基于FPGA的OCDMA二维电域编解码系统的设计与实现

发布时间：2018-07-15 19:11

【摘要】：随着互联网时代的到来,各种新业务的出现使得人们对于接入网带宽需求呈指数级增长,中国的光纤通信进入了高速发展期,主要目标为实现高宽带、大容量、长距离传输和智能全光网络。OCDMA(光码分多址)技术凭借其独有的保密性、高拓展性、可随机异步接入、具有软容量及多用户共享信道等诸多优点,成为光纤领域下一代接入网技术中极具潜力的方案之一。本文围绕OCDMA二维电域编码系统中的关键技术进行研究,论文主要内容如下:1.综述了几种常见的OCDMA光学一维和二维编解码器的结构与工作原理,并分析了各类光学编解码器性能的优劣。同时对一种电域空间编码一光域FBGs解码的电光组合编解码器进行了说明,详细的阐述了其结构和编解码原理,分析了电域处理OCDMA系统的优势。根据时域-谱域二维全光OCDMA系统的编解码技术原理设计了一种OCDMA二维电域编解码器,对其构造方法及编解码原理进行了说明。2.设计了一种基于FPGA的OCDMA二维电域编解码系统。对系统中二维电域编解码模块、高速串行通信模块、帧封装模块、协助通道绑定模块等主要模块的设计原理及功能进行了详细的阐述,并结合VerilogHDL硬件描述语言、Modelsim、ISE等软件设计工具,以XilinxML605FPGA开发板为硬件平台,对各个子模块功能进行了 FPGA实现。最后将整个编解码系统各个模块进行级联综合,进行了两路用户数据的编解码测试,测试结果表明本文所设计的基于FPGA的OCDMA二维电域编解码系统能成功实现对用户数据的二维编解码功能。3.设计并开展了非相干OCDMA二维电域编解码系统实验。成功进行了两路用户数据的二维电域编解码系统实验,两路用户端数据速率均为312.5Mb/s,系统传输线速率为3.125Gb/s,4通道并行传输总量达12.5Gb/s,光纤传输距离为10KM。实验结果表明接收端均可正确解码出期望用户数据,且通过解码信号示波器眼图分析可知,系统码间串扰小,噪声影响较低,系统编解码性能优良。同时在实验系统硬件基础上,采用Xilinx提供的IBERTIP核对系统的高速传输通道进行了误码率测试,测试结果表明本文设计的高速传输通道传输性能良好,误码率较低。
[Abstract]:With the arrival of the Internet era, the emergence of various new services makes the demand for access network bandwidth increase exponentially. China's optical fiber communication has entered a period of high-speed development, the main goal is to achieve high broadband, large capacity, Long distance transmission and intelligent all optical network. OCDMA (Optical Code Division multiple access) technology has many advantages, such as its unique confidentiality, high expansibility, random asynchronous access, soft capacity and multi-user shared channel, etc. It has become one of the most potential solutions in the next generation access network technology in the field of optical fiber. This paper focuses on the key technologies of OCDMA 2-D electrical domain coding system. The main contents of this thesis are as follows: 1. In this paper, the structure and working principle of OCDMA optical one-dimensional and two-dimensional encoder and decoder are reviewed, and the performance of all kinds of optical encoder and decoder are analyzed. At the same time, a kind of electro optic combinatorial codec which encodes an optical domain FBGs is described, its structure and encoding and decoding principle are described in detail, and the advantages of the electric domain processing OCDMA system are analyzed. According to the encoding and decoding principle of two dimensional optical OCDMA system in time domain and spectrum domain, an OCDMA two dimensional electric domain encoder and decoder is designed, and its construction method and encoding and decoding principle are explained. An OCDMA 2 D electric domain coding and decoding system based on FPGA is designed. The design principles and functions of the main modules in the system, such as two-dimensional electrical domain coding and decoding module, high-speed serial communication module, frame encapsulation module and assist channel binding module, are described in detail. Combined with Verilog HDL hardware description language, Modelsimi ISE and other software design tools, using Xilinx ML605 FPGA development board as the hardware platform, the functions of each sub-module are implemented by FPGA. Finally, the whole coding and decoding system modules are concatenated and synthesized, and two user data coding and decoding tests are carried out. The test results show that the OCDMA two-dimensional codec system based on FPGA can successfully realize the two-dimensional codec function of user data. The two-dimensional encoder and decoder system experiment of incoherent OCDMA is designed and carried out. The experiment of two channels of user data encoding and decoding is successfully carried out. The data rate of the two channels is 312.5 MB / s, the transmission line rate of the system is 3.125 GB / s and the total amount of parallel transmission is 12.5 GB / s, and the optical fiber transmission distance is 10 km. The experimental results show that the receiver can decode the desired user data correctly, and through the analysis of the decoded signal oscillograph, it can be seen that the system has less crosstalk between codes, less noise, and the system has good coding and decoding performance. At the same time, on the basis of the hardware of the experiment system, the high speed transmission channel of IBERTIP check system provided by Xilinx is used to test the bit error rate. The test results show that the high speed transmission channel designed in this paper has good transmission performance and low bit error rate.
【学位授予单位】：广西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.1

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