Frame Design for Adaptability in Long-Range Underwater Communication

The problem addressed in this paper is adaptable long range underwater acoustic communications. We use low frequency underwater acoustic waves that have potential for long range communications. Underwater propagation conditions can vary considerably. We define protocol elements for adaptable underwater communications. They comprise six frame formats with a wide range of robustness with respect to the underwater communication conditions. We vary the interval of symbols of 4-tone Frequency-Shift Keying modulation from one format to another. This has the effect of increasing the SNR. Hence, the ability to operate in less favorable conditions. The performance of our design is evaluated through simulation.