光正交频分复用系统中信道估计及自适应技术的研究

项目名称： 光正交频分复用系统中信道估计及自适应技术的研究

项目编号： No.60872035

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 电工技术

项目作者： 邱昆

作者单位： 电子科技大学

项目金额： 31万元

中文摘要： 本项目将正交频分复用(OFDM)应用到光纤通信中，建立了单模和多模光纤的光OFDM的仿真平台，研究了光OFDM系统中信道估计、自适应技术和高速信号处理技术。软件平台在完整的理论模型的基础上采用模块化编程的思路，包括了五个关键的功能模块，能够开展关于光OFDM的多项研究。针对光纤通道估计，为了降低系统开销并同时保证系统性能，提出了通过线性插值来估计光纤通道响应；提出了新的导频方式来实现偏振解复用并降低光纤非线性的影响。针对自适应技术，在保证系统传输性能的情况下，提出了可变长保护间隔的方案以实现最大化的频率使用效率；针对发射机中采样速率可能变化的情况，在重新利用相位估计的导频信息的基础上，提出并实验验证了接收机采样速率跟踪的方案。针对高速信号处理技术，提出了一种新型函数信号变换法来降低峰均比；提出了自相位调制和交叉相位调制联合补偿的方案；提出了将受非线性散影响最大的子载波进行空置来避免四波混频串扰的方案；还开展了基于FPGA的数字信号处理的研究。

中文关键词： 光正交频分复用；自适应调制；信道估计；信号处理

英文摘要： This project has applied OFDM into optical fiber communication, built a software simulation platform for single-mode and multi-mode fiber optical OFDM systems, and investigated the channel estimation, adaptive techniques and high-speed signal processing for optical OFDM systems. Based on a complete theoretical model, the software platform has adopted the modular programming method, including five key function modules, and can be used to conduct various researches on optical OFDM. For the channel estimation, we have propsed a linear method to estimate the fiber channel response to guarattee a lower system overhead without system performance degradation, and proposed a new arrangement of the pilot symbols to realize polarization de-multiplexing and lower the effect of fiber nonlinearity. For the adaptive techniques, without system transmission performance degradation, we have proposed the adaptive length of cyclic prefix to maximize the spectral efficiency; due to the possible change of the sampling frequency of transmitters and based on the re-utilization of the pilot subcarriers for phase estimation, we have proposed and experimently verified a method for receivers to track the sampling frequency. For the high-speed signal processing, we have proposed a noval functional transformation to lower the peak-to-average ratio, proposed a joint compensation method for self-phase modulation and cross-phase modulation, proposed a method to avoid the four-wave mixing by nulling the subcarriers that are degraded most by the four-wave mixing, and conducted some digital signal processing research based on FPGA.

英文关键词： 光正交频分复用；自适应调制；信道估计；信号处理