Design And Implementation Of Ground Gateway For Satellite Switching Communication System

With the rapid development of satellite communication, using satellite for multi-media communication has became a research point. A new generation of board-band multi-media satellite communication system has been developed, its feature are in-satellite switch and process, that is shift the switch and route function to the satellite, in this way the usage of downlink has been greatly improved.Combined with specific project, this paper first analyzes the feature of ATM and Ethernet and the defects of applying these technologies directly to satellite communication system. According to the specific requirement of the satellite communication, a method of combining the ATM and Ethernet together is putted forward. That is on the LAN side on the ground of the smooth upgrade of network, the Ethernet is adapted; while on the satellite side, the ATM is used due to its good support QoS and multi-media services.In this system, the ground gateway serves as the bridge for the two sub-communication system. Its main function can be generalized into two parts.â‘ On the data transmit part, the ground gateway receive Ethernet frame from LAN and adapt it into AAL5 frame, then slice the frame into ATM cells and send them to the satellite; On the other side, the ground gateway receive ATM cell from satellite and assembly them into Ethernet frame and then send it to LAN.â‘¡On the control part, the ground gateway acts as agent for the terminal of the LAN and sets up link with other ground gateways. So the connection-based communication is realized by the gateway. Through the ground gateway the interaction of connectionless Ethernet network and the connection-based ATM network is realized.Then, the paper analyzes the functional requirement of the ground gateway and gives the general design of the architecture of the gateway. Because the gateway is rather complex, we first introduce the BUS module, the queue and schedule module. Then we take the example of adapting one Ethernet frame into AAL5 frame and explain the process of how to use the gateway as agent to set up virtual link. After, the paper analyzes some of those functional modules and gives detailed hardware realization scheme. Last, the paper analyzes the result of FPGA hardware realization, the simulation result and gives the debug process.