基于FPGA的光OFDM研究

发布时间：2019-05-13 08:08

【摘要】：作为21世纪经济和社会的重要支柱产业,通信网络已经为全球经济和社会带来重大的变革。随着高清视频、在线游戏等业务的发展,及“三网融合”和物联网新政的逐步实施,现有传输网络的承载压力逐步增大。高容量,低成本和高可靠性是对下一代网络的基本要求。正交频分复用(OFDM)技术是一项多载波调制技术,其子载波相互具有正交性,使得多路OFDM的子载波信号可以在同一光纤信道中传输,从而提高了信号的频谱利用率,具有信号速率高,抗干扰,色散补偿等优点。进一步随着DSP的逐步成熟与完善,使得高速光OFDM成为可能,大大降低实现的成本。这样就可以满足未来网络的高速率,低成本和高可靠的要求。本论文研究了OFDM技术的基本原理,实现高速实时的光OFDM信号调制。对信号调制方法、系统结构以及光OFDM系统参数进行了比较分析,主要工作及成果如下:(1)对OFDM技术的原理及其调制的关键技术进行研究,对其数学模型进行分析推导,为之后OFDM信号各个部分的调制进行铺垫。在目前光网络发展的基础上,分析了其能够成为未来实时光通信中的主导技术的优势。(2)对OFDM信号发射机的设计展开研究。目前国内对此的实验大多停留在传统的离线处理和低阶调制方面的研究,本设计采用先进的Xilinx Virtex5系列FPGA进行高速信号处理,实现了发射机的实时在线处理功能、使用高阶16QAM与1024点IFFT相结合的调制方式,单块FPGA的传输速率最高可达2.5Gb/s,若多块并行可达到更高的速率。与离线处理设备相比其具有更低的成本,从而有利于日后实现商业化。(3)搭建了2.5Gb/s的实时光OFDM系统,并对其传输性能进行仿真。包括对传输速率、传输距离及载波数量的分析。实验结果表明,系统在FFT设置为1024点,OFDM的子载波总数为512,光纤长度为1km时系统性能最优。
[Abstract]:As an important pillar industry of economy and society in the 21 st century, communication network has brought great changes to the global economy and society. With the development of high definition video, online games and other services, and the gradual implementation of "three networks integration" and the new deal of the Internet of things, the bearing pressure of the existing transmission network is gradually increasing. High capacity, low cost and high reliability are the basic requirements of next generation network. Orthogonal Frequency Division Multiplexing (OFDM) technology is a multi-carrier modulation technology, and its subcarriers are orthogonal to each other, so that the subcarrier signals of multi-channel OFDM can be transmitted in the same fiber channel, thus improving the spectrum efficiency of the signals. It has the advantages of high signal rate, anti-interference, dispersion compensation and so on. With the gradual maturity and improvement of DSP, high-speed optical OFDM is possible and the cost of implementation is greatly reduced. This can meet the requirements of high speed, low cost and high reliability of the future network. In this paper, the basic principle of OFDM technology is studied to realize high speed and real time optical OFDM signal modulation. The signal modulation method, system structure and optical OFDM system parameters are compared and analyzed. The main work and achievements are as follows: (1) the principle of OFDM technology and the key technologies of modulation are studied, and its mathematical model is analyzed and deduced. It paves the way for the modulation of each part of the OFDM signal. On the basis of the development of optical network at present, the advantages that it can become the leading technology in real-time optical communication in the future are analyzed. (2) the design of OFDM signal transmitter is studied. At present, most of the experiments in China are focused on the traditional off-line processing and low-order modulation. In this design, the advanced Xilinx Virtex5 series FPGA is used for high-speed signal processing, and the real-time on-line processing function of the transmitter is realized. By using the combination of high-order 16QAM and 1024 point IFFT, the transmission rate of single block FPGA can reach 2.5 GB / s, and the higher rate can be achieved if multiple blocks are parallel. Compared with off-line processing equipment, it has lower cost, which is beneficial to commercialization in the future. (3) the real-time optical OFDM system of 2.5Gb/s is built and its transmission performance is simulated. It includes the analysis of transmission rate, transmission distance and carrier number. The experimental results show that the system performance is the best when the FFT is set to 1024 points, the total number of subcarriers of OFDM is 512, and the fiber length is 1km.
【学位授予单位】：大连工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN791;TN929.53

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