Low Probability of Detection for Underwater Acoustic Communication: A Review

Abstract

Low probability of detection (LPD) is an extremely important characteristic of an underwater acoustic communication (UWAC) system when used for military-related applications, since the detection of a communication signal in the channel may reveal the presence of the transmitter or receiver. Furthermore, the recent advances in the understanding of the environmental effects of sound transmission in the ocean have led to a growing interest in LPD for UWAC also for civilian use. This is because systems that are designed for reliable communication at low signal power have a reduced environmental impact. In this paper, we identify the main challenges for the design of UWAC LPD systems. We describe and classify common approaches for transmission, reception, and interception of LPD signals, and we discuss their advantages and weaknesses. We also present several methods to determine the LPD capability of a system and suggest to adopt the range ratio test as a performance measure that captures the effects of signal propagation through the UWAC channel and the capabilities of the communication receiver and a signal interceptor. In light of the environmental benefits of LPD transmission and ongoing discussions about limiting the power spectral density of UWAC signals through regulations, we believe that LPD transmission is an area of growing importance for UWAC research and development. We hope that this paper serves as a motivation and a starting point for further research in this field.

Design and Analysis of an Equivalent Load Power-Stability Control Circuit for Cabled Underwater Information Networks

“…Moreover, exploring the ecosystem of the deep ocean is the key to understand the development of human civilization [1][2][3][4]. Over the last several decades, oceans have been observed with traditional shipborne and airborne mobile platforms or explored by underwater vehicles [5], anchored buoy stations, and battery-powered equipment [6]. However, these are only lateral, partial, and temporary ways to explore and research the ocean, and it is currently impossible to realize a full-scale, comprehensive, and real-time high-resolution stereoscopic observation of the ocean from the seabed to the surface [4,7,8].…”

“…CUINs have surmounted the two major difficulties of energy supply and information transmission in ocean observation, and have become the mainstream development direction of the marine environment monitoring network [6]. Observation and electrical equipment in the networks relies on a remote power supply system connected to shore-based power supply equipment to provide energy.…”

Bionic Morse Coding Mimicking Humpback Whale Song for Covert Underwater Communication

“…Innovative and novel techniques are being explored to keep information safe from intruders [1]. The demand of secretly transmitting data in underwater acoustic channels is rapidly increasing in oceanography, military and naval operations [2,3]. Mariners desire to transmit their information clandestinely to secure it from data theft and malicious attacks [4].…”

Symmetry Oriented Covert Acoustic Communication by Mimicking Humpback Whale Song

“…The information needs to be kept secret from any eavesdroppers [3], but can be decoded by the intended receiver. A variety of ways have been investigated for CUAC, which includes low SNR communication, encryption, and disguising as sea marine mammals [4,5].…”