由于水下信道的多径效应、时变效应, 水下无线电通信速率及信噪比均十分低, 在实际的水下通信应用场景, 如水下传感器网络, 需要同时获取多个信号源的码流信号, 提出一种基于CMOS摄像头的水下可见光多输入多输出(MIMO)通信系统。系统采样曼切斯特编码以用于不同距离的信号源的时钟信号恢复, 同时提出了多个信号源识别及光强拟合的方法并研究了在水下环境中波特率对信号波形畸变的影响。实验结果表明: 在尺寸为4 m×3 m×3 m的试验池中, 对LED阵列进行优化布局后, 本系统可实现21 kb/s的水下通信, 可适用于诸如水下传感器网络的短距离、少信息量的数据交换场合。

Due to the multipath effect and time-varying effect of underwater channel, the underwater radio communication rate and signal-to-noise ratio are very low. In the actual underwater communication application scenario such as underwater sensor network, it is necessary to obtain the code stream signals of multiple signal sources at the same time. An underwater visible multi input multi output(MIMO) communication system based on CMOS camera is proposed. The system samples Manchester code to recover the clock signal of different distance signal sources. At the same time, the method of multiple signal sources identification and light intensity fitting is proposed. The influence of baud rate on the signal waveform distortion in underwater environment is explored. The experimental results show that the system can achieve 21 kb/s underwater communication after the LED array is optimally arranged in a 4 m×3 m×3 m test cell. It can be used in short distance and small information data exchange occasions such as underwater sensor network.