提出了一种简单、低复杂度、鲁棒性强的光正交频分复用(optical orthogonal frequency division multiplexing, OOFDM) 符号同步技术, 并予以实验验证. 算法的主要思想是在OFDM 符号的第0 子载波上加载编码的直流(direct current, DC)信号, 达到在接收端进行OFDM 帧同步和符号同步的目的. 由于该技术利用了本就闲置的第0 子载波, 不会额外损耗系统的带宽, 因此, 适用于OFDM 无源光网络(OFDM-passive optical network, OFDM-PON)系统. 在20 km标准单模光纤通信系统中, 运用该同步算法实现了2.667 Gbit/s的实时数据传输. 该技术还提供了在物理层增加网络安全机制的功能, 实现了点到点和点到多点的OOFDM 网络的符号同步.
A simple, low cost and robust scheme for optical orthogonal frequency division multiplexing (OOFDM) symbol synchronization is proposed and experimentally tested. The main idea is to load a direct current (DC) signal on a special subcarrier to achieve OFDM symbol synchronization at the receiver.
This techniqueis applicable to OFDM-PON (OFDM-passive optical network) system without additional bandwidth as the first zero subcarrier does not have any signal loaded originally. Using the proposed scheme, a real-time optical OFDM signal transmission at 2.667 Gbit/s over 20 km standard single-mode fiber is achieved. This scheme also offers an additional network security mechanism on the physical layer. Most importantly, it provides online real-time symbol synchronization for point-to-point and point-to-multipoint OOFDM network.
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