基于传输控制协议的无线自组网主动队列管理建模

主动队列管理（AQM）通常研究队列控制器的设计．作为被控对象，传输控制协议（TCP）往往利用网络仿真器（NS）的仿真实现，因此有必要研究无线自组网的TCP及AQM特性．基于TCP窗口加性增一乘性减算法及排队原理，推导了TCP窗口及队列的微分方程，再基于比例积分AQM控制，推导了拥塞丢弃概率的微分方程，通过建立联立微分方程组，提出了AdHoc网络TCP／AQM微分模型．对比仿真显示，新模型能较好地估计无线白组网的性能．模型研究也表明，网络跳数，无线丢失和过小的队列成为AQM性能瓶颈，队列信息则有助于TCP区分无线自组网的拥塞丢弃与无线丢失．

Modeling active queue management based on transmission control protocol in Ad Hoc network

The active queue management(AQM) is usually concerned with the queue controller design. As a controlled object, the transmission control protocol(TCP) is often realized by the simulation of Network Simulator(NS). Thus, it is necessary to study the characteristics of TCP and AQM in Ad Hoc network. Differential equations for the TCP windowsize and queue-length are developed based on the TCP window additive-increase multiplicative-decrease algorithm and the queuing principle. Next, the differential equation of the congestion-loss probability is derived based on the proportionalintegral AQM control. Then, the Ad Hoc network TCP/AQM differential model is proposed through the simultaneous differential equations. The comparison simulations show that the new model can estimate Ad Hoc network performance. The model research also shows that the number of hops, wireless loss and the very small queue become the bottleneck of the AQM performances. Furthermore, the queue information can help TCP discriminate between congestion loss and wireless loss in Ad Hoc network.