【摘要】：隨著社會(huì)的快速發(fā)展,人們對(duì)汽車的需求不斷的增長(zhǎng),道路通行的壓力也隨之增加。日益凸顯的交通安全隱患,使智能化的汽車服務(wù)備受各方的青睞,汽車互聯(lián)將是未來(lái)汽車電子行業(yè)發(fā)展的趨勢(shì)。提供全方位的消息共享服務(wù)和實(shí)時(shí)交通狀況,是車聯(lián)網(wǎng)最基本的功能。車聯(lián)網(wǎng)所提供的這些服務(wù)不僅僅只是融合了通信、服務(wù)、終端硬件的綜合體,它更是汽車商業(yè)鏈的催化劑。本論文以車聯(lián)網(wǎng)系統(tǒng)為研究的主體,針對(duì)車聯(lián)網(wǎng)系統(tǒng)中基帶處理的部分問(wèn)題展開研究,這對(duì)將來(lái)車聯(lián)網(wǎng)系統(tǒng)的實(shí)際應(yīng)用有著重要的意義。本論文主要完成的工作內(nèi)容如下:本文首先詳細(xì)敘述了車聯(lián)網(wǎng)系統(tǒng)物理層使用的OFDM技術(shù)的基本原理和特點(diǎn)。深入分析了同步誤差對(duì)OFDM系統(tǒng)造成的影響,并且利用仿真實(shí)驗(yàn)給出了誤差驗(yàn)證結(jié)果。此外,針對(duì)車聯(lián)網(wǎng)系統(tǒng)中媒體訪問(wèn)控制使用的防碰撞機(jī)制,在大量請(qǐng)求接入節(jié)點(diǎn)的環(huán)境中會(huì)出現(xiàn)低吞吐率的問(wèn)題,做出了相應(yīng)的研究分析。緊接著,本文以經(jīng)典的SchmidlCox算法為基礎(chǔ),重點(diǎn)研究了幾種同步算法。通過(guò)詳細(xì)的公式演算和推導(dǎo),分析出SchmidlCox算法度量曲線存在平臺(tái)區(qū)的缺點(diǎn),以及Minn算法的多側(cè)峰問(wèn)題。通過(guò)分析上述算法存在的缺陷,本文通過(guò)設(shè)計(jì)新的訓(xùn)練符號(hào)提出了改進(jìn)的基于訓(xùn)練符號(hào)的同步算法。該改進(jìn)的算法不僅消除了平臺(tái)區(qū)的影響,而且消除了多側(cè)峰的干擾。提高了符號(hào)定時(shí)的準(zhǔn)確性。最后通過(guò)仿真得到驗(yàn)證。然后,本文通過(guò)仿真分析了存在大量請(qǐng)求接入節(jié)點(diǎn)時(shí),系統(tǒng)吞吐率下降的情況。為解決這個(gè)問(wèn)題,本文將正交頻分多址復(fù)用的技術(shù)使用到車聯(lián)網(wǎng)系統(tǒng)的媒體接入層中,通過(guò)設(shè)計(jì)滿足基于OFDMA的CSMA/CA機(jī)制的接收機(jī)的模塊,仿真驗(yàn)證了該方法可以提高系統(tǒng)的吞吐率。最后,本文將車聯(lián)網(wǎng)系統(tǒng)設(shè)計(jì)的各個(gè)模塊使用FPGA來(lái)實(shí)現(xiàn)。FPGA作為現(xiàn)在通信電子技術(shù),以其高效、大數(shù)據(jù)運(yùn)算等特點(diǎn)被廣泛的應(yīng)用。文章給出了發(fā)射機(jī)和接收機(jī)的核心模塊設(shè)計(jì)和部分優(yōu)化算法。以實(shí)際應(yīng)用的FPGA仿真完成車聯(lián)網(wǎng)通信模塊,使得本文的設(shè)計(jì)更具有說(shuō)服力。
[Abstract]:With the rapid development of society, the demand for cars is increasing, and the pressure of road passage is also increasing. Because of the hidden trouble of traffic safety, the intelligent automobile service is favored by all parties, and the automobile interconnection will be the development trend of the automobile electronics industry in the future. To provide a full range of information sharing services and real-time traffic conditions, is the most basic function of the car network. These services are not only a combination of communications, services, and terminal hardware, but also a catalyst for the automotive business chain. In this paper, the main body of this paper is the vehicle networking system, aiming at some problems of baseband processing in the vehicle networking system, which is of great significance to the practical application of the vehicle networking system in the future. The main contents of this paper are as follows: firstly, the basic principles and characteristics of OFDM technology used in the physical layer of the vehicle networking system are described in detail. The influence of synchronization error on OFDM system is analyzed deeply, and the result of error verification is given by simulation experiment. In addition, aiming at the anti-collision mechanism used in the media access control of the vehicle networking system, the problem of low throughput will appear in the environment of a large number of request access nodes, and the corresponding research and analysis are made. Then, based on the classical SchmidlCox algorithm, this paper focuses on several synchronization algorithms. Based on the detailed formula calculus and derivation, the shortcomings of the SchmidlCox algorithm in the platform region and the multi-side peak problem of the Minn algorithm are analyzed. By analyzing the shortcomings of the above algorithms, this paper proposes an improved synchronization algorithm based on training symbols by designing new training symbols. The improved algorithm not only eliminates the influence of platform area, but also eliminates the interference of multi-side peaks. The accuracy of symbol timing is improved. Finally, it is verified by simulation. Then, the throughput of the system is analyzed by simulation when there are a large number of request access nodes. In order to solve this problem, the orthogonal frequency division multiple access (OFDM) technology is used in the media access layer of the vehicle networking system, and the receiver module which satisfies the CSMA/CA mechanism based on OFDMA is designed. Simulation results show that the proposed method can improve the throughput of the system. In the end, every module of the vehicle networking system is implemented by FPGA. As a communication electronic technology, FPGA is widely used for its high efficiency, big data operation and other characteristics. The core module design and partial optimization algorithm of transmitter and receiver are given in this paper. The design of this paper is more persuasive to use the FPGA simulation to complete the communication module of the vehicle network.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U495

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

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本文編號(hào)：2443443