Underwater Communication Networks Research Articles

Performance investigation of a VLC-PDM based UWOC system under adverse underwater conditions with varying chlorophyll levels

Underwater Wireless Optical Communication (UWOC) has emerged as a promising solution to meet the growing demand for high-speed, reliable communication in marine environments. The limitations of traditional acoustic and radio frequency (RF) communication methods in underwater settings, such as low data rates, high latency, and susceptibility to environmental conditions, have propelled the exploration of optical communication technologies. This work introduces a Visible Light Communication (VLC)-based UWOC system employing Polarization Division Multiplexing (PDM) to enhance data transmission rates and system performance. The proposed system capitalizes on the advantages of VLC, including high bandwidth, low latency, and immunity to electromagnetic interference, to achieve efficient underwater communication. By incorporating PDM, the system effectively doubles the channel capacity without increasing the bandwidth, achieving a data transmission rate of 1Gbps per channel. The performance of the proposed system was evaluated under various underwater conditions, including freshwater, clear ocean water, coastal water, and turbid ocean water with different chlorophyll concentrations. The results demonstrated the system's ability to maintain a low Bit Error Rate (BER) across diverse marine environments, showcasing its potential for real-world applications in underwater communication networks.

Исследование алгоритмов организации сетей АНПА с использованием программной среды моделирования

Development of a network of autonomous underwater vehicles (AUV) is a complex multifactorial task. Solution of this problem requires the fulfillment of a number of stringent requirements, including, requirements for fault tolerance, efficiency of information exchanges, energy efficiency, etc. As a result, it is very important to use simulation for test proposed solutions of AUV network design. The purpose of current research is development and test a software environment for designing AUV networks. The simulation environment is implemented within the framework of an object-oriented approach in Python. The main results obtained include the established principles for implementing a software environment for simulation of AUV networks. The layout of the hardware and software for underwater communication network developed in Concern CSRI Elektropribor is the basis of the developed simulation model. The results of testing the software are presented using the example of solving the problem of ensuring the efficiency of information exchanges. The developed software environment makes it possible to increase the efficiency of AUV network development.

A 930 m/180 Gbps*User Underwater Coherent Optical Code-Division Multiple-Access Network Based on Hybrid 256-Differential Pulse Position Modulation and Weighted Modified Prime Code Sequence

Currently, there are three types of optical communication networks based on the communication channel between the transmitter and receiver: the optical fiber channel, visible light channel, and optical wireless channel networks. The last type has several advantages for underwater communication, wireless sensors, and military communication networks. However, this type of optical network suffers from weather conditions in free-space communications and attenuation owing to the scattering and absorption mechanisms for underwater communication. In this study, we present a new transceiver architecture of a coherent optical code-division multiple-access (OCDMA) system based on a hybrid M-ary differential pulse position modulation scheme and a spreading code sequence called weighted modified prime code for underwater communication to minimize channel dispersion, increase the transmission rate per second, enhance the network bit error rate (BER) performance, and improve network security. Using an OCDMA system, we can simultaneously expand the network coverage area and increase the number of users sharing the network over the same channel bandwidth. The simulation results in this study proved that the proposed system can accommodate 1310 active users and a network throughput of 180 Gbps*user over a transmission distance of 930 m without any repeater at a 10−9 BER performance, compared to the 45 Gbps*user network throughput and 100 m transmission distance reported in the literature.

Robustness of vortex wave based communications to operational variables

Orbital angular momentum (OAM) based acoustic communications are a promising method of increasing bandwidth in underwater acoustic communications networks as their unique phase patterns form an orthogonal basis set on which communications protocols may be based. The underwater acoustic environment, however, is highly complex and dynamic. These complexities make developing systems capable of long-range communications challenging. Methods for using BELLHOP’s ray tracing software to simulate the time series of vortex-wave based communications signals are presented. Additionally, this study explores the robustness of the inner product deconvolution method of decoding OAM-based communications against various operating conditions, considering both environmental and platform variations. The effects on channel cross-talk are assessed against sound speed profile uncertainty, position errors, Doppler Effect, and turbulence in the water column. These analyses shed light on the operational implementation of OAM-based communications systems.

Penegakan Hukum Terhadap Pelaku Tindak Pidana Perusakan Kabel Bawah Laut Di Wilayah Hukum Polres Tanjung Jabung Barat Berdasarkan Uu No. 36 Tahun 1999 Tentang Telekomunikasi (Studi Kasus: Putusan Nomor 36/Pid.Sus/2023/PNKlt)

Underwater cables refer to all types of cables laid on the surface of the seabed, undersea cables have now developed into a Sea Cable Communication System (SKKL) thatare interconnected and mutually supportive. Underwater communication cables are cables laid under the sea to connect telecommunications between countries. The disconnection of the underwater cable communication network also occurred in the waters of the Pengabuan River, West Tanjung Jabung Regency. In this case the Tanjung Jabung Barat Resort Police, which is the jurisdiction of the incident, received a report and quickly carried out the law enforcement process, especially since this incident was the first time this had happened in the jurisdiction of the West Tanjung Jabung Police. As a result of the disconnection of the underwater cable network, it causes electromagnetic disturbances in the form of blackouts or interrupted communication networks. The purpose of this study is to understand and analyze how law enforcement is against the perpetrators of the criminal act of destroying undersea cables in the jurisdiction of the West Tanjung Jabung Police based on Law no. 36 of 1999 concerning Telecommunications (Case Study: Decision Number 36 /Pid.Sus /2023 /PN KLT), to understand and analyze the factors that become obstacles, and to understand and analyze the efforts made in overcoming existing obstacles. The research method used is empirical juridical. The results showed that in this case the Captain of the Ship, TB. DABO 103 is an element that is proven to have caused the interruption of the underwater fiber optic network in the waters of the Pengabuan Estuary, due to its negligence resulting in a violation of the provisions of Article 322 Jo Article 216 paragraph (1) of the Law of the Republic of Indonesia Number 17 of 2008 concerning Shipping whichreads"The skipper who carriesout repair activities, trial sailing, loading transfer activities at the port pool, delays, and loading and unloading of dangerous goods without the approval of the Syahbandar as referred to in Article 216 paragraph (1) shall be punished with imprisonment for a maximum of 6 (six) months or a fine 100,000,000.00 (one hundred million rupiah) at the most." For his negligence, the defendant was sentenced to imprisonment for 5 (five) months, because he was proven to have violated the provisions of Article 322 Jo Article 216 paragraph (1) of the Law of the Republic of Indonesia Number 17 of 2008 concerning Shipping, namely carrying out repair activities without the approval of Syahbandar. From the results of the research carried out, the suggestions given are that it is necessary to make ongoing appeals to captains to complete navigation tools in the form of BPI Pushidrosal Maps (Indonesian Seafarers' News) and the latest Marine Maps which serve to explain the latest situations and conditions in the waters and also which can explain the existence of the position of items under the sea including undersea cables so that similar incidents do not happen again.

Energy harvesting techniques for sustainable underwater wireless communication networks: A review

The emergence of various underwater wireless communication systems has been on the rise due to increasing human activities in the marine environment. In underwater wireless communication networks (UWCNs), several communication devices, such as sensors and autonomous underwater vehicles (AUV) are interconnected to expand communication coverage, monitoring, information gathering, and surveillance. These devices operate on batteries, making their replacement and recharging difficult. Consequently, sustaining the operational lifetime of UWCNs is deemed a major challenge. This leads to the development of various energy harvesting (EH) techniques to perpetuate the power supply to underwater devices. In this paper, we present a review of various energy sources and EH techniques applicable to UWCNs. To achieve this, we classify the energy sources into various categories in order to establish the peculiarities of each source and the type of harvester applicable to each category. Based on this classification, we present discussions on various contributions of articles related to applications of EH techniques in UWCNs. In addition to various insights gained from the presented papers, we establish that energy harvesters based on triboelectric effect, piezoelectric effect, sediment microbial fuel cell, acoustic, and optical power transfer are suitable for low-power (milliwatt-order) consuming devices such as sensors. Also, for devices with high power consumption requirement, such as AUV, solar and inductive power transfer-based harvesters should be employed. Furthermore, we identify several technical challenges that should be taken into consideration during the planning and system design phases. Finally, we highlight open research areas that could further improve the EH and communication processes in UWCNs.

Toward Immersive Underwater Cloud-Enabled Networks: Prospects and Challenges

Underwater engineering significantly increases the liveability and sustainability of our planet's ecosystems. Enhancing the connectivity of ocean-based engineering systems and ensuring its digital resilience is, therefore, indispensable for reaping the benefits of underwater engineering systems. To this end, this work proposes augmenting underwater engineering systems with cloud connectivity platforms as a paradigm shift for upscaling underwater communication networks and applications. The envisioned underwater cloud-assisted network (UCAN) provides joint underwater computing, processing, communication, and acquisition while benefitting from the cooling features of the aquatic environment. We first survey the literature on conventional underwater wireless communication networks. We then describe the prospects for UCANs and advocate the deployment of UCANs for sustainable connectivity. Next, we explore the opportunities stemming from the deployment of UCANs—e.g., resource management, natural cooling, and underwater intelligence. Finally, we highlight the challenges and open issues arising from such a futuristic cloud-enabled underwater communication network—e.g., channel modeling, characterizing achievable-rate, quality-of-service retrofitting, and preserving marine biodiversity.

Priority based energy efficient hybrid cluster routing protocol for underwater wireless sensor network

<p class="Affiliation"><span lang="EN-US">A little change in the environment that goes unnoticed in an underwater communication network might lead to calamity. A little alteration in the environment must also be adequately analyzed in order to deal with a potential crisis. A priority-based routing protocol is required to ensure that the vital data perceived by the sensor about the environment changes. The priority-based routing system guarantees that vital data packets are delivered at a quicker pace to the destination or base station for further processing. In this work, we present a priority-based routing protocol based on the energy efficient hybrid cluster routing protocol (EEHRCP) algorithm. The suggested approach keeps two distinct queues for lower and higher priority data packets. In order to ensure that these packets get at their destination without any information loss and at a quicker rate, all of the crucial sensed data is passed through a higher priority queue. Test findings show that the suggested technique increases throughput, delivery percentage, and reduces latency for the crucial data packets.</span></p>

Modelling of an Efficient Electromagnetic Method for Underwater Wireless Communication

This paper investigates the characteristics of brief-term variety in wireless communications in the underwater environment. Nowadays, they are extensively used in experimental research related to underwater communication networks and channel estimations for an efficient link. From the first perspective, the main research exploration enquiry depends upon increasing the distance and frequency range. In this research work, an electric current method focusing on RF wave propagation is chosen. This technique in the seawater is produced by a couple of electrodes sensed by two receipt electrodes. The method can be an option as the waves show less effective refraction and reflection effecting in deep and shallow water.

Reliable Data Transmission in Underwater Wireless Sensor Networks Using a Cluster-Based Routing Protocol Endorsed by Member Nodes

Considering Underwater Wireless Sensor Networks (UWSNs) have limited power resources (low bandwidth, long propagation delays, and non-rechargeable batteries), it is critical that they develop solutions to reduce power usage. Clustering is one solution because it not only saves energy consumption but also improves scalability and data integrity. The design of UWSNs is vital to the development of clustering algorithms. The limited energy of sensor nodes, narrow transmission bandwidth, and unpredictable topology of mobile Underwater Acoustic Wireless Sensor Networks (UAWSNs) make it challenging to build an effective and dependable underwater communication network. Despite its success in data dependability, the acoustic underwater communication channel consumes the greatest energy at a node. Recharging and replacing a submerged node’s battery could be prohibitively expensive. We propose a network architecture called Member Nodes Supported Cluster-Based Routing Protocol (MNS-CBRP) to achieve consistent information transfer speeds by using the network’s member nodes. As a result, we use clusters, which are produced by dividing the network’s space into many minute circular sections. Following that, a Cluster Head (CH) node is chosen for each circle. Despite the fact that the source nodes are randomly spread, all of the cluster heads are linked to the circle’s focal point. It is the responsibility of the MNS-CBRP source nodes to communicate the discovered information to the CH. The discovered data will then be sent to the CH that follows it, and so on, until all data packets have been transferred to the surface sinks. We tested our techniques thoroughly using QualNet Simulator to determine their viability.

Overview of Underwater Wireless Communication Routing Protocols

Underwater wireless communication is the use of acoustic, optical, electromagnetic waves and other technologies to send information underwater. This article reviews existing routing protocols for underwater wireless communication network design. Particular attention is paid to their performance in terms of communication efficiency, data rate, latency, and packet loss. The different types of routing protocols are discussed in detail, highlighting their respective strengths and weaknesses. This article also covers issues related to security and scalability and how they affect the performance of the entire network. Finally, this paper discusses the future trend of underwater routing protocols and proposes promising research directions.

The Pacific futures of subsea data centers

This article considers current research and development efforts around the creation of subsea data centers. Such experiments (e.g. Microsoft’s Project Natick) aim to identify new techniques for maximizing data center efficiency by harnessing the cooling effects of the surrounding ocean. To date, subsea data center experiments have had more success in Atlantic contexts, but the history of information and communication technologies (ICTs) and the sea suggests that subsea data centers will no doubt have Pacific futures. Situating this discussion within the unique cultural and environmental landscapes of the Pacific islands, particularly Hawaiʻi, we anticipate anxieties that stem from historical patterns of project development that lack consideration of cultural impact. We argue that a pre-conversation about subsea data centers is necessary given the extant data infrastructures in Hawaiʻi already corroding or within the margins of risk for obsolescence and decay. Finally, as islands and island nations, especially, are often targets for colonization as vital hubs in underwater information and communication networks, the article examines the tensions in such subsea experiments between impact and impermanence, between global and local, and between corporate and community.

On the UOWC Performance Under Location Uncertainty

More often than not, currents due to gravity, wind friction, and heterogeneous water density cause frequent drifts of the end-users to random locations creating transmission problems in an underwater optical wireless communication (UOWC) network. The location uncertainty effect on the overall network performance in harsh environments, including submarine ones, is an appealing issue that needs to be adequately addressed in the existing technical literature. The present work takes account of a vertical UOWC link where a fixed transmitter at the sea surface illuminates towards the seabed following a Lambertian pattern. In this way, a randomly placed receiver inside a spherical cone is served, and the problem is treated with three-dimensional stochastic geometry methods. In the sequel, the complete statistical behavior of the random distributions of the channel gain and the instantaneous electrical signal-to-noise ratio is estimated. Moreover, some critical network performance metrics, including the outage probability and the bit-error rate for intensity modulation/direct detection with on-off keying and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</i> -ary pulse position modulation, are derived, whereas indicative numerical results are illustrated adequately through a series of appropriate figures.

Experimental evaluation of the impact of physical beam misalignment on the performance of an underwater wireless optical communication network utilizing machine learning

Underwater wireless optical communication systems have garnered significant interest due to advantages in speed and security over radio-frequency and acoustic underwater transmission. One example utilizes Laguerre–Gaussian beams carrying orbital angular momentum to increase bit transfer rate by spatially multiplexing information into an alphabet of symbols, sized 2N, where N is the number of bits encoded in each symbol. This system uses a convolutional neural network (CNN) to demultiplex the information, which has been shown to be capable of high levels of accuracy even in turbid environments or in the presence of significant optical turbulence. However, it has been observed that CNNs struggle when shown images affected by physical environmental effects (different levels of turbulence, optical magnification, beam misalignment) that were not present in the training set. In this paper we further investigate physical beam misalignment under two experimental conditions, quiescent and strong optical turbulence. Physical beam misalignment is defined as a translation of the beam at the receiver. Our optically turbulent environment is characterized using the scintillation of a Gaussian beam, and is estimated to have a refractive index structure constant value of ∼10−11m−2/3. We use two alphabet sizes, of 16 and 256 symbols, and demonstrate classification of received images in a combination of scenarios with adequate success (>90% accuracy) when training and testing under the same conditions, and using a pre-trained CNN, AlexNet. However, when training and testing under physically misaligned conditions, we demonstrate an issue with impractical rates of classification, at 5%–50%. Our investigation provides CNN classification at significantly higher levels of complexity than previously seen, both in terms of experimental turbulence strength and number of classifiable symbols (alphabet size), and clearly demonstrates the importance of carefully designed experiments to aid the machine learning training process for communication systems.

Lifetime Maximization in Underwater Wireless Communication Networks

The rise in demand for underwater wireless communication networks (UWCN) has been driven by the emergence of new applications including unmanned underwater vehicles, deep-sea exploration, maritime and underwater archaeology research, and diver communications. For various applications, underwater network lifetime must be long, since unlike terrestrial sensor networks, it is a major job to change/recharge node batteries in underwater environments. In this paper, we introduce a solution where critical nodes in a UWCN are periodically recharged by small renewable energy sources. Further, a caching mechanism is introduced to relieve critical nodes of heavy workload when their residual energies run low. By leveraging these two techniques of energy replenishment and content-caching, the network lifetime extension challenge is formulated as an optimization problem. The results indicate that our proposed solution offers up to 45% longer UWCN lifetime compared to existing solutions.

DEVELOPMENT OF AUTONOMOUS UNDERWATER VEHICLE (AUV) BASED ON ROBOTIC OPERATING SYSTEM FOR FOLLOWING UNDERWATER CABLE

In addition to satellites, the Marine Cable Communication Channel (SKKL) which is located under the sea is also one of the backbones of the communication network to connect from one island to another. However, there are often irresponsible parties who damage or commit acts of vandalism. This action resulted in the disruption of the communication process on the submarine cable network. So, it is necessary to periodically check the condition of the underwater communication network cables. Regular checking of underwater cables is very risky, so we propose an underwater robot to handle it. This paper presents the development of Autonomous Underwater Vehicle (AUV) based on Robotic Operating System (ROS) for Following Underwater Cable to monitor the condition of the cables automatically. The AUV is equipped with a camera, Nvidia Jetson Nano, Arduino, Flight Controller, ESC, and brushless DC motors that used to assist the tracking process on the cable. The camera is used as the main visual sensor. Visual image processing methods are carried out using thresholding and contours detection methods, then the obtained data are processed to drive the motors on the AUV so that they can move on the direction of the cable. The experiment results show that the object detection method can be used under conditions with light intensity more than 25 lux. It works optimally at speeds of 0.27 m/s to 0.42 m/s. In the horizontal motion control test, the overshoot parameter value is ±60%, rise time is 2s, settling time is 16s, and steady state error is ±20%. The AUV can track on a straight and winding path of 2 meters with a bright light intensity of ±493 lux, a dim light of ±107 lux and a dark light intensity of ±25 lux with the help of an LED beam with a light intensity of ±773 lux. The percentage of success of scoping experiments on a straight track and a winding track with three trials is 75%. This performance shows that the developed AUV works well to follow underwater cable.

Device models and technologies of data transmission and processing in the internet of things networks

The subject of research is the analysis and definition of the information model of devices, the choice of technologies and protocols for data collection and analysis, routing protocols for the Internet of Things (IoT) networks. The purpose of the article is to create an information model of IoT devices, to define technologies and protocols for data transmission and processing and routing in Internet of Things systems. Building an information model of an IoT device includes identifying data sources and their formats, creating a model and data structure, and analyzing them using tools such as: Eclipse Vorto ThingBoard, Ubodots IoT, Node-Red-UI, freeboard.io . An example of a description of a model of microclimate control devices using the Eclipse Vorto toolkit is given. Two main data processing technologies from IoT devices are considered: IBM Watson IoT, Cisco IWF with examples of their application. Radio frequency, infrared, optical and galvanic technologies for interaction between data collection and data transmission devices in IoT networks with examples of their use are discussed. The areas of application of three main IoT network protocols are considered: MQTT (large corporate networks), CoAP (limited networks on the Internet), Bluetooth Low Energy (local networks without the Internet with a small amount of data).Wi-Fi WebSockets, ZigBee, LoRA, Simple RF, XMPP, RFID, NFC can be used as additional protocols for networks. The features of using routing protocols in IoT networks are discussed: RPL (low power consumption), cognitive RPL (for intelligent networks), CARP (for underwater communication networks), E-CARP (for data reuse).

Outage probability analysis of a vertical underwater wireless optical link subject to oceanic turbulence and pointing errors

The reliability of an underwater wireless optical communication (UWOC) network is seriously impacted by beam misalignment between transmitters (Txs) and receivers (Rxs). Also, the performance of UWOC systems can be affected by oceanic turbulence-induced fading due to fluctuations in the water refractive index as a result of variations in the pressure, water temperature, and salinity. In this work, we investigate the performance analysis of a vertical UWOC link subject to oceanic turbulence and pointing errors and further investigate the appropriate selection of link parameters to optimize link performance. This study is based on an accurate mathematical framework for link modeling while taking into account realistic Tx/Rx and channel parameters under different turbulence and beam misalignment conditions. We provide an analytical expression for calculating the link outage probability, whose accuracy is validated through numerical simulations. Last, the necessity of optimal Tx/Rx parameter selection to minimize the link outage is demonstrated. A laser beam is considered at the Tx, as well as an ultra-sensitive photodetector (silicon photo-multiplier) at the Rx to enable working at relatively long link ranges. The presented results give valuable insight into the practical aspects of deployment of UWOC networks.

AUV-Aided Hybrid Data Collection Scheme Based on Value of Information for Internet of Underwater Things

The current Internet of Underwater Things (IoUT) for marine observations and emergency responses suffers from two critical issues: 1) energy efficient and 2) timely data collection. Autonomous underwater vehicles (AUVs), serving as tools for collecting and forwarding distributed data, can deal with the unbalanced power consumption in a traditional multihop underwater communication network. However, the low speed of the AUV has not been able to guarantee the timeliness of delay-sensitive data. In this article, we introduce a hybrid data collection scheme (HDCS), taking both real-time data collection and energy efficiency (EE) issues into consideration. All sensor nodes (SNs) are first clustered based on their locations in the network. We develop an analytic expression to describe the attenuation of Value of Information (VoI), involving the relationship between the importance degree and timeliness; initial VoI could be measured by historical data. The emergency can be recognized by the presented criterion, and the transmission mode of cluster heads (CHs) in the same layer is judged by CHs themselves according to VoI. The selected CHs shall transmit the urgent data via multihop routing to avoid over attenuation of VoI. The normal data are collected by AUVs visiting all remaining CHs, and the shortest trajectory is achieved by addressing a variation of the classic traveling salesman problem (TSP). Our simulation experiments show that this mechanism can effectively increase long-term VoI while significantly improving EE.

Reinforcement Learning for Distributed Energy Efficiency Optimization in Underwater Acoustic Communication Networks

To solve the problems of poor quality of service and low energy efficiency of nodes in underwater multinode communication networks, a distributed power allocation algorithm based on reinforcement learning is proposed. The transmitter with reinforcement learning capability can select the power level autonomously to achieve the goal of getting higher user experience quality with lower power consumption. Firstly, we propose a distributed power optimization model based on the Markov decision process. Secondly, we further give a reward function suitable for multiobjective optimization. Finally, we present a distributed power allocation algorithm based on Q-learning and use it as an adaptive mechanism to enable each transmitter in the network to adjust the transmit power according to its own environment. The simulation results show that the proposed algorithm not only increases the total channel capacity of the system but also improves the energy efficiency of each transmitter.