Research On Underwater Half-duplex Wireless Optical Communication Based On Network Protocol

With the in-depth exploration of marine resources by humans,the communication between humans and the oceans is becoming more and more frequent,and the support of high-speed underwater wireless transmission technology is urgently needed.Underwater wireless optical communication has the outstanding advantages of high speed,small size and low power consumption.It is considered as an effective means to solve the high-speed underwater short-range wireless transmission.It has attracted wide attention in recent years.In underwater two-way wireless optical communication engineering applications,the presence of backscattering can cause crosstalk in the bidirectional link,which greatly restricts communication performance.Aiming at this problem,this paper designs the optical communication system based on the half-duplex communication mode to isolate the crosstalk caused by time-separated backscattering and verifies the feasibility of the scheme.The main work and innovations of this paper include the following three aspects:(1)Based on blue LED and large area PMT,underwater half-duplex wireless optical communication hardware components are designed and developed,which can support link rate of 20Mbps;(2)Based on the network protocol,the data transmission logic in half-duplex communication is designed,which solves the software synchronization in the half-duplex mode and the clock synchronization problem in the communication process;(3)Build and complete the joint test of the system,complete the ground test experiment and the underwater test experiment respectively,realize the link transmission rate of up to 20Mbps,and the water transmission distance is 18m,which verifies the feasibility of the system scheme.