The underwater environment can be considered a system with time-varying impulse response, causing time-dependent spectral changes to a transmitted acoustic signal. This is the result of the interaction of the signal with the water column and ocean boundaries or the presence of fast moving object scatterers in the ocean. In underwater acoustic communications using mediumto-high frequencies (0.3–...

Secure and anonymous routing is required in many underwater acoustic network applications such as marine military. However, the characteristics of underwater acoustic networks cause existing secure scheme designed for traditional terrestrial networks to be inapplicable. This article presents a secure routing design for underwater acoustic networks. First, considering the difficulty of setting a...

Nowadays, underwater wireless sensor networks (UWSNs) are known as a powerful technique for aquatic applications. UWNS has long propagation delay, limited bandwidth and higher error rates in comparison with ground based networks. Moreover, a terrestrial wireless communication uses radio waves, but underwater communication relies on acoustic waves. Similar to other wireless sensor networks, desi...

The principles of sensor networks—low-power, wireless, in-situ sensing with many inexpensive sensors—are only recently penetrating into underwater research. Acoustic communication is best suited for underwater communication, since other methods (optical and radio) attenuate very quickly. Yet acoustic propagation is five orders-ofmagnitude slower than RF, so propagation times stretch to hundreds...

Underwater sensor networks represent an important and promising field of research due to the large diversity of underwater ubiquitous applications that can be supported by these networks, e.g., systems that deliver tsunami and oil spill warnings, or monitor submarine ecosystems. Most of these monitoring and warning systems require real-time communication in wide area networks that have a low de...

This paper describes development of adaptive filter algorithm for an Underwater Acoustic Telemetry (UWAT) system for communication between the off shore underwater device (UD) and on-shore communication system. In this system, FSK modulation and de-modulation techniques are used with centre frequency of 38 KHz with baud rate of 300Hz. Adaptive filter algorithm has been developed to compensate t...

We describe an approach to decentralized control and distributed data fusion that enables a team of autonomous underwater vehicles to cooperatively and autonomously localize and track a source of acoustic noise, and we report on field experiments that demonstrate the efficacy of our approach. A principal challenge of subsea coordination is the the extremely low-bandwidth acoustic communication ...

Multicarrier techniques have made it possible to wirelessly transmit data at higher rates for underwater acoustic (UWA) communication. Several multicarrier been explored in the past wireless transmission. OFDM is known fight off inter-symbol interference due orthogonality of its subcarriers. However, time variations, suffers from intercarrier interference. As UWA channel both a and frequency va...