Survey of Acoustic Frequency Use for Underwater Acoustic Cognitive Technology

Abstract

The available underwater acoustic spectrum is limited. Therefore, it is imperative to avoid frequency interference from overlapping frequencies of underwater acoustic equipment (UAE) for the co-existence of the UAE. Cognitive technology that senses idle spectrum and actively avoids frequency interference is an efficient method to facilitate the collision-free operation of multiple UAE with overlapping frequencies. Cognitive technology is adopted to identify the frequency usage of UAE to apply cognitive technology. To this end, we investigated two principle underwater acoustic sources: UAE and marine animals. The UAE is classified into five types: underwater acoustic modem, acoustic positioning system, multi-beam echo-sounder, side-scan sonar, and sub-bottom profiler. We analyzed the parameters of the frequency band, directivity, range, and depth, which play a critical role in the design of underwater acoustic cognitive technology. Moreover, the frequency band of several marine species was also examined. The mid-frequency band from 10 40 kHz was found to be the busiest. Lastly, this study provides useful insights into the design of underwater acoustic cognitive technologies, where it is essential to avoid interference among the UAE in this mid-frequency band. Received 7 October 2021, revised 5 November 2021, accepted 16 December 2021 Corresponding author Youngchol Choi: +82-42-866-3833, ycchoi@kriso.re.kr c 2022, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.