Underwater Acoustic Wireless Sensor Networks Research Articles

Statement of Removal

A randomly fluctuated vortex-induced vibration (VIV) affects the localization of moving targets in an underwater acoustic wireless sensor network (UAWSN) to cause an offset time and time synchronization error which disturbs the localization of the non-cooperative moving target. Definition 2.1, theorem 2.2 has been introduced in the present work to describe the genesis and consequences of the VIV effect in UAWSN. An elliptic localization introduces the direct and indirect path measurements of the moving target. The standard CRLB parameter quantifies the VIV effect. The compensation of vortex-induced vibrations (CVV) algorithm is proposed to quantify the degradation of localization performance and to estimate the position of the moving target. The theoretical measurements of position error, velocity error with respect to the variation of noise, number of receiver sensors, and probability of line of sight (LOS) errors are compared to the standard methods. The proposed CVV algorithm improves the localization performance by 32.24% and reduces 34.36% of position errors, and 37.46% of velocity errors up to 600 meters. It can be useful for the sub-aquatic internet of underwater things.

A Systematic Analysis, Outstanding Challenges, and Future Prospects for Routing Protocols and Machine Learning Algorithms in Underwater Wireless Acoustic Sensor Networks

Water has covered a wide part of the earth’s surface. Oceans and other water bodies contain significant natural and environmental resources as well as aquatic life. Due to humans’ hazardous and unsuitable underwater (UW) settings, these are generally undiscovered and unknown. As a result of its widespread utility in fields as diverse as oceanography, ecology, seismology, and oceanography, underwater wireless sensor networks (UWSNs) have emerged as a cutting-edge area of study. Despite their usefulness, the performance of the network is hampered by factors including excessive propagation delay, a changing network architecture, a lack of bandwidth, and a battery life that is too short on sensor nodes. Developing effective routing protocols is the best way to overcome these challenges. An effective routing protocol can relay data from the network’s root node to its final destination. Therefore, the state of the art in underwater wireless acoustic sensor network (UWASN) routing protocols is assessed with an eye toward their potential for development. In real-world applications, sensor node positions are frequently used to locate relevant information. As a result, it is crucial to conduct research on routing protocols. Reinforcement learning (RL) algorithms have the ability to enhance routing under a variety of conditions because they are experience-based learning algorithms. Underwater routing methods for UWSN are reviewed in detail, including those that rely on machine learning (ML), energy, clustering and evolutionary approaches. Tables are incorporated for the suggested protocols by including the benefits, drawbacks, and performance assessments, which make the information easier to digest. Also, several applications of UWSN are discussed with security considerations. In addition to this, the analysis of node deployment and residual energy is discussed in this review. Furthermore, the domain review emphasizes UW routing protocol research difficulties and future directions, which can help researchers create more efficient routing protocols based on ML in the future.

Low Power Wake-Up Receivers for Underwater Acoustic Wireless Sensor Networks

This article reports two low power wake-up receiver (WuRx) circuits (Type A and B) for underwater acoustic wireless sensor networks. The proposed circuits realize the same novel method to extract the wake-up call from the acoustic signals received by a sensor node using different circuit topologies. This is accomplished by comparing the amplitude and the duration of the received pulses to a predefined code. A combination of these two parameters provides a safe and robust decoding system. The values and duration of the predefined code can be adjusted by tuning the biasing voltages in the circuits. The main advantages of the presented designs are modularity and tunability. To verify the operation of the proposed system, an ASIC has been realized. The WuRxs have been characterized in terms of tuning, duty cycle, and power consumption. Both WuRxs can consume less than 0.5. Type A occupies an area of mode = text0.058mm2, has a data rate of mode = text250bit/s, and presents the lowest power consumption reported, consuming 265nW and 61nW in active and sleep modes, respectively.

Impact of moving target on underwater positioning by using state measurement

The localization of moving targets in an underwater acoustic wireless sensor network (UAWSN) is inaccurate due to the various underwater forces (viscous, hydrodynamic forces, perturbation of underwater). The false measurements in the sensor network cause position errors and velocity errors which disrupt the localization of the moving target. A randomly fluctuated spillover effect is introduced in the present paper. The absorption losses generated due to the spillover effect cause false measurements of the moving target. Theorem 1 describes the genesis of these absorption losses and their consequences in UAWSN. The measurements from each moving target in the presence of absorption losses are formulated in the elliptical region. A joint probabilistic data association (JPDA) method is proposed to quantify the false measurements in the elliptical region. A moving target state estimation (MTSE) algorithm is proposed to eliminate the false measurements from the moving targets and to measure the localization of moving targets with the help of the propagation speed of targets. The theoretical measurements of position RMSE and velocity RMSE are verified with standard methods. The proposed MTSE method improves the localization performance of the moving targets by 29.42 % and reduces 32.16 % of position errors and 36.23 % of velocity errors up to 550 ​m. The proposed algorithm will be useful for the sub-aquatic Internet of underwater things (IoUT).

Vortex‐induced vibration effects in underwater acoustic wireless sensor networks

AbstractA randomly fluctuated vortex‐induced vibration (VIV) affects the localization of moving targets in an underwater acoustic wireless sensor network (UAWSN) to cause an offset time and time synchronization error which disturbs the localization of the non‐cooperative moving target. Definition 1, Theorem 1 has been introduced in the present work to describe the genesis and consequences of the VIV effect in UAWSN. An elliptic localization introduces the direct and indirect path measurements of the moving target. The standard Crammer Rao lower bound parameter quantifies the VIV effect. The compensation of vortex‐induced vibrations (CVV) algorithm is proposed to quantify the degradation of localization performance and to estimate the position of the moving target. The theoretical measurements of position error, velocity error with respect to the variation of noise, number of receiver sensors, and probability of line of sight errors are compared to the standard methods. The proposed CVV algorithm improves the localization performance by 32.24% and reduces 34.36% of position errors, and 37.46% of velocity errors up to 600 m. It can be useful for the sub‐aquatic internet of underwater things.

Asynchronous Pattern-Designed Channel Access Protocol in Underwater Acoustic Wireless Sensor Networks

Due to the significant propagation delay in underwater sensor networks, conflict retransmission in channel access protocols comes at a high cost. This poses a challenge in scenarios where multiple sensor nodes generate data frames with strong temporal correlations, such as in disaster warning applications. Traditional channel allocation and timeout-based retransmission mechanisms lead to considerable access delays, making it difficult to meet the requirements. To tackle this issue, we propose the asynchronous pattern-designed random access (APDRA) protocol. This protocol enhances the access probability by designing retransmission time intervals for data frames based on pattern design. Additionally, we introduce a successive interference cancellation (SIC) mechanism at the receiver for decoding. This mechanism facilitates the transformation of the conventional method of discarding conflicted data frames into iterative decoding, thereby enhancing transmission efficiency. Via the utilization of simulations, we compare the APDRA protocol conventional underwater medium access control (MAC) protocols and existing retransmission mechanisms. The results demonstrate that the APDRA protocol has the ability to improve both the transmission success ratio (TSR) and reduces the access delay to some extent.

Cross-Layer Protocol Based on Directional Reception in Underwater Acoustic Wireless Sensor Networks

The long propagation delay of acoustic links leads to the complex randomness of packet collision, which reduces the network packet delivery rate (PDR) and aggravates network congestion. A single vector hydrophone with directional reception characteristics can concentrate the reception gain on a certain direction, which can increase spatial reuse, reduce packet collision, and help to improve the performance of the underwater acoustic wireless sensor networks (UASNs). Herein, this paper proposes a cross-layer protocol with low interference and low congestion (CLIC) based on directional reception. An integrated routing-medium access control (MAC) design is also devised in the CLIC scheme to use the directional beams to create the least-interfering, highest-capacity data transmission links, weighing key factors affecting network performance to obtain routes with low collisions and low congestion. Simulation results show that the CLIC has a higher packet delivery rate (PDR) and higher energy efficiency compared to the QELAR, CITP, and VBF protocols.

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.

MOR: Multi-objective routing for underwater acoustic wireless sensor networks

Underwater acoustic wireless sensor networks (UAWSN) are becoming more and more extensive, and different application scenarios have different service quality requirements. Routing protocols that can meet different traffic transmission requirements are vital to the application of UAWSN in different scenarios. Due to the harsh environment of the underwater acoustic channel, the routing protocol of the UAWSN should consider the characteristics of the underwater channels. In this paper, a multi-objective routing (MOR) scheme is proposed for UAWSN applications, and relay selection algorithms (RSA) are devised for delay-sensitive (DS) and delay-insensitive (DIS) scenarios to meet different quality-of-service (QoS). For DS applications, RSA selects the relays taking into account of the energy and delay affected mainly by MAC time, node congestion and hops of the nodes for connecting from potential candidate node to sink, while the RSA mainly takes energy consumption and reliability into consideration for DIS case to choose desired relay. The results demonstrated that the MOR outperforms VBF and QELAR in terms of delay and energy consumption for DS applications, while it is performs better in terms of delay, energy consumption, packet delivery rate and lifetime for DIS applications.

Energy and Path-Aware-Reliable Routing in Underwater Acoustic Wireless Sensor Networks

In underwater acoustic sensor networks (UASNs), energy awareness, best path selection, reliability, and scalability are among the key factors that decide information delivery to the sea surface. Existing protocols usually do not combine such performance-affecting factors in information routing. As a result, the performance of such protocols usually deteriorates if multiple performance factors are taken into account. To cope with such performance deterioration, this article proposes two routing protocols for UASNs: energy and path-aware reliable routing (EPRR) and cooperative EPRR (Co-EPRR). Compared with the counterpart systems, the proposed protocols have been designed to deal with the problem of long propagation delays and achieve network reliability. The EPRR scheme uses nodes’ physical distance from the surface with its depth, which minimized the delay of packet transmission. The channel interaction time has been reduced, therefore, reducing unwanted channel effects on the data. Furthermore, the density of the nodes in the upper part of the network prevents data loss and limits the rapid death of the nodes. The second proposed scheme, Co-EPRR, uses the concept of routing information from the source to the destination on multiple paths. In Co-EPRR routing, the destination node can receive more than one copy of the data packet. This reduces unfavorable channel effects during data delivery. Both the schemes show good performance in terms of packet delivery ratio, received packet analysis, and end-to-end delay.

BDREA Betta and Dolphin Pods Routing via Energy Scarcity Aware Protocol for Underwater Acoustic Wireless Sensor Networks (UAWSNs)

There exist numerous applications for deploying Underwater Wireless Sensor Networks (UWSNs), including submarine detection, disaster prevention, oil and gas monitoring, off-shore exploration, and military target tracking. The acoustic sensor nodes are deployed to monitor the underwater environment, considering the area under observation. This research work proposes an energy scarcity-aware routing protocol for energy efficient UWSNs. Moreover, it aims to find the feasible region on the basis of the objective function, in order to minimize the energy tax and extend the network life. There are three different sensors nodes in the network environment, i.e., anchor nodes, relay nodes, and the centralized station. Anchor nodes originate data packets, while relay nodes process them and broadcast between each other until the packets reach the centralized station. The underline base scheme Weighting Depth and Forwarding Area Division Depth-Based Routing (WDFAD-DBR) for routing is based on the depth differences of the first- and second-hop nodes of the source node. The propose work, Betta and Dolphin Pods Routing via Energy Scarcity Aware protocol (BDREA) for packet forwarding from the forwarding nodes considers the first and second hops of the source node, i.e., the packet advancement, the network traffic, the distance to the centralized station, and the inverse normalized energy of the forwarding zone. It is observed that the proposed work improves the performance parameters by approximately 50% in terms of energy efficiency, and prolongs the network life compared to Dolphin and Whale Pod (DOW-PR) protocols. Furthermore, the energy efficiency directly relates to the other parameters, and its enhancement can be seen in terms of an 18.02% reduction in end-to-end delay when compared with the Weighting Depth and Forwarding Area Division Depth-Based Routing (WDFAD-DBR) protocol. Furthermore, BDREA improves the Packet Delivery Ratio (PDR) by approximately 8.71%, compared to DOW-PR, and by 10% compared with the benchmark, WDFAD-DBR, the energy tax by 50% in comparison to DOW-PR, the end-to-end delay by 18%, and the APD by 5% in comparison to WDFAD-DBR.

Statistical Channel Model and Systematic Random Linear Network Coding Based QoS Oriented and Energy Efficient UWSN Routing Protocol

Considering the significance of an energy efficient, delay tolerant and reliable communication protocol for underwater acoustic wireless sensor network (UWSN), this paper proposes a novel systematic random linear network coding (SRLNC) based transmission system examined over a robust statistical UWSN channel model. The derived statistical channel model deals with both the small-scale fading primarily caused by scattering and small wavelength changes and large-scale fading introduced due to node dislocation in the underwater acoustic medium. The proposed SRLNC transmission-based routing approach has been applied over the proposed underwater acoustic (statistical) channel model, and respective performance assessment has been conducted in terms of throughput, energy efficiency, delay and computational complexity by varying network condition parameters. The contributions such as low coefficient vector and Galois filed, low redundant message requirements, computationally efficient pre-coding scheme, iterative buffer flush and enhanced FEC based decoding make the SRLNC based routing protocol sufficiently robust to enable reliable, energy-efficient and delay resilient communication over UWSN. The proposed SRLNC based UWSN routing protocol and its efficacy over dynamic channel conditions affirm that it can be a potential solution for QoS-oriented mission critical underwater communication purposes.

Underwater sound speed profile parameters estimation in asynchronous network

AbstractThe technology of underwater wireless acoustic sensor networks (UWSNs) plays an important role in many commercial and military applications in underwater. In UWSNs, there exist many challenges posed by the specific characteristics of underwater acoustic channel, such as sound propagation speed is a function of depth with unknown parameters. Besides, time synchronization of anchor nodes is a crucial part of the applicable network. Time synchronization of anchor nodes as well as estimation of sound speed parameters considering an isogradient profile is explored here. While the previous efforts do not take into account these factors, this article assumes only one synchronized anchor node in the network and enables joint synchronization of the other anchor nodes and the estimation of the propagation delays between the anchor nodes using a weighted linear least square solution. Then, it uses the estimated propagation delays to estimate the unknown parameters of the sound speed profile using a conventional Gauss‐Newton algorithm with approximately three iterations to converge. Validation of the proposed method is done by the numerical simulations and to demonstrate the effectiveness of the proposed method we compare the results with Cramer‐Rao bound average.

MuLSi-Co: Multilayer Sinks and Cooperation-Based Data Routing Techniques for Underwater Acoustic Wireless Sensor Networks (UA-WSNs)

Designing an efficient, reliable, and stable algorithm for underwater acoustic wireless sensor networks (UA-WSNs) needs immense attention. It is due to their notable and distinctive challenges. To address the difficulties and challenges, the article introduces two algorithms: the multilayer sink (MuLSi) algorithm and its reliable version MuLSi-Co using the cooperation technique. The first algorithm proposes a multilayered network structure instead of a solid single structure and sinks placement at the optimal position, which reduces multiple hops communication. Moreover, the best forwarder selection amongst the nodes based on nodes’ closeness to the sink is a good choice. As a result, it makes the network perform better. Unlike the traditional algorithms, the proposed scheme does not need location information about nodes. However, the MuLSi algorithm does not fulfill the requirement of reliable operation due to a single link. Therefore, the MuLSi-Co algorithm utilizes nodes’collaborative behavior for reliable information. In cooperation, the receiver has multiple copies of the same data. Then, it combines these packets for the purpose of correct data reception. The data forwarding by the relay without any latency eliminates the synchronization problem. Moreover, the overhearing of the data gets rid of duplicate transmissions. The proposed schemes are superior in energy cost and reliable exchanging of data and have more alive and less dead nodes.

Energy Harvesting in Underwater Acoustic Wireless Sensor Networks: Design, Taxonomy, Applications, Challenges and Future Directions

In underwater acoustic wireless sensor networks (UAWSNs), energy harvesting either enhances the lifetime of a network by increasing the battery power of sensor nodes or ensures battery-less operation of nodes. This, in effect, results in sustainable and reliable operation of the network deployed for various underwater applications. This work provides a survey of the energy harvesting techniques for UAWSNs. Our work is unique than the existing work on underwater energy harvesting in that it includes state-of-the art techniques designed in the last decade. It analyzes every harvesting scheme in terms of its main idea, merits, demerits and the extent of the harvested power (energy). The description of the merits results in selection of the suitable scheme for the suitable underwater applications. The demerits of the addressed schemes provide an insight to their future enhancement and improvement. Moreover, the harvested techniques are classified into various categories depending upon the involved energy harvesting mechanism and compared based on the maximum and minimum amount of harvested power, which helps in selection of the suitable category keeping in view the power budget of an underwater network before deployment. The challenges in energy harvesting and in UAWSNs are described to provide an insight to them and to address them for further enhancement in the harvested extent. Finally, research directions are specified for future investigation.

Retraction Note: Design and simulation analysis of offshore tidal energy generating set system based on sensor network

Tidal energy refers to the potential energy and kinetic energy of tidal changes. It is a kind of energy that hides a huge amount of energy and can be regenerated endlessly. Tidal energy as an energy source is purely renewable energy. The tide rises and falls every day, and the energy is constant, so it will be endless. Power generation through tidal energy cannot only alleviate the energy shortage but also become the main additional energy source for people to carry out economic construction and development in areas near the sea. Because tidal power plants are usually built-in offshore areas with relatively small populations, they will not cause complicated problems such as flooding of farmland and immigration. In view of the shortage of energy and fuel in the world and the increasingly serious environmental and pollution problems, tidal energy has received widespread attention and influence all over the world due to its infinite reserves, lack of environmental pollution, and high predictability. Based on the submarine acoustic wireless sensor network platform, we have developed an experimental submarine acoustic ray sensor network platform, which provides an effective platform for testing and evaluating the submarine acoustic ray sensor network. This paper determines the capacity of TCF, the layout design of TCF in TCT, and the research on the collection system. Based on the underwater acoustic wireless sensor network platform, the underwater acoustic network experimental test system platform is being developed, and a feasible research plan is proposed for the detection and evaluation of the underwater acoustic wireless sensor network.

Link and stability-aware adaptive cooperative routing with restricted packets transmission and void-avoidance for underwater acoustic wireless sensor networks

In underwater acoustic wireless sensor networks (UAWSNs), the conventional routing protocols continuously transmit data packets containing the same information when a source node detects an event of interest. This approach, however, leads to high energy consumption, high interference and challenges the stability of the network due to heavy data load on the nodes close to water surface. To overcome these challenges, this article proposes two routing protocols for UAWSNs. They are, SRRPV: stability-aware routing with restricted packets transmission and void-avoidance and LS-ACRPV: link and stability-aware adaptive cooperative routing with restricted packets transmission and void-avoidance. In SRRPV, a source node detects the event of interest, generates and routes packets. Subsequent packets routing is performed only when a change in intensity of the event is detected. Due to restricted packets transmission, three-hop connected paths with suitable neighbors are chosen to overcome the existence of a void (non-availability of a suitable forwarder) and, therefore, control packets loss. Moreover, the defined packet holding time ensures that nodes with the highest available energy transfer the most packets by holding the packets for the shortest interval of time. This strategy, in combination with restricted packets transmission, achieves network stability. Since limited number of packets are routed, the LS-ACRPV protocol is designed that adds reliability to the SRRPV protocol by selecting a routing link with the highest probability of successfully delivering packets to the destination or using adaptive cooperative routing to combat severe link conditions. Unlike the conventional protocols, the proposed protocols do not require the geographical position coordinates of nodes, which is challenging in underwater environment as nodes change their positions with sea tides and currents. Extensive simulation results reveal promising performance of the proposed schemes in terms of energy expenditure, delay and network stability at the expense of low packets delivery due to restricted packets transmission.

A Study of Standardizing Frequencies Using Channel Raster for Underwater Wireless Acoustic Sensor Networks.

In this paper, we propose the method to standardize acoustic frequencies for underwater wireless acoustic sensor networks (UWASNs) by applying the channel raster used in the terrestrial mobile communications. The standardization process includes: (1) Setting the available acoustic frequency band where a channel raster is employed via the frequency specification analysis of the state-of-the art underwater acoustic communication modems. (2) Defining the center frequencies and the channel numbers as a function of channel raster, and the upper limit of the value of channel raster. (3) Determining the value of the channel raster suitable for the available acoustic frequency band via simulations. To set the value, three performance metrics are considered: the collision rate, the idle spectrum rate, and the receiver computational complexity. The simulation results show that the collision rate and the idle spectrum rate according to the value of channel raster have a trade-off relationship, but the influence of channel raster on the two performance metrics is insignificant. However, the receiver computational complexity is enhanced remarkably as the value of channel raster increases. Therefore, setting the value of channel raster close to its upper limit is the most adequate in respect of mitigating the occurrence of a collision and enhancing the reception performance. The standardized frequencies based on channel raster can guarantee the frequency compatibility required for the emerging technologies like the Internet of Underwater Things (IoUT) or the underwater cognitive radio, but also improves the network performance by avoiding the arbitrary use of frequencies.

Time-Synchronization Free Localization Scheme with Mobility Prediction for UAWSNs

Background: Underwater Acoustic Wireless Sensor Network supports a lot of civil and military applications. It has come out as an effective tool to explore the ocean area of the earth. Sensor deployed underwater can help to relate the events occurring underwater with the rest of the world. To achieve the goal, the information gained from the sensors needs to be tagged with their real-time locations. Objective: To study the effect of the mobility of the sensor nodes on the accuracy of the location estimation during the localization period and develop a localization scheme which can give an accurate result by predicting the mobility behavior of the sensors. Methods: In this paper, a time-synchronization free localization scheme for underwater networks has been presented. The scheme employs a mobile beacon in the network to move vertically and broadcast the beacon messages. Results: The performance evaluation shows that the scheme reduces the error in location estimation caused by the mobility of the sensors by predicting their further location according to the mobility pattern of the sensor node. In an existing localization scheme, nodes are localized without time-synchronization but the scheme does not consider the mobility of the senor between the reception of two messages. The result of shows that the proposed localization scheme has achieved success in reducing the localization error by introducing the mobility behavior of the sensors in the existing localization scheme. Conclusion: localization scheme without a need of time-synchronization is presented. The main reason of the inaccuracy of a localization scheme is the mobility of the sensor node during the range estimation. The accuracy of a localization scheme can be improved by prediction the mobility pattern of the sensor during a localization period.

Trusted node selection in clusters for underwater wireless acoustic sensor networks using fuzzy logic

Cluster based routing are the popular techniques in Underwater Wireless Acoustic Sensor Networks (UWASNs) owing to its advantages like better network life time, low energy consumption and scalability. However selection of trusted cluster head and cluster members is a challenging task due to the divergent features and constraints of UWASNs. In this paper we propose a trusted cluster head and member nodes selection scheme using fuzzy logic. The scheme works in the following steps. Initially the security check of the member nodes in the cluster are performed using a light weight XOR encryption algorithm in order to authenticate the nodes. Secondly, the trusted node is chosen based on trust value using fuzzy logic rules. The trust value of a node is calculated based on the fuzzy parameters such as distance, energy and relative mobility of the node. The scheme is simulated in MATLAB. It performs better when compared with the existing schemes in terms of malicious node detection and packet delivery.