收稿日期: 2015-04-22
网络出版日期: 2017-02-28
基金资助
国家自然科学基金资助项目(61132004, 61275073, 61420106011); 上海市科委重点资助项目(13JC1402600, 14511100100)
Estimation algorithm of sampling clock frequency offset for OOFDM system based on training sequence
Received date: 2015-04-22
Online published: 2017-02-28
研究了光正交频分复用(optical orthogonal frequency division multiplexing, OOFDM)系统中采样时钟同步问题, 提出了一种基于训练序列互相关特性的易于硬件实现的采样时钟频偏估计算法. 算法的主要思想是对接收到的训练序列与本地已知训练序列作互相关, 利用该相关值周期性变化一次产生一个采样点数差的特性, 由少量加法器和一个除法器得到采样时钟频率偏差(sampling clock frequency offset, SCFO)值. 通过在一个强度调制直接检测的光正交频分复用(intensity-modulation and direct-detection-OFDM, IMDD-OFDM)系统上的实验, 验证了该算法具有较好的准确度和抗噪性能.
张镇, 宋英雄, 张俊杰, 顿涵, 郭松霖, 薛子威 . 基于训练序列的OOFDM采样时钟频率偏差估计算法[J]. 上海大学学报(自然科学版), 2017 , 23(1) : 138 -146 . DOI: 10.3969/j.issn.1007-2861.2015.02.011
This paper studies sampling clock synchronization for optical orthogonal frequency division multiplex (OOFDM) systems, and proposes a simple sampling clock frequency offset (SCFO) estimation algorithm for hardware implementation based on crosscorrelation properties of the training sequence. The main idea is as follows. First, correlation between the received training sequence and the known training sequence is obtained, and then sampling clock frequency offset found with a few adders and one divider based on the property that an additional sampling point is introduced when the cross-correlation
value periodically changes a cycle. An optical OFDM system with intensity-modulation and direct-detection (IMDD-OFDM) is set up to show performance of the algorithm. Experimental and simulated results indicate that the algorithm has good accuracy and noise immunity.
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