研究了中强大气湍流条件下基于零判决门限差分探测(DDTZ)的自由空间光(FSO)通信系统误码率性能。在两束传输光完全相关和完全不相关的情况下, 推导了DDTZ FSO通信系统和具有最佳阈值的差分探测系统的平均误码率的计算表达式。仿真结果表明: DDTZ不存在传统固定判决门限单端探测(SDTF)中存在的差错平底问题; 两个接收信号的相关性对DDTZ误码率没有影响; DDTZ误码率性能虽不及最优差分探测, 但明显优于SDTF, 因此在可实现性和误码率性能方面, DDTZ更具实际应用价值。

Bit error rate performance of free space optical (FSO) communication systems based on differential detection with zero decision threshold (DDTZ) under moderate and strong atmospheric turbulence is investigated. Computational expressions of average bit error rate of the DDTZ FSO communication system and the differential detection system with optimal threshold are respectively derived when the two transmission lights are completely correlated or uncorrelated. Simulation results show that the problem of the error floor which is presented in single detection with fixed threshold (SDTF) dose not exist in DDTZ. The correlation of two receive signals has no effect on bit error rate of DDTZ. The bit error rate performance of DDTZ is worse than that of optimal differential detection, but better than that of SDTF. Therefore, considering of realizability and bit error rate performance, the DDTZ has more practical application value.