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A Real-Time Coded OFDM Acoustic Modem in Very Shallow Underwater Communications

In this paper, we describe the design and implementation of a high-rate modem for use in very-shallow water communications. The modem employs an orthogonal-frequency-division-multiplexing (OFDM) scheme with a powerful forward error-correcting code (FEC) -turbo block code. Bit error rate (BER) measurements obtained from coastal sea trials showed that this modem is capable of delivering good error rate performance for information rates of up to nearly 10 kbits/s at transmission distances below 1700 m.