Simulation Of Dual-mode Underwater Acoustic Communication And Its Realization On OMAPL138

The demand for exploration and development of the oceans is becoming more and more urgent,and the acoustic communication network is attracting more and more attention.As the main component of the underwater communication network,the underwater communication network needs to be laid on the sea floor for a long time.The maintenance cost is relatively high.Therefore,it is necessary to design the communication algorithm reasonably,reduce the complexity of signal resolution and prolong the working time.In this paper,the frequency hopping and OFDM-MFSK techniques based on incoherent demodulation are studied from the perspective of reducing the complexity of communication algorithms,and the dual-mode underwater acoustic communication method is transplanted based on the existing OMAPL138 hardware platform.Firstly,the theoretical research and simulation of point-to-point frequency hopping and underwater acoustic communication technology are carried out,including the problem of frequency hopping pattern selection,mutual restraint of system parameters,Doppler estimation and compensation.The underwater acoustic frequency hopping communication has good robustness,especially in the offshore channel,and the non-coherent demodulation method based on energy demodulation is low and easy to implement.Because of the low transmission rate of the frequency hopping communication system and the inability to realize the transmission of large data volume,this paper studies the OFDM-MFSK underwater acoustic communication technology,which is also based on energy demodulation,and studies the convolutional code coding,Viterbi translation The basic principle of the decoder and on the basis of the baseband and passband carried out the communication performance simulation.OFDM-MFSK communication does not need to adopt channel estimation and equalization technology,and the complexity is low.This not only ensures the high rate requirement of the whole system,but also keeps the low complexity of the non-coherent demodulation method.Finally,this paper introduces the dual-mode communication algorithm based on TI's OMAPL138 chip hardware platform.The main contents include the related peripheral drive configuration and modulation and demodulation,codec and real-time solution of waveform transmitting and signal acquisition module The algorithm can realize the realization of the dual-mode communication node,which can detect both the frequency hopping and OFDM-MFSK signals,and can support the communication network to run the ALOHA protocol.