Ad Aptivecoding And Modulation Technique In Broadband Satellite Mobile Communication

As the continuous development of modern Internet, especially the sergeant waves of mobile Internet, the requirements on HD video’s business, big data business are more and more urgent, and the demands for bandwidth services are higher and higher. Broadband satellite mobile communication is an important part of broadband communications. It is received great attention because it can break the restrict of space and offer a seamless, wide covering service anywhere. However, the transmission technology of broadband satellite mobile communication has posed great challenges. On one hand, as the high bandwidth network service to millions of mobile users, the new broadband satellite mobile communication system requires more transmission throughputs. On the other hand, the transmission quality of broadband satellite mobile communication will greatly reduce because of the weather attenuation, shadowing and multipath effects. In order to solve the above-mentioned contradiction, the Adaptive Coding and Modulation (ACM) technique emerged.Based on the research of DVB-S2broadband satellite communications protocol, the ACM technique of broadband satellite mobile communication is researched from three aspects:the choice of Modulation and Coding Schemes (MCS), the switching of MCS and the resource management of beam switching. The main work of this paper is as follows:(1) Based on the research of DVB-S2, the simulation architecture of physical layer is designed. The architecture includes channel model, signal to noise ratio (SNR) estimation module, coding and modulation module. The features of each modules are analyzed. The MCS is designed for the simulation architecture.(2) Based on the performance analysis of common MCS switching algorithms, this paper plans to propose an improved MCS switching algorithm based on variance modified average SNR and validates through simulation. Then a MCS switching algorithm based on Probability Estimation (PE) is proposed by the in-depth analysis of the random process of broadband satellite mobile channel. Through simulation, the BER and Throughput performances of each MCS switching algorithms are analyzed in broadband satellite mobile channel. Meanwhile the applicability of PE-based MCS switching algorithm is validated in the simulation architecture of broadband satellite mobile communication based on DVB-S2. Simulation results show good performances of BER and throughput with PE-based MCS switching algorithm.(3) On the basis of the research results of PE-based MCS switching algorithm, this paper introduces an common beam switching trigger mechanism based on geographic locations in broadband satellite mobile communication. An beam switching strategy is proposed based on MCS switching algorithm in broadband satellite mobile communication. Through simulation, the linking loads and the QoS is analyzed. Simulation results show that, better than the beam switching trigger mechanism based on geographic locations, the beam switching trigger mechanism based on MCS switching algorithm can effectively reduce the linking loads of broadband satellite mobile communication system and effectively increase the QoS of users.