基于ROF的光载毫米波信号发生与传输特性研究

发布时间：2018-04-09 13:41

本文选题：ROF　切入点：光载毫米波　出处：《吉林大学》2015年硕士论文

【摘要】：ROF(Radio over Fiber)技术融合了“光纤通信”与“无线通信”两者的优势,为目前用户大容量、高带宽及移动性等需求提供了理想的解决方案,由于光毫米波生成与传输技术是ROF技术中的关键,所以本文研究内容核心是光载毫米波信号的产生方式与链路性能分析,主要研究内容概括为以下几点:第一,本文对ROF毫米波产生方式的国内外研究现状做了一个总结,理论分析了几种主流的毫米波产生原理,如:直接调制技术、光学外差技术、相位调制技术、利用非线性效应产生毫米波技术及外部调制技术等,并针对这几种方案的优点与不足分别进行了讨论,进而提出了基于马赫增德尔调制器(MZM)外部调制技术产生毫米波的优势。第二,基于MZM的外部调制技术产生毫米波的几种常见形式,如:双边带(DSB)、载波抑制双边带(OCS)、单边带(SSB)做了理论研究,并通过Optisystem7.0软件,对以上三种毫米波产生方式分别进行了仿真模拟。第三,本文对传统外部调制技术中两种典型的色散效应:“周期性衰落效应”及“码元缩窄效应”做了详细的理论推导及仿真分析。首先通过Optisystem7.0软件,建立了常见的双边带(DSB)、单边带(SSB)及载波抑制双边带(OCS)等三种光载毫米波产生系统模型,然后对这三种系统所存在的色散现象及系统性能进行了详细的理论研究及仿真分析。通过Optisystem仿真,我们得到了DSB、SSB和OCS光毫米波在经过不同距离下的光纤传输后的模拟眼图,结果发现,随着传输距离增加,眼图质量逐渐变差,“眼睛”趋于闭合,说明光纤色散限制了光毫米波信号的传输距离。第四,为了抑制传统外部调制法中“周期性衰落效应”及“码元缩窄效应”所带来的色散效应,本文提出了一种新型的单边带调制方案。本文从理论分析结合仿真模拟验证了该技术不仅可以有效抑制光纤色散对ROF系统传输性能的影响,并且提高了信号传输距离。具体实现过程:首先从理论上推导了该方案克服“码元缩窄效应”的实现过程;然后通过Optisystem仿真,得到了光毫米波在经过不同光纤传输距离后的模拟眼图,结果发现,在新型的调制方案中,当传输距在90km时,眼图质量仍然很好,当传输距离在100km时,眼图质量已经开始下降。相比传输系统来看,本文提出的新型单边带调制方案能很好地抑制“周期性衰落问题”和“码间干扰问题”。在长距离传输质量方面,具有很明显的性能改进。
[Abstract]:ROF(Radio over Fibertechnology combines the advantages of "optical fiber communication" and "wireless communication" to provide an ideal solution to the current needs of large capacity, high bandwidth and mobility.Because optical millimeter wave generation and transmission technology is the key of ROF technology, the core of this paper is the generation mode and link performance analysis of optical millimeter wave signal. The main research contents are summarized as follows: first,In this paper, the domestic and international research status of ROF millimeter wave generation is summarized, and several mainstream millimeter wave generation principles are theoretically analyzed, such as direct modulation, optical heterodyne, phase modulation, and so on.The advantages and disadvantages of these schemes are discussed, and the advantages of the external modulation technology based on MZM are proposed.Secondly, several common forms of millimeter-wave generation based on external modulation technology of MZM, such as two-sided band-band MZM, carrier suppressed-two-sideband (MZM), single sideband (SSB), are studied theoretically, and Optisystem7.0 software is used.The above three millimeter wave generation methods are simulated separately.Thirdly, in this paper, two typical dispersion effects in traditional external modulation techniques, namely "periodic fading effect" and "symbol narrowing effect", are derived and simulated in detail.Firstly, three kinds of optical millimeter-wave generation models are established by using Optisystem7.0 software, such as two-sided band Optisystem7.0, single sideband sideband (SSBs) and carrier suppression two-sided band band (Optisystem7.0).Then the dispersion phenomenon and system performance of these three systems are studied and simulated in detail.Through the Optisystem simulation, we get the simulated eye diagram of the optical millimeter wave of DSB-SSB and OCS at different distances. The results show that the quality of the eye image becomes worse with the increase of the transmission distance, and the "eye" tends to close.The dispersion limits the transmission distance of millimeter wave signal.Fourthly, in order to suppress the dispersion effect caused by "periodic fading effect" and "symbol narrowing effect" in traditional external modulation, a new single-sideband modulation scheme is proposed in this paper.The theoretical analysis and simulation results show that the proposed technique can not only effectively suppress the influence of fiber dispersion on the transmission performance of ROF systems, but also improve the signal transmission distance.The realization process: firstly, the realization process of the scheme to overcome the symbol narrowing effect is deduced theoretically, and then through Optisystem simulation, the simulated eye diagram of the optical millimeter wave passing through different optical fiber transmission distance is obtained, and the result shows that,In the new modulation scheme, when the transmission distance is at 90km, the quality of the ophthalmogram is still very good, and when the transmission distance is at 100km, the quality of the ophthalmogram has begun to decline.Compared with the transmission system, the new SSB modulation scheme proposed in this paper can suppress "periodic fading problem" and "inter-symbol interference problem" well.In the long distance transmission quality, there are obvious performance improvements.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN929.1

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