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水下可见光通信(UVLC)是实现高速宽带信息传输的有效方案,但由于受到信道中吸收、散射和湍流的不利影响而面临着许多困难.针对水下湍流信道中多径和衰落带来的影响,提出了一种光正交频分复用(O-OFDM)等增益合并的分集方案,根据广义的朗伯定律得到信道增益,通过对数正态分布模拟信号衰落.采用蒙特卡洛方法对正交幅度调制(QAM)的非对称削波光正交频分复用(ACO-OFDM)和直流偏置光正交频分复用(DCO-OFDM)两种分集系统进行建模仿真,分析高斯信道和弱湍流信道下系统的误比特率,探讨不同分集数目和闪烁系数情况下的分集增益.研究结果验证了分集是降低湍流影响的有效手段,有利于改善水下信息传输性能,为弱湍流信道下正交频分复用可见光通信系统的设计、预测和评估提供参考.“,”Underwater visible light communication (UVLC) is an attractive solution to achieve high-speed and large-data transmission but challenging due to the impairments induced by absorption,scattering and turbulence.To combat effects of multipath and fading for the UVLC system over turbulence channels,optical orthogonal frequency division multiplexing (O-OFDM) schemes with the transceiver spatial diversity were proposed,which employed equal gain combining (EGC) at the receiver side.Underwater path loss was calculated by a generalized Lambertian formula,and the fading induced by weak turbulence was modelled as a lognormal-distribution random variable.Based on the channel model and Monte Carlo (MC) simulation,the bit error ratio (BER) performance for quadratureamplitude modulation (QAM) asymmetrically clipped optical OFDM (ACO-OFDM) and DC-biased optical OFDM (DCO-OFDM) systems in the channel with and without turbulence was evaluated.Furthermore,the diversity gain was estimated for different diversity orders and scintillation indexes.The results demonstrate that the diversity scheme with EGC is an effective measure to reduce the effect of turbulence and could be useful for designing,predicting,and evaluating the performance of O-OFDM UVLC system in a weak oceanic turbulence condition.