Underwater Optical and Acoustic Communications: Research and Challenges

A special issue of Electronics (ISSN 2079-9292). This special issue belongs to the section "Microwave and Wireless Communications".

Deadline for manuscript submissions: closed (15 April 2023) | Viewed by 7853

Special Issue Editors


E-Mail Website
Guest Editor
Department of Information, Electrical and Telecommunication Engineering (DIET), Sapienza University of Rome, 00185 Rome, Italy
Interests: Internet of Things; LoRa; underwater acoustic communications; visibli light communications; Li-Fi; underwater optical communications

E-Mail Website
Guest Editor
Department of Information Engineering, University of Padova, Via Gradenigo 6/a, 35131 Padova, Italy
Interests: underwater acoustic; optical networks; underwater multimodal communications
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Department of Electronic Engineering, University of York, Heslington, York YO10 5DD, UK
Interests: underwater acoustic communications; underwater networks; network protocols; internet of underwater things
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Department of Electronic Engineering, University of York, Heslington, York YO10 5DD, UK
Interests: wireless communications; underwater networks; medium access control; routing; cognitive radio; wireless sensor and ad hoc networks; satellite systems; queuing theory; mobile communication systems; traffic modelling
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Communication technologies have advanced quickly in recent decades, improving our knowledge and exploration of the underwater world. The employment of sensors, AUVs, gliders and robots for both military and civilian activities has led to the development of what has been recently called the Internet of Underwater Things, that is, an infrastructure to support connectivity in maritime and underwater environments. In this regard, due to the peculiar characteristics of the underwater medium, acoustic communications represent an effective solution for data transmission, proving a convenient trade-off between link performance and coverage. Furthermore, the study and implementation of optical systems for delay and bandwidth-sensitive services represent topical challenges. In general, the choice of the most suitable communication technology is tied to the capability of meeting the performance requirements of the considered application. Therefore, in the future of large underwater networks and systems, it is expected for acoustics and optics to be employed in a hybrid fashion.

This Special Issue aims to collect high-quality research papers on underwater wireless communications and networking systems, based on acoustic and optical technology. The topics of interests include, but are not limited to, the following:

  • Acoustic and optical channel modeling, estimation and prediction;
  • Modulation, coding and detection techniques;
  • Signal processing for channel equalization and interference mitigation;
  • Multiple-Input Multiple-Output systems;
  • Optical and acoustic transceiver design;
  • Multiple access and routing protocols;
  • Hybrid optical/acoustic networks;
  • Internet of Underwater Things;
  • Experimental results from field trials;
  • Applications and case studies about underwater optical/acoustic communications.

Dr. Andrea Petroni
Dr. Filippo Campagnaro
Dr. Nils Morozs
Prof. Dr. Paul Mitchell
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Electronics is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (4 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

21 pages, 1181 KiB  
Article
On the Effect of Channel Knowledge in Underwater Acoustic Communications: Estimation, Prediction and Protocol
by Andrea Petroni, Gaetano Scarano, Roberto Cusani and Mauro Biagi
Electronics 2023, 12(7), 1552; https://doi.org/10.3390/electronics12071552 - 25 Mar 2023
Cited by 4 | Viewed by 1261
Abstract
Underwater acoustic communications are limited by the following channel impairments: time variability, narrow bandwidth, multipath, frequency selective fading and the Doppler effect. Orthogonal Frequency Division Modulation (OFDM) is recognized as an effective solution to such impairments, especially when optimally designed according to the [...] Read more.
Underwater acoustic communications are limited by the following channel impairments: time variability, narrow bandwidth, multipath, frequency selective fading and the Doppler effect. Orthogonal Frequency Division Modulation (OFDM) is recognized as an effective solution to such impairments, especially when optimally designed according to the propagation conditions. On the other hand, OFDM implementation requires accurate channel knowledge atboth transmitter and receiver sides. Long propagation delay may lead to outdated channel information. In this work, we present an adaptive OFDM scheme where channel state information is predicted through a Kalman-like filter so as to optimize communication parameters, including the cyclic prefix length. This mechanism aims to mitigate the variability of channel delay spread. This is cast in a protocol where channel estimation/prediction are jointly considered, so as to allow efficiency. The performance obtained through extensive simulations using real channels and interference show the effectiveness of the proposed scheme, both in terms of rate and reliability, at the expense of an increasing complexity. However, this solution is significantly preferable to the conventional mechanism, where channel estimation is performed only at the receiver, with channel coefficients sent back to the transmit node by means of frequent overhead signaling. Full article
Show Figures

Figure 1

15 pages, 930 KiB  
Article
Modeling Acoustic Channel Variability in Underwater Network Simulators from Real Field Experiment Data
by Filippo Campagnaro, Nicola Toffolo and Michele Zorzi
Electronics 2022, 11(14), 2262; https://doi.org/10.3390/electronics11142262 - 20 Jul 2022
Cited by 6 | Viewed by 1395
Abstract
The underwater acoustic channel is remarkably dependent on the considered scenario and the environmental conditions. In fact, channel impairments differ significantly in shallow water with respect to deep water, and the presence of external factors such as snapping shrimps, bubbles, rain, or ships [...] Read more.
The underwater acoustic channel is remarkably dependent on the considered scenario and the environmental conditions. In fact, channel impairments differ significantly in shallow water with respect to deep water, and the presence of external factors such as snapping shrimps, bubbles, rain, or ships passing nearby, changes of temperature, and wind strength can change drastically the link quality in different seasons and even during the same day. Legacy mathematical models that consider these factors exist, but are either not very accurate, like the Urick model, or very computationally demanding, like the Bellhop ray tracer. Deterministic models based on lookup tables (LUTs) of sea trial measurements are widely used by the research community to simulate the acoustic channel in order to verify the functionalities of a network in certain water conditions before the actual deployment. These LUTs can characterize the link quality by observing, for instance, the average packet error rate or even a time varying packet error rate computed within a certain time window. While this procedure characterizes well the acoustic channel, the obtained simulation results are limited to a single channel realization, making it hard to fully evaluate the acoustic network in different conditions. In this paper, we discuss the development of a statistical channel model based on the analysis of real field experiment data, and compare its performance with the other channel models available in the DESERT Underwater network simulator. Full article
Show Figures

Figure 1

17 pages, 7541 KiB  
Article
High-Reliability Underwater Acoustic Communication Using an M-ary Cyclic Spread Spectrum
by HyungIn Ra, Changhyun Youn and Kiman Kim
Electronics 2022, 11(11), 1698; https://doi.org/10.3390/electronics11111698 - 26 May 2022
Viewed by 1346
Abstract
Multipath propagation, frequency selective fading, low-propagation velocity, and narrow bandwidth are all characteristics of underwater acoustic channels. Doppler shifts and diffusions can occur as a result of the low transmission speed of an acoustic signal, which can be caused by the movement of [...] Read more.
Multipath propagation, frequency selective fading, low-propagation velocity, and narrow bandwidth are all characteristics of underwater acoustic channels. Doppler shifts and diffusions can occur as a result of the low transmission speed of an acoustic signal, which can be caused by the movement of ocean currents or the transceiver. Furthermore, frequency selective fading and excessive noise interference can disrupt underwater acoustic communication on a continual basis. Because of its high anti-interference ability and high confidentiality, spread spectrum technology is commonly adopted in underwater acoustic communications. Although the direct sequence spread spectrum method has a low data rate, it is advantageous in a multipath propagation channel environment or an environment with a low signal-to-noise ratio (SNR). This advantage is suitable for long-distance transmission or LPD (Low Probability of Detection) communication, and the direct sequence spread spectrum method is applied. In this paper, we propose a highly reliable M-ary cyclic spread spectrum technique by superimposing the M-ary spread spectrum, an extension of the direct sequence spread spectrum technique, and cyclic shift keying. Furthermore, by estimating the Doppler frequency using M-ary spread spectrum codes and performing synchronization correction of the ensuing symbol based on the estimation results, higher performance can be attained. Simulations and experiments showed that the M-ary cyclic spread spectrum method can reduce Doppler estimation and synchronization error accumulation while maintaining a high data rate. Furthermore, the MCSS method had a lower bit error rate than the standard spread spectrum method. Full article
Show Figures

Figure 1

25 pages, 4415 KiB  
Article
Ultra-Low-Cost and Ultra-Low-Power, Miniature Acoustic Modems Using Multipath Tolerant Spread-Spectrum Techniques
by Benjamin Sherlock, Nils Morozs, Jeffrey Neasham and Paul Mitchell
Electronics 2022, 11(9), 1446; https://doi.org/10.3390/electronics11091446 - 29 Apr 2022
Cited by 10 | Viewed by 2836
Abstract
To enable long-term, large-scale, dense underwater sensor networks or Internet of Underwater Things (IoUT) this research investigates new novel waveforms and experimental prototypes for robust communications on ultra-low-cost and ultra-low-power, miniature acoustic modems. Spread-spectrum M-ary orthogonal signalling (MOS) is used with symbols constructed [...] Read more.
To enable long-term, large-scale, dense underwater sensor networks or Internet of Underwater Things (IoUT) this research investigates new novel waveforms and experimental prototypes for robust communications on ultra-low-cost and ultra-low-power, miniature acoustic modems. Spread-spectrum M-ary orthogonal signalling (MOS) is used with symbols constructed from subsequences of long pseudorandom codes. This decorrelates multipath signals, even when the time-spread spans many symbols, so they present as random noise. A highly cost-engineered and miniaturised prototype acoustic modem implementation was created, for the 24 kHz–32 kHz band, with low receive power consumption (12.5 mW) and transmit power of <1 W. Simulations show that the modulation scheme achieves 640 bit/s at −4.5 dB with AWGN or the equivalent level of multipath energy. Experimental validation of the hardware shows successful point-to-point communication at ranges of >3 km in lakes and >2 km in the sea including severe multipath. In lake testing of a 7-node, multi-hop, sensor network with TDA-MAC protocol, packet delivery was near 100% for all nodes. Trials of acoustic sensor nodes in the North Sea achieved 99.5% data delivery over a 3-month period and a wide range of sea conditions. Modulation and hardware have proven reliable in a variety of underwater environments. Competitive range and throughput with low cost and power are attractive for large-scale and long-term battery-operated networks. This research has delivered a viable and affordable communication technology for future IoUT applications. Full article
Show Figures

Figure 1

Back to TopTop