Research On Sparse Code Multiple Access Technology In Satellite Communication System

In recent years,people have become more and more demanding on communications,the demand for mobile data traffic has increased by thousands of times,and the demand for spectrum resources is also increasing.It can be found from the existing research results that the current spectrum resources are limited and scarce,and it is almost impossible to achieve by increasing the number of available spectrum.With its abundant spectrum resources,millimeter wave has become the focus of 5G communication technology research.However,millimeter-wave signals have problems of high transmission path loss,severe rain and oxygen attenuation,and poor penetration.Relaying is an important means to solve these problems and improve the connectivity of millimeter wave wireless networks.When the millimeter wave transmission is directly blocked,the relay forwards the information to obtain better network coverage and improve the millimeter wave network performance.At the same time,because the beamforming technology adopted by the millimeter wave network causes a non-negligible overhead,the relay detection and selection of the relay network has also become the focus of the millimeter wave relay network research.This paper first introduces the system model of the millimeter wave relay network,which mainly introduces the modeling of blocking.Based on this,the SINR coverage of the millimeter wave relay network is analyzed in detail using random geometric methods.Subsequently,considering the problem of blocking sharing between the cellular link and D2 D link,the blocking model was improved,and thus the coverage of the millimeter-wave relay network with two hops was improved.Through simulation comparison,the improvement research shows Superiority.Then,the theoretical model of relay detection and selection in millimeter wave wireless network is established,and two relay detection and selection schemes are designed.One of the two schemes is the relationship between the number of detections under disordered detection and the capacity expectation,and the other is the relationship between the number of detections under ordered detection and the probability that the capacity is greater than a certain threshold.And it provides different options for different design needs.In this way,the relationship between the number of relay detections and the capacity of the millimeter-wave wireless network in different detection scenarios is explored,and the innovative relay detection and selection methods are proposed.