Researches And Simulation Of QoS Based On The Satellite Communication Ground Access Device

Satellite communication has already been applied to many domains due to its wide coverage, long communication distance, high communication capacity and broad transmission bandwidth. However, the properties of satellite link in satellite communication system make network congestion happen frequently, which leads to higher package lost rate and lower communication quality.The satellite communication ground access device is a part of ground segment in Satellite communication system, whose basic functions are routing and forwarding business data, as well as network management. A detailed description is given on how to implement the routing service module, which supports bridging, routing, regrouping IP package, forwarding manage data, running serval datalink layer protocol, as well as guaranteeing QoS. Based on the routing module, a new QoS solution for the application is put forward. In satellite communication, QoS measures are taken to guarantee to access device for traffic shaping so as to relief the network congestion in space segment. Thus, the package lost rate can be lowered to improve the quality.Two typical senarions are simulated with NS2 for network congestions and high package lost rate. The active queuing schedule algorithm is used to solve network congestion resulting from asymmetry bandwidth of up-link and down-link in satellite link, and the fair queuing schedule algorithm is used to solve the problem of high package lost rate which is due to the long delay of satellite link. By analyzing the simulation and comparing the QoS parameters, the problems above can be well resolved.