[Figure: Underwater Acoustic Communication, *WHOI.edu]
The Shallow-water Acoustic Variability Experiment 2015 (SAVEX15) is a joint underwater communication measurement campaign led by University of California San Diego and Korea Research Institute of Ships & Ocean Engineering (KRISO). The measurement will be conducted in shallow water (100m deep) in the Northern East Sea, ~100km southwest of Jeju Island, South Korea, over the period 14-29 May, 2015. The goal of SAVEX15 is to obtain acoustic and environmental data appropriate for studying the couple of oceanography, acoustics, and underwater communications in the Northern East Sea.
The AiSLab aided the KRISO in designing measurement scenarios and generating transmit signals for several promising technologies, which are cutting-edge state-of-the-arts even in the ground communication, such as orthogonal frequency division multiple-access (OFDMA), multi-directional relaying, multi-user MIMO (MU-MIMO), and generalized FDMA (GFDMA).
The application of underwater communication ranges from surveillance to resource mining, e.g., storing liquid carbon dioxide, mining methane hydrate, underwater monitoring (military defense, tsunami, earthquake), and etc [Figure]. The design of underwater communication, however, is challenging compared to the ground communication due to highly limited bandwidth (sonar radio), long distances but slow propagation, multi-hop relay network, significant time delay, time-varying frequency offset/Doppler shifts, and so on. Therefore, a careful consideration of these difficulties should be taken in designing transceivers. From this measurement campaign, the AiSLab and KRISO will look into the feasibility of the aforementioned techniques, which are carefully tailored for the underwater environment, and will pursue possible performance improvement.