In this chapter, we focus on acoustic underwater networks, which utilize acoustic communication links to communicate between the nodes. It is wellknown that RF signals do not propagate well underwater, and the optical signals [1] are useful for short distances and under clear water propagation conditions. For long distances, the Navy has utilized acoustic communication. More recently, there has...

 Acoustic signals offer a means of establishing wireless networks in shallow water regions. These networks may provide command and control for autonomous underwater vehicles, forward reporting by arrays of sensor grids, ad hoc communications links to covert forces, or positive control of unmanned, forward-deployed weapons systems. However, the capacity limitations and extreme propagation delay...

Underwater swarm robotics is an emerging topic. Compared to individual autonomous vehicles, high-capacity communication links are required between the mobile agents. In this tutorial, suitable technologies studied, with emphasis on LED-based underwater optical wireless communications. A comprehensive overview about challenges, advances, and practical aspects of employing communications provided...

A key research area in wireless transmission is underwater communications. It has a vital role in applications such as underwater sensor networks (UWSNs) and disaster detection. The underwater channel is very unique as compared to other alternatives of transmission channels. It is characterized by path loss, multipath fading, Doppler spread and ambient noise. Thus, the bit error rate (BER) is i...

While wireless communication technology today has become part of our daily life, the idea of wireless undersea communications may still seem far-fetched. However, research has been active for over a decade on designing the methods for wireless information transmission underwater. Human knowledge and understanding of the world’s oceans, which constitute the major part of our planet, rests on our...

Direct sequence spread spectrum (DSSS) techniques for low probability of intercept (LPI) and multi-user communications applications for underwater acoustic communications are investigated. Two promising receivers, a RAKE based receiver and a hypothesis-feedback equalization based architecture are considered. The performance of the proposed receiver structures are compared based on simulations a...

The past decades have seen a growing interest in underwater wireless communications researches, but this faces many challenges, specially through physical processes that cause impact in this communication technique. Despite this, underwater wireless networks seems to be a good solution for water quality monitoring in pisciculture tanks, since this service requires a lot of time and manpower. Th...

Abstract Recent research has indicated that single carrier frequency domain equalization (SC-FDE) is an attractive technology for underwater acoustic communications. Because it does not have the drawbacks of OFDM systems such as large peak-to-average ratio and the sensitivity to carrier frequency offsets. In this paper, three kinds of frequency domain equalization schemes were compared in the u...

Underwater acoustic wireless sensor networks (UAWSNs) are capable of supporting underwater missions. Due to the unique characteristics of underwater environments e.g. large attenuation and long propagation delay, the transmission range of sensor nodes in UA-WSNs is usually much shorter than that of the terrestrial counterparts, which limits communications between sensors and makes the system in...

We analyze the problem of localization algorithms for underwater sensor networks. We first characterize the underwater channel for radio communications and adjust a linear model with measurements of real transmissions. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network. In this setting, we assume low connectivity of the nodes, low data...