基于多相滤波器组的光正交频分复用系统研究

发布时间：2018-06-09 11:04

  本文选题：高速长距离传输 + 相干光正交频分复用　； 参考：《电子科技大学》2014年硕士论文

【摘要】：面对如今高速和长距离的传输要求,相干光正交频分复用(CO-OFDM)系统提供了一系列的解决方案。CO-OFDM的保护间隔(CP)可抑制光纤色散效应引起的OFDM符号间干扰(ISI),但CP开销的增大会降低CO-OFDM频谱利用率。通过在接收端插入一种重叠频域均衡(OFDE)算法来补偿色散,可以减小保护间隔、提高频谱利用率,这种方案称为减小保护间隔OFDM(RGI-OFDM),但这种重叠频域均衡(OFDE)算法的复杂度很大。本文提出一种能有效平衡CO-OFDM频谱利用率和RGI-OFDM系统复杂度间关系的新型方案,它是基于多相滤波器组的多子带复用OFDM(SBD-OFDM)系统。该系统利用多相滤波器组将接收信号划分成多个平行的子带信号,使得每个子带信号具有速率低且频谱相对平坦的特性,因此SBD-OFDM不需要额外的色散补偿模块,从而既能降低CP开销,又可以节省不必要的系统复杂度。本文研究的主要研究成果为以下两个方面:一方面,基于多相滤波器组的多子带复用系统设计。该系统主要由三个部分组成,子带划分、多子带信号处理和多子带信号合成接收。依据多相滤波器组的特性,将输入信号划分成M个相等带宽的子带,然后对M个子带信号进行简要的处理,得到M个平行的频域子带信号,经过合成后回复到传统CO-OFDM所能接收的阶段。整个方案的设计要点包括滤波器组的选择、子带数目M的判定、子带信号FFT窗口的同步方法等等。另一方面,多子带复用系统的实验验证。设计完成后,搭建实验来验证该系统的性能。首先,搭建一个传统相干光正交频分复用系统,减小发送端CP,得到系统性能劣化的传输结果。分别将重叠频域均衡算法(OFDE)和多子带复用应用到该系统的接收端,测试和对比CO-OFDM、RGI-OFDM和SBD-OFDM三个系统的传输性能和系统复杂度。由实验证明,本文提出的基于多相滤波器组的SBD-OFDM是一个高效的传输方案,只需要很低的系统复杂度就能实现同样良好的传输性能。
[Abstract]:In the face of today's high-speed and long-distance transmission requirements, Coherent optical orthogonal frequency division multiplexing (CO-OFDM) system provides a series of solutions. The protection interval of CO-OFDM can suppress the inter-symbol interference caused by fiber dispersion, but the increase of CP overhead will reduce the spectrum efficiency of CO-OFDM. By inserting an overlapping frequency domain equalization (OFDE) algorithm into the receiver to compensate for dispersion, the protection interval can be reduced and the spectral efficiency can be improved. This scheme is called reducing the protection interval OFDMU RGI-OFDM, but the complexity of this overlapping frequency domain equalization algorithm is very large. In this paper, a novel scheme is proposed to effectively balance the relationship between the spectral efficiency of CO-OFDM and the complexity of RGI-OFDM systems. It is a multi-subband multiplexed OFDMS-OFDM system based on polyphase filter banks. The system uses polyphase filter banks to divide the received signals into a plurality of parallel sub-band signals, so that each sub-band signal has the characteristics of low rate and relatively flat spectrum, so SBD-OFDM does not require additional dispersion compensation modules. It can reduce CP overhead and save unnecessary system complexity. The main research results of this paper are as follows: one is the design of polysubband multiplexing system based on polyphase filter banks. The system consists of three parts, sub-band division, multi-sub-band signal processing and multi-sub-band signal synthesis reception. According to the characteristics of the polyphase filter bank, the input signal is divided into M sub-bands with equal bandwidth, then M sub-band signals are processed briefly, and M parallel frequency domain sub-band signals are obtained. After synthesis, it is returned to the stage which can be received by traditional CO-OFDM. The main design points of the scheme include the selection of filter banks, the determination of the number of sub-bands M, the synchronization method of FFT window of sub-band signals, and so on. On the other hand, the experimental verification of multi-subband multiplexing system. After the design is finished, an experiment is built to verify the performance of the system. Firstly, a traditional coherent optical orthogonal frequency division multiplexing system is built to reduce the CPS of the transmitter and obtain the transmission results of the system performance degradation. The overlapping frequency-domain equalization algorithm (OFDE) and multi-subband multiplexing (MBS) are applied to the receiver of the system. The transmission performance and system complexity of CO-OFDM RGI-OFDM and SBD-OFDM are tested and compared. Experimental results show that the proposed SBD-OFDM scheme based on polyphase filter banks is an efficient transmission scheme and can achieve the same good transmission performance with very low system complexity.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN713;TN929.11
，

本文编号：1999509