Research On Synchronization And CFO Estimation Algorithm Of LTE-V System

LTE,as the new generation of mobile communication standard,is recognized by the majority of telecommunication operators and the commercial deployment has been globally proceeding in an organized manner.The rapid development of LTE emergence has triggered a large amount of top business and Internet applications.With the widespread LTE networks,automobile industry captures the opportunity of Internet of Vehicles(IoV)transformation.As the communication technology of IoV,IEEE 802.11p still has some difficulties in obtaining service with low latency and high reliability,especially in high-speed scenarios.Therefore,how to realize IoV wireless communication through LTE has become a hot spot in this stage of research.V2V is considered as the main type of IoV business and has significant research value.In V2V communications,transmitted signals would experience a wide variety of fading in complex communications environments.Unlike traditional LTE scenarios,V2V communications will face higher carrier frequency offset challenges due to Doppler effects in high-speed mobile environment and crystal oscillator errors.This study focuses on the random access synchronization algorithm and carrier frequency offset estimation in high-speed mobile environment of V2V communication.This paper builds a physical layer link model suitable for V2V communication based on the relevant protocols established in 3GPP for LTE-V and sidelink.At the same time,this paper studies and improves the physical layer random access synchronization and frequency offset estimation algorithm,making it suitable for V2V communication in high-speed mobile scenarios.For the random access algorithm,this paper analyzes the combined timing errors caused by the time and frequency offset on the access process and analyzes the characteristics of the ZC sequence.Based on the traditional design of the synchronization signal,this paper proposes a conjugate interleaved PSSS design scheme to reduce the timing deviation caused by the time and frequency offset.Finally,using the improved synchronization signal,we propose the superimposed PSSS and SSSS detection algorithms respectively to improve the accuracy and timeliness of synchronization detection.Through the simulation analysis of system miss detection rate,the correctness of synchronous detection algorithm is verified.To solve the problem of 4800Hz frequency offset in V2V scenario,this paper proposes Comb-DMRS based joint carrier frequency offset estimation algorithm.The algorithm uses Comb-DMRS and adjacent DMRS in series,which improves the estimation accuracy while expanding the effective range of frequency offset estimation.At the same time,the AR model based synchronization tracking algorithm improves the robustness of the estimation algorithm.Finally,the improved frequency offset estimation algorithm is simulated and analyzed in detail,and the performance of the algorithm is verified to meet the requirement of high reliability and low latency of LTE-V in high-speed mobile scenarios.