Research On Tactical Network Congestion Control Techonology

With the increase of the network size and the complexity of network structure, especially thesubstantial increase of number of nodes on modern battlefield, the rapid growth of the informationmake congestion problem become the bottleneck of effective information transmission in tacticalnetworks. The original congestion mechanism can not meet the quality of service, and the congestionoccurred directly on routers, therefore, the study about congestion control strategy on routers issignificative. This paper presents a research about the active queue management (AQM) algorithmaiming at the characteristics of tactical network. Main contributions are giving as follows:Firstly, the reasons in the tactical network congestion and the existing congestion controlstrategies are analysed. Then the tactical network congestion control model is established bylinearizing the nonlinear model on TCP window based on the fluid theory. Existing classical activequeue management algorithms including RED、REM、PI are used to manage the tactical networkcongestion control, simulation shows the performance of these algorithms.Secondly, in order to compensate the deficiencies of these algorithms, intelligent control theoryis introduced to improve the active queue management algorithm. An improved single neural PIDalgorithm combined with identification-free adaptive control algorithm is proposed, and the neurongain K can be adjusted dynamically. In addition, in order to improve the quality of the controller, theadjustment factor is designed to adjust the learning rate of neuron weight.Thirdly, fuzzy control theory is further quoted in the controller design, the error of rate and thequeue length are chosen as congestion indication to design the fuzzy controller. It is not only improvethe response speed, with fuzzy controller and PI controller combined together, the system achieveshigher stability.At last, sliding mode theory is introduced to design controller due to the complex changeabletactical network and nonlinearity of the system, the sliding congestion controllers for tactical wiredand wireless network are designed. Furthermore, in Ad hoc network, the mobility of nodes could leadto the topology change, which could cause the packet loss. So an observer is designed by consideringthe packet loss as input disturbance, simulation results indicate the method improved the robustness ofthe system.