大气相干激光通信的中断概率和信道容量研究

Investigation of outage probability and channel capacity foratmospheric coherent laser communication

针对大气相干激光通信常受到信道衰减、大气湍流和指向误差等效应影响的问题,分析在这些复合效应下的大气信道的衰落分布模型,求出中断概率和信道容量的闭合解。研究得出,一方面,虽然指向误差恶化了相干激光通信系统的中断性能和信道容量,但是通过将指向精度控制在ξ=1.4量级可明显降低其影响;另一方面,虽然高阶数的自适应光学补偿能更好地抑制大气湍流引入的光相位畸变,但是较低阶数(J=3)的自适应光学补偿可明显改善中断概率和信道容量。为了实现高可靠、大容量的大气相干激光通信,在系统设计时需联合考虑低阶自适应光学补偿和高精度光束指向、跟踪。

In the domain of atmospheric coherent laser communication,several factors such as channel loss,atmospheric turbulence,and pointing errors continually affect its performance.The fading distribution model of atmospheric channel under these composite effects is analyzed,and the closed-form solution of the outage probability and channel capacity is solved.The research concludes that,on the one hand,although the pointing error deteriorates the outage performance and channel capacity of the coherent laser communication system,it can be significantly reduced by controlling the pointing accuracy to the order of magnitude ofξ=1.4;on the other hand,although high-order adaptive optical compensation can better suppress the optical phase distortion introduced by atmospheric turbulence,low-order(J=3)adaptive optical compensation can significantly improve the outage probability and channel capacity.Therefore,in order to realize high-availability and high-capacity atmospheric coherent laser communication,low-order adaptive optical compensation and high-precision beam pointing and tracking should be jointly considered in system design.