Software Modems for Underwater Sensor Networks

OCEANS'10 IEEE SYDNEY, 2010

OCEANS 2006, 2006

This paper describes the design and successful development of an acoustic modem for potential use in underwater ecological sensor networks. The presentation includes theoretical study, design and development of both software and hardware, laboratory experiments, and the documentation and analysis of field-test results.

Underwater wireless sensor Networks (UWSN) provide a variety of attractive working fields such as aquaculture, offshore exploitation and underwater monitoring. These applications require spreading an important number of nodes which requires to develop simple, reliable and energy efficient modem architectures to reduce the economical cost, the developing time and the power consumption, still being efficient and robust. This paper overviews research efforts of our research team conducted during the last year to develop an acoustic communication system for UWSN. To address the cost and power consumption limitations, the design and the implementation of a low cost and energy efficient underwater modem and a new acoustic-triggered wake-up system were researched. The result of combining both researches resulted in the development of ITACA-S1000 modem, a solution with a very low power consumption and with a very advanced remote wake-up system. Since this modem was the first coherent FSK so...

Lecture Notes in Computer Science

Applications of underwater sensor networks involve environmental monitoring, disaster prevention, and resource detection. As the importance of these applications has recently grown, underwater sensor networks made up of sensor nodes have to be further investigated. However, little research has been performed to develop an underwater sensor node with communication functionality. In an underwater environment, typical RF-based communication is not appropriate because of two facts. One fact is that radio waves require large antennae and high transmission power. The other fact is that the Berkeley Mica 2 Motes have been reported to have a transmission range of 120cm underwater. Consequently, we have concluded that underwater communication has to use an acoustic or ultrasonic wave rather than a radio wave. The objective of our work is to develop an acoustic modem for underwater communication, where we have to consider an energy-aware acoustic modem. This is because the battery can not easily be recharged underwater as well as in a terrestrial environment. As a consequence, an acoustic modem has to be designed with low-power. In this paper, we describe our implementation of an energy-aware acoustic modem and its performance in underwater experiments.

OCEANS'11 MTS/IEEE KONA, 2011

In this paper, we present a networked acoustic modem system (NAMS) by integrating a high-speed OFDM modem and a comprehensive underwater network protocol stack for underwater applications. This integrated system allows different underwater network protocols to run on top of the OFDM modem platform and can provide high-speed, reliable and efficient communications in underwater environments.

OCEANS 2021: San Diego – Porto, 2021

The need for wireless underwater communication systems exists due to the constraints that tethered wired communication systems place on underwater equipment, and the extensive time and effort required to retrieve information from remote underwater installations. With current available commercial underwater acoustic modem systems only offering low data rates for use mainly in control signals and sensor telemetry data transfer from deep depths and over large distances, there exists a need for a wireless system capable of handling large, high-speed data transfers over shorter distances. Being able to transmit data at a high transmission rate in turn requires higher frequencies and a broader system bandwidth. With the development of advanced wideband ultrasonic transducer technology within the Council for Scientific and Industrial Research (CSIR), the application of such transducers for broadband underwater acoustic data communication for high data rates and reliable transmission has been researched and investigated over the past few years. A prototype broadband acoustic underwater data communication (BAUDC) system has been developed, with the intended end goal of being able to perform large data transfers, such as sonar images, from an unmanned underwater vehicle (UUV) to a surface ship, surface buoy or submarine at a sufficiently high data rate to allow the data to be received in near real-time. The prototype BAUDC system is currently still under development, but it has so far produced excellent results. During testing of the system in the CSIR’s sonar testing tank, a set of transducers having a bandwidth of around 280 kHz achieved data rates over 200 kbps with a bit-error-ratio (BER) of 0, meaning no bit-errors occurred. The prototype system has also been tested in a real shallow water environment inside a harbor, with a communication distance of 200m successfully achieved.

Underwater channel data transmission is one oj telecommunications most difJicult problems. One way to optimise the transmission may be by adapting transmission techniques used in telecommunications modems. The articles presents two ITU-T standards: V.34 and G.992.1, known as ADSL. The possibilities and limitations ojthese techniques jor underwater communication systems are discussed. The ADSI standard using the DMT modulation seems to be the best.

2016

In order to achieve underwater acoustic high datarate and real time communications, it is essential to implement a system that operates both at high and wideband frequencies using digital modulations. Therefore, to reduce the time and cost of developing acoustic communications an emulator of a physical layer model was implemented, allowing to test in real time the performance of digital modulations. The model was composed of an emitter transducer, a hydrophone and the subaquatic medium and was integrated in a Field Programmable Gate Array (FPGA) in order to emulate the physical layer in the acoustic modem testing. The emitter transducer and the hydrophone models were designed to meet real prototype characteristics. The system prototype was implemented in order to compare the experimental trials results with those obtained in emulator, emulating the transmission of acoustic signals, using different types of digital modulations. The system was tested using Binary Phase-Shift Keying (BPSK), Binary Frequency Shift keying (BFSK) and Binary Amplitude Shift Keying (BASK) modulations with a 1 MHz carrier frequency resulting in a data rate of 125 kbps. It was verified that the implemented model represents a suitable approximation to the real subaquatic communication channel, allowing the evaluation of digital acoustic communications.

Applied Sciences, 2022

The aim of the paper is to present a simplified implementation of quadrature phase shift keying (QPSK) based underwater communication system. The presented solution addresses the problem of developing inexpensive, compact ultrasound modems able to be mounted on underwater robots. Simplifications introduced into the modulation and demodulation of QPSK signals do not disturb any parameter of the data link. The paper indicates that it is possible to realize modulation and demodulation on a simple microcontroller. Many hints are given on how to use hardware blocks embedded in a microcontroller, such as ADC, DMA, timers, etc. Experiments performed with the prototype modems allow to reach 4 kbps data rate on a distance of about 18 m.

Buletin Pos dan Telekomunikasi, 2020

Underwater acoustic communication is a technology that uses sound or acoustic waves and water as its propagation medium. This technology has been used in various fields, such as underwater wireless sensor networks, underwater monitoring system, and surveillance systems. An acoustic modem is required to facilitate communication between nodes. In this paper, an underwater acoustic modem using Frequency Shift Keying (FSK) modulation has been designed. This modulation is widely used because of its reliability and simple design. FSK modem was designed using M=2 level or known as Binary FSK (BFSK) with 40 kHz mark frequency and 43 kHz space frequency. This study tested data packets sending and its error rate against the distance variation. Testing for 70-bit data resulted in 1% error at 100 cm distance and 37% error at 170 cm distance. When compared with the previous testing at 1200 bps which resulted in 0% and 35% error, it can be seen that error at 1200 bps is better than at 2400 bps, but the data transmission was better at 2400 bps. Addition to the number of bits sent and distance has an influence on the error value, i.e. the greater the distance and the amount of data sent, the greater the error value.