Design And Implementation Of MAC Layer Based On Space-Sky Information Network

With the development of information and aerospace technologies, the strategy status of space is becoming more and more important in fields of politics, economic and military. Superiority of space information is the key to a strong nation and force, so our nation proposes to develop space-sky information network. Space-sky information network is the system composed of many satellite systems distributed on different orbits, which are interconnected according to the rule of maximum utilization of space information resource; furthermore, it composes an integrated network system with ground, sea and space.By studying the characteristics of space information network, this thesis mainly presents a backbone-non-backbone network model, and redesign and re-implement the MAC-layer of the space-sky information network on the basis of this network model. According to channel characteristics in the Space-sky information network, this thesis designs an new adaptive MAC-layer frame structure, and identifies specific frame length through simulation in Matlab. This thesis also expounds the MAC-layer implementation process based on Xilinx's FX70T FPGA chip. There are five modules in the MAC-layer, they are the MAC layer framing module, PKT_Queue module, Aurora modules, PCI Express module and MAC-layer frame-analysis module, then it simulates each module and the entire system under the Modelsim software, finally, it achieves MAC-layer high-speed data transmission based on Xilinx's ML507 development board and the IDT's high-speed PCI Express switching backplane.On the one hand, the MAC-layer mentioned in this thesis uses different fixed-length frames in different bit error rate, so it can raise the data transmission efficiency and network throughput; on the other hand, it can achieve the high-speed data switching and routing at the data link layer by the design of different domains of the MAC-layer frame, which can improve data transfer rate, and the maximum data transfer rate can be measured to 1.552Gbps in the specific hardware environment. In addition, the MAC-layer designed in this thesis maybe a reference for other high-speed data transmission network.