A method for providing digital communication over an acoustic channel is disclosed. The method includes dividing an operating frequency band of the acoustic channel into multiple adjacent non-overlapping subbands of an equal bandwidth, selecting subbands based on a symbol to be transmitted, generating a signal with linear frequency modulation in each of the selected subbands, combining the signals with linear frequency modulation, and transmitting the combined signals to the acoustic channel through an acoustic system, wherein slopes of linear frequency modulation for the signals with linear frequency modulation are equal.