Research On Underwater Communication System Based On LDPC Code

With the continuous development of communication technology in theory and practice,underwater communication research has also overcome one after another problems,technology is also more and more progress.The establishment of underwater communication system model is an important part of underwater communication,which involves many key technologies of hydro acoustics.These techniques have become a hotspot in many scholars’ research,including simulating underwater environment simulation of underwater acoustic channel,simulating underwater acoustic channel Model,adding multipath effects,Doppler shift,ocean noise and other practical factors.Based on these methods,how to improve the data transmission efficiency,system performance and reduce the transmission complexity and information error rate of the underwater acoustic communication system are analyzed on the basis of the underwater environment.Using different algorithms to achieve simulation and compare the advantages and disadvantages of these technical means.In this paper,we mainly study the characteristics of shallow acoustic channel,use LDPC code to the underwater acoustic channel for information transmission,and improve the underwater acoustic channel to improve the performance of underwater acoustic communication system,select the appropriate LDPC coding algorithm for data transmission,and further increase the underwater communication system’s channel bandwidth utilization and improve the reliability of data transmission.This paper first introduced the research status of the related contents of the underwater communication system,and made a theoretical study on the key technologies related to underwater acoustic communication,including the characteristics of underwater acoustic channel,the way of information coding and decoding,and the environmental noise of underwater communication system.Used computer to simulate the underwater acoustic channel,including shallow sea short distance and shallow sea long-distance channel.This paper mainly used MATLAB to model the multipath fading model,simulated the problems existing in underwater communication,and analyzed the information transmission in the underwater channel.Secondly,this paper proposes to use the normalized LMS algorithm to balance the underwater acoustic channel before simulating the underwater channel,which greatly reduces the complexity of the channel model and improves the communication rate.In the aspect of coding,LDPC codes with good anti-interference,anti-fading and anti-noise performance are selected.The basic algorithm of LDPC code compilation and the construction method are analyzed and studied.The regular LDPC coding and BF decoding,select the appropriate parameters for simulation analysis,reducing the complexity of LDPC code.Finally,the LDPC codes are applied to the underwater communication system.The advantages and disadvantages of the LDPC codes used in the underwater acoustic communication are discussed.The simulation model of the LDPC codes in different underwater acoustic channels is established.The LDPC codes are compared with the LDPC codes in different modulation methods,different underwater channels and different code length performance.In this paper,the performance of LDPC codes in different underwater acoustic channels,different code length and different modulation modes is analyzed emphatically,and the channel is improved.The coding performance of LDPC codes is simulated and the communication performance is better,which provides theoretical guidance for practical application.