Design And Implementation Of Underwater Wireless Communication System Receiver Based On Current Field Theory

With the more deeply exploration of oceans,underwater wireless communication plays an increasingly important role in it.Current filed communication technology gradually appears in people’s vision in recent years.Compared with other underwater communication technology,the current field communication has many advantages in short-range communication.Two receivers for underwater wireless communication system are designed and implemented in this paper.Detailed design of the circuit and associated code are given in this paper.It tests these two receivers at last.This paper can be divided into five parts:The first part is the background and development process of underwater current field communication.Current field communication is compared with other underwater communication technology in this part.It discusses the research status of underwater current field communication at home and abroad.The theory of underwater current field communication and method to improve the communication distance are introduced in the second part.OQPSK demodulation theory is described at the same time.It analyzes OQPSK modulation characteristics and describes the use of COSTAS loop in carrier synchronization.The theory of bit synchronization and frame synchronization are given with corresponding implementation method.It introduces the frame head method used to solve phase ambiguity caused by COSTAS loop at last.The third part is design of hardware circuit board.It gives the design of every modular in these two receiver.And related parameters are adjusted because of the different carrier frequency of two receivers.Detailed schematics and response parameter setting are given with detailed description.Tina and other circuit simulation software are used for the simulation of each module.It introduces the design of FPGA code and simulation with MODELSIM in the fourth part.This part analyzes the implementation method of carrier synchronization,bit synchronization,frame synchronization and serial upload modules with VHDL.It gives the simulation result with MODELSIM at last.The last part is system test.Every part of the hardware circuit board is tested with instrument.SIGNALTAP is used to test each part of software.These two receiver are tested with transmitter at last.These two current field underwater wireless communication receivers designed in this paper have three advantages: small antenna size,high stability and highly practical.It can serve as an important part of short-range underwater wireless communications in the future.