Research On Underwater Data Transmission Technology Based On 3D Magnetic Induction Communication

With the frequent human exploration activities of the ocean,the demand for underwater communication technology is also more diverse,and underwater wireless communication technologies are in a period of vigorous development.Traditional underwater wireless communication technologies include underwater acoustic communication,optical communication,electromagnetic communication,etc.,these technologies have their own specific application scenarios,but there are also some shortcomings.As a new underwater wireless communication technology,underwater magnetic induction communication has the advantages of covert communication and cross-medium transmission,so it has good prospects in underwater pipeline monitoring,water quality monitoring,and even the military field.This paper focuses on underwater magnetic induction communication technology,the communication network is constructed using magnetic induction communication,and the relay communication technology is used to realize network communication of multiple nodes.In this paper,the architecture of the underwater magnetic induction communication network is proposed,the channel model of three-dimensional magnetic induction communications is analyzed according to the architecture,and the path loss of magnetic induction communication is analyzed.According to the Bio-Savart theorem and Faraday’s law of electromagnetic induction,the distribution of the magnetic fields generated by a magnetic dipole in the water medium is explained,and the conversion process between the electrical and magnetic signals is analyzed,thus the channel model of three-dimensional orthogonal coil conditions is derived.Secondly,the underwater node based on magnetic induction communication is developed,and an embedded system hardware and software design scheme is proposed.ATA5276 RF transmitter chip is used to realize signal transmission,and the AS3933 low-frequency wake-up receiver chip is used to realize channel reception.OOK modulation and demodulation modes is adopted.The embedded software uses Free RTOS embedded real-time operating system to realize multiple task scheduling,memory management,interface driver,queue management and sleep control,etc.A magnetic induction communication node with an integrated transceiver function is successfully developed,which lays a foundation for the construction of an underwater magnetic induction communication network.This paper proposes an underwater chained network MAC protocol based on magnetic induction communication,LM-MAC,which generate different level values for each node according to the topology location,and each node controls the data forwarding rules according to the level value.Each node is set with four state machines: receiving,sending,listening,and sleeping,and the state transition follows to different working conditions.The OPNET simulation platform is used to build a single-link and a dual-link network topology.Simulation results show that LM-MAC protocol can reduce the network communication load,improve the transmission delay,the successful delivery rates of data packets and other aspects,so it can be better applied to the underwater magnetic induction communication networks.Finally,this paper has performed the test and verification of the entire system.The influences of antenna shape and size on communication signals are analyzed.The test results of point-to-point data transmission and relay data transmissions show that the scheme in this paper have great application value and research significance.