Research On Adaptive Transmission Optimization At Q/V Band Satellite For Beam Hopping

The high-throughput satellite system can effectively reduce the transmission cost per bit while greatly increasing the communication capacity,thereby effectively overcoming the disadvantage of the expensive satellite communication system.In recent years,it has received extensive attention and research.However,problems such as strong signal attenuation and lack of spectrum resources caused by the inherent long path of satellite communications will severely limit the performance of highthroughput satellite systems.High-throughput satellites using Q/V frequency bands and multi-beambased beam-hopping technology aim at higher spectrum efficiency and system capacity,effectively overcoming the above-mentioned key points.However,Q/V band high path loss and beam hopping resource allocation are issues that have to be considered when designing satellite communication systems.In view of this,this article analyzes the signal space propagation characteristics for the Q/V band high link attenuation,and focuses on rainfall.Attenuation,in order to improve the system link spectrum efficiency,research on adaptive coding technology is carried out for severe rain attenuation,and the simulation results are used to study the time slot resource allocation of beam-hop forward link under the influence of dynamic rain attenuation.The specific research content is as follows :Firstly,this thesis summarizes the development advantages of high-throughput satellite and the status quo at home and abroad.On the basis of pointing out that the frequency band expansion and multi beam hopping technology are the key technologies of high-throughput satellite,this thesis analyzes the link attenuation of Q/V band satellite communication signal in the process of propagation,focuses on the impact of rainfall on Q/V band satellite communication,and studies the link attenuation of Q/V band satellite communication signal based on ITU-R model.In order to adopt adaptive coding and modulation technology,the synthesis method of short-term and long-term rainfall attenuation time series in Q/V band is given,and the rainfall attenuation time series at Q/V band is obtained by simulation,and its effectiveness is verified,which lays a foundation for the later research on adaptive coding and modulation and hop beam resource allocation of satellite at Q/V band.Then it describes the commonly used anti rain attenuation strategy,analyzes the advantages of adaptive coding technology,as the information transmission fading compensation technology in satellite mobile communication,adaptive coding modulation effectively overcomes the link loss in the process of information transmission.This thesis introduces the basic principle and key components of adaptive coded modulation technology.In order to achieve the optimal adaptive performance,a mode selection method of adaptive coded modulation is designed.Aiming at the threshold method,which ignores the influence of transmission delay,a mode selection method with maximum spectrum utilization is proposed.Finally,according to the adaptive process under the influence of rainfall,the performance of the proposed optimization algorithm is verified by MATLAB simulation.Finally,when discussing the resource allocation of forward link in high-throughput satellite system with beam hopping technology,a new method of time slot resource allocation for beam hopping under dynamic rain attenuation is proposed,which is different from the case that the signal attenuation caused by rain is regarded as a fixed value when calculating the link attenuation in the past.Considering the impact of rain attenuation on link performance,a hop beam time slot resource allocation model is established to minimize the fairness principle of second-order differential capacity when adaptive coded modulation is used to dynamically adjust link rate.In order to solve the beam hopping time plan(BHTP)of the established objective function model,analyze the multidimensional of the solution space bhtp and the nonlinearity of the objective function,genetic algorithm(GA)is introduced to solve the problem.The simulation results show that the proposed resource allocation algorithm can improve the system capacity and business requirements under the condition of meeting the fairness principle.