基于PIN的水下可见光双向语音通信试验研究

Experimental Research on Underwater Visible Light Two-way Voice Communication based on PIN

针对水中射频通信系统通信距离严重受限和声学通信系统传输速率低等问题,可见光通信(VLC)系统为水下中远距离高速无线通信提供了一种解决办法。文章利用样本水质测试对水下短距离信道模型进行了估计,提出了一种短距离光路介质的衰减系数测试方法,并且开发了一种水下VLC系统。该系统根据发光二极管(LED)的伏安特性设计直流偏置电路,对其进行了频谱响应分析。在水槽中进行了蓝色465 nm和白色光源的水下全双工音频实验。实验结果表明,在发送额定光功率为1 W,接收端采用S6968的硅本征半导体(PIN)光电探测器,系统能够在样本水介质(衰减系数c=0.2067 m^(-1))中进行全双工通信,两种光源通信距离均超过了5 m。通过对接收端信号功率谱估计分析、信噪比测试以及扬声器的直观演示,验证了该实验系统语音通信性能,为后续水下VLC多种业务传输系统的开发提供了参考。

Aiming at the problems of limited communication distance and low transmission rate of underwater radio frequency communication system,Visible Light Communication(VLC)system provides a solution for underwater medium and long distance high-speed wireless communication.In this paper,the underwater short-range channel model is estimated by using the sample water quality test.A test method of attenuation coefficient of short-range optical medium is proposed,and an underwater VLC system is developed.The direct-current bias circuit is designed according to the volt ampere characteristics of Light Emitting Diode(LED),and its spectrum response is analyzed.The underwater full duplex audio experiment with blue 465 nm and white light source is carried out in a water tank.The experimental results show that when the rated optical power is 1 W,the receiving end adopts S6968 silicon Positive Intrinsic Negative(PIN)photodetector,and the system can carry out full duplex communication in the sample water(denoted attenuation coefficient c=0.2067 m^(-1)).The communication distance between the two light sources is more than 5m.The speech communication performance of the experimental system is verified through the analysis of the power spectrum estimation of the receiving signal,the signal-to-noise ratio test and the visual demonstration of the loudspeaker.The experimental results provide a guidance for the development of underwater VLC multi-service transmission system.