Study On Underwater Wireless Optical Communication System With Bidirection And High-speed

With the proposal of the Marine Power Strategy,the ocean research has attracted widespread attention from the academic community and industry,as well as the ocean developmentandutilization.Underwatercommunicationbecomesanimportant information-bearing means for ocean activities.Although underwater acoustic communication has a long transmission distance and has been well-established,it has a small bandwidth,a low rate,a long time delay and poor confidentiality.At present,the highest communication rate of acoustic with high-order modulation is less than^kbps,it is difficult to satisfy the high-speed transmission of images,videos and other services.There is an urgent need for a communication method with high speed,large bandwidth,high energy efficiency,and good confidentiality.Therefore,underwater wireless optical communication has become a research hotspot.This thesis focuses on channel modeling,high-speed communication system designing and bidirection communication experiments of underwater wireless optical communication.The main work is as follows.?1?Modeled the underwater wireless optical channel based on the Monte Carlo,and simulated the relationship between the transmission distance and path loss of the four types of seawater in deep seawater,clear seawater,coastal water and port water,it shows that the more turbitiy of seawater,the shorter of distance.And simulated the relationship between the off-axis angle of the receiving plane and the received optical power,it shows that the received optical power will decrease badly when a small off-axis angle of the receiving plane.?2?Designed and developed the circuit modules of underwater wireless optical transmitters and receivers with speed of 100 Mbps.And builed communication system to perform system performance tests under the conditions of different simulating types of seawater channels.The transimission distance can reach out 16m at 100Mbps,when it is a clear water channel,and the BER is 2.0×10^-4(less than the FEC threshold of 3.8×10^-3).?3?Designed and developed an pair of Ethernet conversion interface modules to establish a bidirection underwater wireless optical communication system which can realize the transmission of Ethernet real-time services,such as voice calls,large data files,and real-time video,with a maximum speed of 100 Mbps.