Research On Doppler Frequency Shift Estimation And Compensation Based On Satellite Network

With the rapid development of terrestrial mobile communication systems,satellite networking communication systems are playing an increasingly important role in maritime vessels,communications in remote areas,and emergency communications in natural disasters.In particular,since the 3rd Generation Partnership Project(3GPP)confirmed the 5G network standard in 2019,the new generation of 5G-based satellite networking communication systems and their key and hotspot technologies have continuously aroused the research interest of experts and scholars.However,in the satellite communication process,the Doppler effect will cause the signal error rate to increase and the communication interruption,which brings serious threats to the communication performance.At the same time,Various channel interferences in the communication process will also cause deep fading of the received signal amplitude at the receiving end,causing data loss during information transmission and the original signal cannot be demodulated correctly.In this context,exploring how to reduce Doppler frequency shift and channel interference,and to estimate and compensate for Doppler frequency shift has very important theoretical value and practical significance.The main research contents of this article include:1.By analyzing the characteristics of the satellite network communication system and the ground mobile communication system,the 5G network technology and the satellite network communication system are integrated to build a new network communication mode,referred to as the virtual satellite cell network communication system,which is activated by one The centralized management and control unit and multiple distributed units.2.Analyze the traditional algorithm to reduce the Doppler frequency shift,combined with the characteristics of the virtual satellite cell network system,this paper uses the Centralized Control Unit to assist the User Equipment to quickly select the Distributed Unit with the smallest Doppler frequency shift,to reduce the Doppler frequency shift in satellite communications.Among them,for the different situations of whether the User Equipment and the Centralized Control Unit can be directly connected,this paper proposes two solutions for uplink and downlink interaction and broadcast channel to further ensure that the User Equipment always establishes a communication relationship with the Distributed Unit with the smallest Doppler shift.3.According to the functions of the Centralized Control Unit,combined with the transmission delay between the Centralized Control Unit and the User Equipment,and between the Centralized Control Unit and the Distributed Unit,analyze Relevant data of satellites and User Equipment in the simulation platform to achieve the purpose of accurate estimation and timely compensation of Doppler frequency shift values.4.Research and analyze the channel interference types and calculation methods involved in this article,derive the channel interference index calculation formula;Combine satellite and User Equipment related data and location distribution characteristics,optimize the channel interference coordination method,finally,a multi-frequency division algorithm is used to coordinate of the satellite networking channel interference.In view of the above research content,combined with a large amount of data from satellites and User Equipments,this paper conducted a simulation analysis.Compared with traditional methods,the Doppler frequency shift estimation algorithm based on Virtual Satellite Cell has a significant effect on reducing the Doppler frequency shift,thereby improving the quality of satellite communication links and the success rate of access.At the same time,this paper also simulates and validates the assumption that “the User Equipment have different geographic locations and different Doppler frequency shift values”,which provides a simulation reference for solving the effects of different geographic locations on the Doppler frequency shift.In addition,the simulation results show that the multi-frequency division algorithm effectively achieves channel interference coordination and ensures the reliability of signal transmission.