Development and Testing of an OFDM Physical Layer for the DESERT Simulator

Falleni, Sara; Saha, Dola; Haque, Imtiaz; Melodia, Tommaso; Basagni, Stefano

doi:10.23919/oceans44145.2021.9738729

Cited by 3 publications

(4 citation statements)

References 9 publications

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“…In the last twenty years, a vast literature has focused on underwater acoustic sensor networks and communication systems, but lately more and more solutions have focused on the adaptivity of the communication system and networking protocols based on the changing environment [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Design method for long-term evaluation of underwater acoustic communications and networks in a Norwegian fjord environment

Tomasi,

Øyerhamn,

Otnes

2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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Fjords often have difficult underwater acoustic propagation properties, such as the acoustic shadow zones created by highly dynamic bathymetry and thermocline/halocline. In addition, shallow-water coastal underwater acoustic horizontal communications are characterized by several reflections at the boundaries creating complex and timevarying multipath channel structures. We present an iterative simulation and experiment-based method for designing and evaluating an underwater acoustic communication system and the network layers built on it. First, we present the sound speed profiles collected throughout the year in the fjord at Austevoll in western Norway. Then we discuss the setup used to collect acoustic channel impulse responses in the frequency band 55-65 kHz in the same geographical area. We then provide the results of numerical modeling for the acoustic propagation and present the methodology that we plan to implement in the next few years for a long-term evaluation and improvement of acoustic sensor networks in fjord environments.

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Section: Introductionmentioning

confidence: 99%

Design method for long-term evaluation of underwater acoustic communications and networks in a Norwegian fjord environment

Tomasi,

Øyerhamn,

Otnes

2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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“…A desirable characteristic of these modems (when using OFDM) is being able to receive multiple packets transmitted on different subcarriers at the same time. The experimental evaluation offered in this paper leverages DESERT modules developed after the SeaNET modem design [110].…”

Section: Network Scenariomentioning

confidence: 99%

“…In this paper, we only show the comparison with CSMA, as in the investigated scenarios this MAC protocol outperforms all other single-carrier protocols. The DESERT implementation of RAMAC relies on OFDM Physical Layer and OFDM-based Interference modules of our design [110].…”

Section: Performance Evaluationmentioning

confidence: 99%

“…RAMAC operations are based on a simple channel reservation mechanism that is also used to communicate which subcarriers should be used for data transmission on a per-packet basis. We implement the protocol in the open-source underwater simulator DESERT[75,106], which we chose for its widespread use, and for which we developed a SEANet-based OFDM physical layer module[110]. We evaluate the performance of RAMAC against a baseline single carrier protocol, challenging them in various scenarios.…”

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confidence: 99%

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OFDM-based medium access control protocols for the next generation of underwater wireless networks

Falleni

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Despite covering 71% of Earth's surface, 80% of the oceans remain unexplored and unmapped. Even if extremely important, ocean exploration is just one of many applications that could benefit from networks of connected underwater devices capable of sensing the environment and communicating with each other wirelessly. Other applications that could benefit from underwater wireless networks include disaster prevention, oil and gas pipeline monitoring, aquaculture, habitat restoration, and national security.Networks of underwater wireless devices typically use acoustic waves for communicating as that is the sole technology capable of propagating for long distances in water. However, these networks encounter several obstacles, such as slow propagation speed, the Doppler effect, reflections, and constantly changing channel characteristics.The basic building block of underwater acoustic wireless networks is the underwater acoustic wireless modem. Over time, attempts have been made to create faster and more reliable underwater acoustic modems, such as those manufactured by Teledyne Benthos and Evologics. Nevertheless, the acoustic modems currently available in the market suffer from two primary issues: slow data rates and an inflexible software and hardware architecture which impedes new protocol and standard development.Intending to advance the field of underwater wireless networks, i.e., realizing networks that are faster than the state of the art and that can adapt to the ever-changing conditions of the marine environment, this work investigates the field of Medium Access Control protocols in underwater networks. Specifically, it focuses on MAC protocols that rely on Orthogonal Frequency-Division Multiplexing (OFDM) physical layers, the physical layer technique that is also used in Wi-Fi and LTE. To investigate OFDM-based MAC layers in the real world and at scale, we follow two parallel xii paths: i) for the real-world MAC layer testing we first design, develop, and test the SEANet modem, a software-defined acoustic platform. We then design, implement, and test OFDM-based MAC protocols using a small network of SEANet modems. ii) To test the efficacy of OFDM-based MAC layer protocols in large networks we design implement and test several OFDM-based MAC Protocols on multi-hop networks using the DESERT simulator. The MAC protocols tested on the DESERT simulator leverage the OFDM technology at the physical layer as well as reinforcement learning.Experiments carried out in the simulated environment and the real network of SEANet modems confirm that OFDM-based MAC Protocols achieve higher data rates with respect to the state of the art and allow the network to be smarter and more reliable, especially when selective interference is present. The addition of reinforcement learning to the OFDM-based MAC protocols produces networks that are adaptable with minimal human contribution.xiii

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A Reservation-based Adaptive MAC Protocol for OFDM Physical Layers in Underwater Networks

Falleni

Melodia

Basagni

2023

2023 International Conference on Computing, Networking and Communications (ICNC)

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Development and Testing of an OFDM Physical Layer for the DESERT Simulator

Cited by 3 publications

References 9 publications

Design method for long-term evaluation of underwater acoustic communications and networks in a Norwegian fjord environment

Design method for long-term evaluation of underwater acoustic communications and networks in a Norwegian fjord environment

OFDM-based medium access control protocols for the next generation of underwater wireless networks

A Reservation-based Adaptive MAC Protocol for OFDM Physical Layers in Underwater Networks

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