Research On Adaptive Modulation And Coding In Satellite To Ground Communication Links

With the development of science and technology, people are increasinglyasking to be able to achieve a reliable and effective uninterrupted globalcommunication, satellite mobile communication has developed into a contemporaryindispensable communication measure with its advantages in the communicationdistance and coverage. With the growing demand of people, it will withstand a lotof pressure in the large volume of business, spectrum resources, which requires thedevelopment of the future mobile satellite communication technology to meet theneeds of different types of business, limited resources to achieve efficient andreliable information transmission. However, adaptive modulation and codingtechnology has become a new research direction in satellite mobile communicationtechnology with its good effects of link adaption.The AMC (Adaptive Modulation and Coding) technology of the satellite andground link communications in the satellite mobile communication fading channelis to assess the advantages and disadvantages of the channel state ensuring thetransmission performance requirements and the sender dynamically changes variousparameters of the signal, such as the transmission power of the signal and thecombined manner and combined method between the modulation mode and codingscheme to improve the performance of the system under different channelconditions.Firstly, in this paper,path loss,shadow fading and multipath fadingcharacteristic of the satellite mobile communication channel was analyzed and gavethe characterization forms of the three environments such as urban, rural and openspace in the Rice Channels; then the related technology of the basic principles of theAMC technology was described and analyzed, focusing on the modulation andcoding techniques; finally, the principles and key issues of estimating AMCtechnology based on the SNR was introduced and analyzed the performance of highand low-level modulation and coding scheme by comparing methods.Secondly, the implementation of the adaptive modulation and codingtechniques in the satellite and ground link communication under differentbusinesses was focused on, and the appropriate and selected switching thresholdmethods based on the channel estimation under different business was given, andthe method has been optimized; finally, simulation and analysis results ofmodulation and coding scheme of different operations in different contexts.Finally, the SNR estimation method in the AMC system was researched, andimplementation methods of the SNR estimation in Rice Channels was obtained; finally, the expression of the determined switching threshold under the knownestimated parameters was given.The results show that the AMC technology in different channel conditions anddifferent types of business can be adapted to the satellite mobile communicationfading channel environment and the efficient transmission of the different types ofbusiness information.