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Characteristics of an underwater acoustic channel, which hydro-acoustic modems of the S2C technology can measure and provide to upper layer protocols, were used for evaluation of several important communication metrics and so for evaluation of the modem performance under the actual channel conditions. Particularly, these channel characteristics were used for assessment of the delivery success related...
Underwater networks that are designed to carry high-priority data at a relatively high traffic load should employ network protocols that emphasize low delay and adequate reliability at the expense of energy. ICRP (Information-Carrying based Routing Protocol), originally proposed by Wei Liang et al. [1] in 2007, is a routing protocol that obtain unicast routing paths by sending data payload as broadcast...
SeaModem is a low-cost underwater acoustic modem developed by AppliCon, a spin-off of the University of Calabria, for shallow water communications. In its default configuration, it operates in the 25–35 KHz frequency range and offers a wide range of selectable features including selectable 2-4-8 FSK modulation tones, error detection and correction algorithms via CRC and Viterbi, selectable power transmission...
In the framework of a bilateral Netherlands-Norway defense research cooperation (2014–2017) between The Netherlands Defence Materiel Organisation (DMO NL) and Forsvarets forskningsinstitutt (FFI NO), it has been shown that a compact general-purpose processor board developed for smartphones can be successfully used for real-time underwater communications using a state-of-the-art spread-spectrum modulation...
This paper deals with underwater acoustic communication, and especially details an innovative approach for off the shelves existing modems performances evaluation. The originality is to be able to predict the operational performances of existing acoustic modems in a real complex situation, without sea trials.
In this paper, we present a performance evaluation of two underwater network protocols, named GUWMANET and Dflood. The protocols were tested at sea during the final demonstration of the EDA project Robust Acoustic Communication in Underwater Networks (RACUN). The project started in 2010 with the goal to develop and demonstrate the capabilities of an underwater ad-hoc acoustic network. The trial took...
This paper presents a high-level overview of NEMO, an implementation of a communications research software workspace with special focus on application scenarios involving underwater (e.g. acoustic), and other maritime communications methods. The NEMO is an organic result of marine autonomy and communications experimentation, basically being composed of reconfigurable modules and services that interact...
In this paper, we introduce a newly developed autonomous buoy system that enables remote monitoring of an AUV. The buoy system has a dynamic positioning function and can track the target AUV. Using an acoustic data link and a radio data link, the buoy can relay the messages between the AUV and the surface monitoring system of the AUV. The first sea trial was successfully performed in October 2014.
The Deep Gen project aims at defining a generator that powers the typical mooring of instruments used for data acquisition purpose in both the deep and the shallow water environment. The generator itself is named Deep Gen. The Deep Gen exploits the marine currents to produce electrical power. Thus, instead of using only a fixed energy storage (batteries) to power the underwater instruments, here the...
Communication and positioning protocols for underwater acoustic sensor networks are widely covered in the scientific papers during the last decade and partly implemented in a few proprietary and open-source networking frameworks. The different protocols to be combined in a stack running on an acoustic modems' hardware and thus to solve various tasks of practical interest. This paper presents a novel...
This paper presents the design, implementation, and in-field experimentation of a “bilingual” underwater acoustic modem with multi-hop networking capabilities. The designed system supports the use of the JANUS physical coding scheme and of a proprietary one. JANUS is an open, simple and robust digital coding technology currently in process to become a NATO standard. The Applicon SeaModem has been...
Delay-Tolerant Networking (DTN) technology enables the nodes of an underwater acoustic network to communicate under conditions of frequent link disruptions and in networks topologies, in which end-to-end connections may never be available. Our implementation was based on the DTN2 open-source project, which represents a reference implementation of the DTN protocols and is designed as an experimental...
This paper proposes an algorithm for real-time clock synchronisation in underwater acoustic networks. The algorithm models modem clocks as linear functions and embeds the data necessary for the clock synchronisation procedure as time stamps that can be communicated in the payload of later messages and only when necessary, hence limiting the communication overhead. The proposed solution takes explicitly...
MBARI biological oceanographers make increasing use of mobile autonomous sensor platforms to observe dynamic phenomena, and require near real-time data in order to focus resources on rapidly evolving areas of interest. We have implemented a Wave Glider-based payload called Hot Spot that creates a disruption-tolerant communications network between shore and at-sea autonomous platforms. The Hot Spot...
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