Research On PPM Anti-multipath Underwater Communication System Using Frequency Hopping And Multiple Pulse

The ocean contains huge resources so that the exploration of the sea grows with each passingday with the development of society. People use underwater communication to develop themarine survey technology. It helps people on the marine resources development andutilization effectively. What’s more, underwater communication plays an important role insafeguarding national interests. This paper proposes an improved frequency hopping multiplepulse channel code based on the basic principle of pulse position code. It is intended tocombat multipath underwater and improve the quality of communication. This kind ofchannel coding method use two-dimensional encoding in time domain and frequency domain.Cross correlation coefficient between the LFM signals of different frequency bands is muchlower than the self correlation coefficient. And this principle helps the symbol design.This paper objectively analyzed the advantages of the PPM channel coding based on thefrequency hopping and multi pulse in underwater acoustic communication using thesimulation method. The simulation is divided into two parts, underwater acoustic channelmodeling and multiple pulse PPM communication system with frequency hopping. Inunderwater acoustic channel modeling, we use double search method to improve thecomputational efficiency of eigen rays. And the environment which is close to the realunderwater is used in the analysis of multiple pulse PPM communication system withfrequency hopping. Research shows that the multiple pulse PPM with frequency hoppingunderwater acoustic communication system has a strong performance in the multipath fading.The bit error rate is close to the PPM multi pulse communication in the same condition butno multipath channel.