Underwater Wireless Video Transmission Using Acoustic Ofdm

The feasibility of underwater wireless video transmission using an acoustic multicarrier system for applications such as deep-sea supervisory control and inspection is discussed and proved. Such a system is of interest over short distance links, with short delays and high available bandwidth, as near real time imagery can be transmitted to monitor targeted underwater spots. This work includes three parts: (1) underwater channel study to determine necessary power levels and frequency allocation, (2) video compression to reduce the amount of data to be transmitted through the channel, and (3) OFDM modulation to achieve high bit rates over the underwater link. Experimental testing was conducted at the MIT Sailing Pavilion premises, in the Charles River, Boston. The results demonstrate the usefulness of the coupled MPEG-4 compression and OFDM modulation, reaching bit rates on the order of 90 kbps in a 115 kHz acoustic band over a 200-meter link under a variety of channel conditions.