Baseband Signal Processing Design And FPGA Implementation Based On OFDM In IOV System

With the rapid development of mobile Internet,intelligent transportation system play an important role under the background of the popularization of Internet plus.In order to solve the problems of traffic congestion,road planning and road obstruction,the IOV system came into being.In order to struct connection between cars and roadside unit in the roadside,IOV system proposed to install the car unit in the car and install roadside unit in the roadside,It can also help traffic management platform to allocate flow allocation reasonable,make great use of road resources,monitor real-time vehicle violations.IOV system is a major trend in the development of the wisdom of the national transport system.This thesis mainly focuses on the design and research of the standard on physical layer of 802.11 p communication in the underlying communication protocol of the car network.The main contents are as followsFirstly,after a briefly introduction of the 802.11 p and OFDM related theories applied in the car network system.The difference between 802.11 p and 802.11 a is analyzed,and the influences of synchronization error is discussed,and we will also do research analysis and implementation on algorithms.Secondly,the synchronization algorithm in the improved OFDM system is analyzed and realized.Firstly,we study and analyze two classical synchronization algorithms,namely Schmidl & Cox synchronization algorithm and Park synchronization algorithm.But these two algorithms share a problem that Peak appeared in the platform area,and vice peak is higher than we want.In this paper,we propose an improved synchronization algorithm based on PN weighting,it can eliminate the deputy peak of the Park algorithm and the platform area of Schmidl & Cox algorithm.The improved algorithm have one main peak on the timing measurement curve,and particularly sharp,thus improving the timing accuracy,and we applied the improved algorithm to the 802.11 p standard.In addition,the Schmidl & Cox synchronization algorithm already has a good MSE on the carrier frequency offset,so the idea of its carrier frequency offset synchronization has been used.Then,the detailed research and implementation of the transmitter baseband processing FPGA implementation,strictly in accordance with the 802.11 p standard PPDU frame structure to achieve,the ultimate goal is to achieve the transmitter output PPDU frame,PPDU frame is also up and down before the last Of the physical layer.This paper analyzes the principle of each part of PPDU frame and the FPGA generation process in detail.Finally,the synchronization algorithm is discussed in detail in FPGA,including symbol timing synchronization and carrier frequency offset synchronization,because the theoretical analysis of the formula in the hardware platform to achieve there will be some restrictions,so need to undergo a certain transformation,and ultimately to the theory Applied to the actual.