Gamma-Gamma大气湍流下超奈奎斯特光通信系统性能

Performance of Faster-than-Nyquist Optical Communication System under Gamma-Gamma Atmospheric Turbulence

利用超奈奎斯特传输技术可进一步提升现有大气光通信系统的传输速率,但是大气湍流的存在会严重影响系统的性能。针对这一问题,推导了Gamma-Gamma大气湍流信道中超奈奎斯特大气光通信系统的平均误码率和平均容量表达式。讨论了湍流强度、传输距离、加速因子等参数对系统性能的影响。蒙特卡罗仿真结果表明,超奈奎斯特传输技术可有效提高系统的平均容量,同时传输距离的增加和加速因子的减小对系统误码率及平均容量的影响较明显。在加速因子为0.75、信噪比为18 dB、弱湍流条件下,采用超奈奎斯特传输技术后系统的平均容量优于未引入该技术的系统的31%。

The transmission rate of the existing atmospheric optical communication systems can be improved using the faster-than-Nyquist transmission technology;however, atmospheric turbulence will considerably affect the system performance. Therefore, in this study, expressions are derived for obtaining the average bit error rate and average capacity of the faster-than-Nyquist atmospheric optical communication systems under a Gamma-Gamma atmospheric turbulence channel. Further, the effects of the turbulence intensity, transmission distance, and acceleration constant on the system performance are discussed. The Monte-Carlo simulation results demonstrate that the average capacity of the system can be improved using the faster-than-Nyquist transmission technology. In addition, the increasing transmission distance and decreasing acceleration constant significantly affect the bit error rate and average capacity of the system. Under the weak turbulence channel condition, the average capacity of the system using the faster-than-Nyquist transmission technology is better than 31% of the system without this technology when the acceleration constant is 0.75 and the signal-to-noise ratio is 18 dB.