Research On Underwater Communication System Based On Photoacoustic Heterogeneous Physical Field

Underwater communication in photoacoustic heterogeneous physical fields is a new type of air sea cross media wireless communication method.In underwater communication in photoacoustic heterogeneous physical fields,aerial targets transmit pulsed laser signals carrying information underwater,interaction between pulsed laser and water,laser induced acoustic phenomena can occur underwater.At this point,the laser signal is converted into an acoustic signal,underwater targets receive acoustic signals and recover information to achieve air to underwater cross media communication.Photoacoustic heterogeneous physical field underwater communication combines the advantages of light in the air channel and sound in the underwater channel,It has the advantages of wide communication coverage,strong operability,good information timeliness,high concealment and mobility.It has a good application scenario in the construction of the future sea,land,air and space global interconnection private network.Therefore,this paper will study the underwater communication of photoacoustic heterogeneous physical field.The main work is as follows:(1)The photoacoustic heterogeneous physical field communication channel is studied.The photoacoustic conversion efficiency under the mechanism of optical breakdown is the highest,which has good practical significance.Compared to the air optical channel,the underwater acoustic channel has a more significant impact on the communication system.(2)The photoacoustic heterogeneous physical field experiment platform was built and the photoacoustic signal was studied.The selection of laser repetition frequency will affect communication performance.The lower the repetition frequency,the slower the communication rate,but the better the signal stability and communication reliability,and the weaker the connection between repetition frequency and the main frequency of the photoacoustic signal.(3)The modulation technology of photoacoustic heterogeneous physical field communication is studied.This paper analyzes the performance of photoacoustic factors in underwater communication systems with photoacoustic heterogeneous physical fields under PPM modulation,and proposes a modulation technique called time difference modulation that can improve the underwater communication rate of photoacoustic heterogeneous physical fields.This modulation technique has a higher bandwidth utilization rate under time difference modulation compared to OOK modulation and PPM modulation at the same communication bandwidth and a single symbol modulation bit amount greater than 2.(4)The synchronization technology of photoacoustic heterogeneous physical field communication is studied.A symbol synchronization method based on edge detection is proposed by utilizing relevant synchronization techniques to achieve frame synchronization.This method can effectively improve synchronization accuracy below 5d B and achieve ideal synchronization at 5d B.(5)The underwater communication system of photoacoustic heterogeneous physical field is designed and tested.The communication system is implemented in terms of hardware and software,and communication system test conducted,the test results verify the feasibility of the designed underwater communication system of photoacoustic heterogeneous physical field.