Estimation Of SNR In Ka Band Satellite ACM Communication System

It has experienced 50 years of development since satellite communication was presented in 60 s.Satellite communication,which has become a way has high quality of communication from the original analog low bandwidth communication method,has been widely used in emergence communication,Space-Earth Integration Network and many other aspects.As a high frequency satellite communication method,Ka band satellite communication has become a research hotspot because of its high working frequency and large bandwidth.In order to overcome the influence of rain attenuation in Ka band satellite communications,adaptive coding and modulation technology(ACM)is used to avoid wasting system resources,Signal-to-noise ratio(SNR)estimation,as an important part of ACM system,is particularly important for its selection of the link parameters according to the actual state of the current channel.To overcome the poor efficiency of the existing SNR estimation algorithm and the bad estimation effect in the high frequency satellite communication system,this thesis mainly studies and improves the SNR estimation algorithm which can be applied to the high frequency satellite communication system,making it suitable for the Ka band satellite adaptive coding and modulation communication system,and accurately estimate the current communication channel state.Based on the above discussion,this thesis has done the following research.Firstly,this thesis analyzes attenuation of the Ka band satellite communication signals during the propagation process,emphatically focuses on the analysis of rainfall effects on Ka band satellite communication.The technology of adaptive coding modulation is taken to solve the problem of rainfall effects,Introduces the physical layer structure of Ka band satellite adaptive coding and modulation communication system,channel model based on ITU-R model is studied in Ka band satellite adaptive coding modulation communication system.The sequence of SNR in different regions with different SNR ranges is obtained by simulation,which lays the foundation for the study of the algorithm of SNR estimation in Ka band satellite adaptive coded modulation communication system.Secondly,this thesis focuses on the study of the estimation algorithm of the SNR of separation symbol moment estimation and analyze its performance.Based on that,we improved the algorithm of separating symbol moments estimation,making it suitable for Ka band satellite adaptive coding and modulation communication system and improving its SNR estimation performance.At last,aiming at the problem of the impact of rain attenuation on the return information in estimation of channel state information in ACM system caused by the communication delay,the principle of echo state network is introduced in detail,and the estimated value of SNR is predicted by this network,overcoming the delay of SNR estimation in Ka band satellite ACM communication system.Moreover,modify the network parameters and improve the robustness of the network,reduce the "sick" frequency.Introduce the differential genetic algorithm,optimize the parameters with fewer iterations,and simplify the optimization process.