Real-time low-complexity diversity combining algorithm for free space coherent optical communication systems over atmospheric turbulence channel

被引:1
作者
Xu, Kejia [1 ]
Song, Jingwei [1 ]
Li, Yan [1 ]
Chen, Junjie [1 ]
Qiu, Jifang [1 ]
Hong, Xiaobin [1 ]
Guo, Hongxiang [1 ]
Yang, Zhisheng [1 ]
Wu, Jian [1 ]
机构
[1] Beijing Univ Posts & Telecommun, State Key Lab Informat Photon & Opt Commun, Beijing 100876, Peoples R China
关键词
PERFORMANCE; SIGNAL; PHASE;
D O I
10.1364/OE.505931
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
A novel diversity combining scheme, in conjunction with the complex-valued decision-directed least mean square (CV-DD-LMS) algorithm, is evaluated, and a real-time experimental validation is presented. This proposed scheme employs the CV-DD-LMS algorithm to concurrently perform beam combination and carrier phase recovery (CPR), thereby effectively reducing the overall complexity of digital signal processing. Furthermore, in the numerical simulation, under a low signal-to-noise ratio (SNR), a scheme utilizing the CV-DD-LMS algorithm effectively avoids cycle slips (CS) and outperforms schemes employing independent CPR modules. We experimentally validate this novel scheme by implementing it on an FPGA in a real-time 2.5Gb/s QPSK diversity-receiving system with three inputs. The back-to-back sensitivity is assessed using static received optical power, while the dynamic performance is evaluated by employing variable optical attenuators (VOAs) to simulate a power fluctuation at a frequency of 100kHz. The result proves that the implementation of the CV-DD-LMS algorithm yields stable performance while effectively reducing computational complexity.
引用
收藏
页码:40705 / 40716
页数:12
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