为改善自由空间光通信(FSO)系统中传统判决门限技术的不足,降低连续波参照光辅助检测技术中参考光不携带任何信息给系统带来的高成本损耗, 提出了一种基于已判决信号的量化电压获得当前码元判决门限的自适应判决门限技术(ADT),提取信号中的直流分量(DC)作为连续波参考光来估计大气湍流信道的 波动特性。结果表明在误码率为10－3的条件下,自适应判决门限和直流提取技术具有更低的功率损耗,可显著提高FSO通信系统的性能。

In order to improve the shortcomings of traditional decision threshold technology in free space optical communication (FSO) system and reduce high cost loss caused by that reference light do not carry any information in continuous wave reference light assisted detection technology, an adaptive decision threshold (ADT) technique is proposed that the current code decision threshold is obtained based on the quantized voltage of judged signal previously. The direct current (DC) component in extracted signal is used as continuous wave (CW) reference light to estimate the fluctuating characteristics of atmospheric turbulence channel. Results show that under the condition of bit error rate of 10－3, the adaptive decision threshold and DC extraction technology have lower power loss, which can significantly improve the performance of FSO communication systems.