Characterization Of Channel For Underwater Visible Light Communication Based On Monte Carlo Simulation

Underwater visible light communication(VLC) is a new technology to achieve underwater high-data-rate communication, which can effectively make up the shortcomings of traditional underwater acoustic communication, such as the long delay, low data transmission and being susceptible to the conditions.This technology shows great potential in the construction of underwater sensor network, exploration of submarine world and monitoring data.It has gradually been in hot research.In this paper, the characteristics of underwater optical communication by using the Monte Carlo method are analyzed, and realistic parameters are taken into account in experiments. A lot of research has studied the light transmission in underwater based on the exponential model. But the researches based on exponential model treat the influence of light scattering as a part of attenuation coefficient, with neglect to the spatial expansion of light scattering, and this makes errors inevitably. In this paper, we generate the light scattering angle with the scattering phase function, which is the approximated by the TTHG function based on the study of volume scattering functions. Then we obtain the impulse response of received signal of different link parameters, based on the analysis of mounts of light scattering processes with Monte Carlo method.Then the channel attenuation and received optical power of different water type, different link distance and different transmitting and receiving parameters are studied. After analysis of the source of the noise, the signal to noise ratio in different conditions is simulated.After the analysis, we draw the conclusion that the received signal power of light through scattering is-10 d B of the received power of the light directly shining into the receiver; the inter symbol interference caused by the temporal spread due to light multiple scattering is negligible in the underwater optical communication of low data-rate below 100 Mbps; besides the half emission angle of light resource,effective receiving area of the receiver have important influence on the link distance that can achieve effective communication.Finally, we analyze the performance of underwater optical MIMO communication system. On the basis of getting the channel of attenuation of each channel, we obtained the H matrix which describes the characteristics of MIMO system. Then we analyze the channel capacity of MIMO systems in different conditions and in different signal to noise ratio based on the H matrix. The result shows that MIMO systems of underwater optical communication have a significant effect on the data transmission. But the channel capacity of the system is affected by the turbidity of undersea water.