开销,满足了路由器高速处理分组的需求。基于反步方法和设计的自适应律给出了一种自适应有限时间拥塞控制算法。应用有限时间稳定性理论证明了瞬时队列长度能够在有限时间内收敛到期望的队列长度。使用网络模拟器-2对所提出的算法进行了验证,仿真结果表明该算法在各种网络环境下具有较好的有限时间稳定性和鲁棒性。

To solve the problem of congestion control in transmission control protocol(TCP)networks in presence of system uncertainty and user data protocol^UDP)disturbances,an adaptive finite-time congestion control algoritlim is proposed using the backstepping metliod.In order to facilitate the implementation of the controller,the systemparameters of TCP networks and unresponsive UDP flows were integrated into a lumped uncertainty.Then a simple adaptive Law was proposed to estimate the lumped uncertainty,by which the bound of the lumped uncertainty was not required to be known in advance,and by which the computation burden was reduced and the requirement of router processing high speed packet was guaranteed.Using the backstepping metiiod and the proposed adaptive law,an adaptive finite-time congestion control algorithm was proposed and the finite-time stability theory was used to guarantee that the instanta neous queue length can be regulated at a desired queue length in a finite time.The proposed algorithm was validated by the network simulator-2 and the simulation results demonstrate the superior finite-time stability and the robustness of the proposed algorithm in various network scenarios.