弱湍流下逆向调制光通信直流偏置光正交频分复用系统性能分析  

Performance Analysis of DCO-OFDM in Modulated Retro-reflector Optical Communication over Weak Turbulence

作　　者：唐芳 徐智勇 汪井源 赵继勇 李建华 TANG Fang;XU Zhiyong;WANG Jingyuan;ZHAO Jiyong;LI Jianhua(Institute of Communications Engineering, Army Engineering University, Nanjing 210007, Jiangsu, China)

机构地区：[1]陆军工程大学通信工程学院,江苏南京210007

出　　处：《兵工学报》2020年第7期1368-1374,共7页Acta Armamentarii

基　　金：江苏省光通信工程与技术研究中心计划项目(ZXF20170101)。

摘　　要：针对现有微机电系统逆向调制器调制速率低、线性区域有限的问题,根据双限幅直流偏置光正交频分复用(DCO-OFDM)的特点,通过DCO-OFDM提高逆向调制光通信的传输速率。将双限幅引起的非线性失真建模为限幅噪声,推导有效信噪比函数;研究地—地和空—空特殊通信条件下,逆向调制光通信中双限幅DCO-OFDM在弱湍流中的理论平均误码率公式,并采用蒙特卡洛法进行仿真,分析对称限幅时直流偏置对性能的影响。结果表明:在较大的光功率下,有效信噪比随着直流偏置的增大,先增大、后减小;较小的直流偏置会造成严重的限幅噪声,限制有效信噪比随光功率变化;该结果对通信链路的设计优化有一定的参考意义。The retro-reflect modulator of micro-electro-mechanical system has low modulation rate and limited linear region.To improve the transmission rate effectively,a symmetry clipped DC-biased optical orthogonal frequency division multiplexing(DCO-OFDM)is proposed in the light of DCO-OFDM characteristic.The nonlinear distortion caused by double clipping is modeled as clipping noise,and the effective signal-to-noise ratio function is derived.the theoretical average bit error rate of the double clipping DCO-OFDM of modulated retro-reflector optical communication system in weak turbulence under special communication conditions like ground-ground and air-air is studied and simulated using Monte Carlo method,and the effect of direct current(DC)bias on the performance of symmetric clipping is analyzed.The simulated results show that the effective signal-to-noise ratio increases first and then decreases as the DC bias increases at better optical power.Small DC bias will cause severe clipping noise,thus limiting the change of effective signal-to-noise ratio with optical power.

关 键 词：光通信 逆向调制 弱湍流 直流偏置光频分复用 信噪比 限幅 平均误码率 

分 类 号：TN929.12[电子电信—通信与信息系统]