Abstract:

The differential Orthogonal Frequency Division Multiplexing(OFDM) technique and mixed ex- citation linear prediction speech sounds encoding technique are combined in a system. The system could be against multi-interference effectively, it has advantages including low PAPR and high rate, also meets the requirement of underwater speech sounds communication rate. Using channel codes with different coding efficiency in the system, the relation curves of BER versus SNR were given, which show that loss of coding efficiency could improve the robustness of the system. Convolution-code was selected and com- pared with convolution-code in the differential OFDM system, and pilot-added OFDM system was also compared. The results show the feasibility and utility of the differential system. Meanwhile, the experi- ment for the differential system under different distances testifies the robustness.

Key words: aconstics, underwater acoustic communication, differential Orthogonal Frequency Division