一种水下光通信中基于先验模型的预均衡方法

由于海水的散射特性,光在水下传输时会产生码间串扰(ISI)问题,传输环境较差时尤为严重。为解决该问题,文章将预均衡技术应用于基于直流偏置光正交频分复用(DCO-OFDM)调制的水下光通信系统中,并针对水下光的传输特性提出了一种基于先验信息的预均衡方法。在浑浊海港海水环境下与传统均衡算法进行了性能对比。仿真结果表明,在信噪比(SNR)较差的情况下,采用所提方法能够有效降低水下光通信系统的ISI,降低了误码可能性,提高了信道估计的可靠性。相比于最小二乘(LS)后均衡算法,误码率能下降约3.56 dB,相比于LS预均衡算法,误码率能下降约3.00 dB,相较于最小均方误差(MMSE)和最小均方(LMS)后均衡算法,误码率下降约1.85 dB。

A Pre-equalization Method based on Prior Model in Underwater Optical Communication

Due to seawater scattering characteristics,Inter-Symbol Interference(ISI)will occur in underwater transmission,especially in poor transmission environment.In order to solve this problem,pre-equalization technology is applied to underwater optical communication system based on Direct Current Offset Orthogonal Frequency Division Multiplexing(DCO-OFDM)modulation,and a pre-equalization method based on prior information is proposed.The performance of Turbid Harbor seawater channel is compared with that of traditional equalization algorithm.The simulation results show that the ISI in underwater optical communication system can be effectively reduced,as well as the Bit Error Rate(BER).The reliability of channel estimation can be improved under the condition of poor Signal Noise Ratio(SNR).Compared with the Least Squares(LS)post-equalization,LS pre-equalization and Mini-mental State Examination(MMSE)algorithms,the BER can be reduced by~3.56,~3.00 and~1.85 dB,respectively.