基于802.11p的车辆通信系统频率同步研究与实现

Research and Implementation of Frequency Synchronization in Vehicle Communication System based on IEEE 802.11p

车联网作为移动互联网的重要组成部分,正在蓬勃发展,人们对于车联网中车辆通信的质量需求也越来越高。IEEE 802.11p作为车联网中车车/车路协同通信的主要技术标准,其物理层采用64点的OFDM技术。OFDM对频偏敏感,在车辆通信中,由高速运动造成的多普勒频移会对信号接收造成严重影响。因此,对802.11p中的频率同步研究具有重要意义。本文给出了一种在802.11p下适用于车辆通信的频率同步算法,再利用短训练符号做频偏粗估计的基础上利用导频做相位跟踪,并进行了硬件实现和使用验证。对于FPGA实现中遇到的一些问题给出了适用于硬件实现的解决方法,为车辆通信系统的研究与应用提供了借鉴。

As an important part of Mobile Internet, Telematics is booming and people’s require-ment of vehicle communication quality is higher. IEEE 802.11p is the main technical standard of V2V/V2I cooperative communication in telematics, the OFDM technology of 64 FFT points is used in its physical layer. OFDM is sensitive to frequency offset and Doppler frequency shift caused by high-speed movement in vehicle communication has serious effects on signal receiving. Therefore, the research on frequency synchronization of 802.11p has important significance. This paper presents a frequency syn-chronization algorithm in 802.11p which is suitable for vehicle communication and the algorithm is implemented on FPGA hardware and is verified. For some problems encountered in the implementation of FPGA, this paper gives some solutions and provides the reference for the research and application of ve-hicle communication system.