Adaptable design for long range underwater communications

We address the challenge of adaptable long-range underwater acoustic communications. Applications include defence, emergency response, environmental monitoring, and search and rescue. We have developed a communication system aiming to achieve long rage communications in the harsh conditions of the Canadian Arctic. We use low-frequency underwater acoustic waves that have the 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 concerning underwater communication conditions. We vary the interval of symbols of 4-tone Frequency-Shift Keying modulation from one design to another. This has the effect of increasing the SNR. Hence, the ability to operate in less favourable conditions. We have simulation results. Moreover, we have obtained sea trial results. The communication system had been tested in sea trials in a test facility on the east side of Vancouver Island and the Canadian Arctic.