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Cellular Clustering-Based Interference-Aware Data Transmission Protocol for Underwater Acoustic Sensor Networks
Abstract
Recently, the development of three-dimensional interference-aware data transmission methods has attracted the attention of scholars due to the increased interest in exploiting and studying the underwater acoustic sensor networks (UASNs). In this paper, an interference aware data transmission protocol based on cellular clustering architecture is proposed. The protocol involves two steps. The first one is an inter-cell time division multiple access (TDMA) scheduling, which reduces acoustic interference by restricting simultaneous data transmission via adjacent routing paths; and the second one is an intra-cell hierarchical routing, which targets efficient data collection in the submarine and reliable data transmission from the seabed to the surface. Moreover, a novel Ekman spiral-based low-cost location prediction method and a void hole recovery scheme are adopted in each step to support the practicability of proposed protocol. Theoretical analysis and simulations indicate that the proposed protocol has advantages related to the quality of service (QoS) of UASNs because the signal interference is significantly mitigated.
... The joint clustering and routing protocol (JCRP) for 3D UASN selects cluster heads based on residual energy and the weighted cost of network connectivity [12]. The cellular-clustering-based interference-aware data transmission protocol (CIDP) for 3D undersea exploration uses TDMA scheduling and hierarchical routing to reduce interference and improve data transmission [13]. In [14], a multi-hop energy-efficient routing protocol was proposed to improve the energy efficiency of data distribution, especially for nodes far from surface sinks. ...
... And t guard is designed to account for the uncertainty in the propagation delay estimates, ensuring that even if there is a slight delay in the signal reaching its destination, it will not interfere with the subsequent transmission slot. Then, the transmission time t TX i of the ith cluster head node is given by: (13). In this case, the actual transmission time of each node should be adjusted as follows: ...
... where denotes the transmission delay of the cluster head node Si. Note that if is large, may be negative in (13). In this case, the actual transmission time of each node should be adjusted as follows: ...
Underwater acoustic sensor networks (UASNs) are critical to a range of applications from oceanographic data collection to submarine surveillance. In these networks, efficient energy management is critical due to the limited power resources of underwater sensors. The LEACH protocol, a popular cluster-based protocol, has been widely used in UASNs to minimize energy consumption. Despite its widespread use, the conventional LEACH protocol faces challenges such as an unoptimized cluster number and low transmission efficiency, which hinder its performance. This paper proposes an improved LEACH protocol for cluster-based UASNs, where the cluster number is optimized with an underwater energy propagation model to reduce energy consumption, and a transmission scheduling algorithm is also employed to achieve conflict-free parallel data transmission. Replication computing is introduced to the LEACH protocol to reduce the signaling in the clustering and data transmission phases. The simulation results show that the proposed protocol outperforms several conventional methods in terms of normalized average residual energy, average number of surviving nodes, average round when the first death node occurs, and the number of packets received by the base station.
... Radio waves are substantially attenuated in seawater. Electromagnetic waves with a frequency of 30 to 300 Hz can break through more than 100 m of saltwater [5]. It does, however, necessitate a lengthy receiving antenna, which a small sensor node cannot provide. ...
... For case, changes in temperature, pressure, salinity, and other factors cause acoustic signals to fluctuate in speed. (5) Since these sensors are battery-powered and it is expensive to replenish or replace their batteries, energy is a limited resource. (6) The network topology is frequently altered by water currents, and the system must periodically adjust to new topological alterations0. ...
... The weighted values of nearby nodes are used to determine the best route. The authors proposed a 3D interference-aware routing protocol, cellular clustering-based interference-aware data transmission protocol (CIDP) [5] for submarine explorations. To minimize the effects of acoustic interference, CIDP works on inter-cell time division multiple access (TDMA) scheduling by restricting parallel data transmission and uses intracell routing for effective data collection. ...
Wireless transmission of information using water as a communication channel is one of the potential technologies for the progress of potential underwater observation systems including applications from aquaculture to the oil industry, submarine detection, instrument monitoring, and forecast of natural turbulence and study of marine life. Underwater wireless sensor networks applications are exhilarating but demanding at the same time. Some of the challenges faced by underwater networks are the movement of nodes in three-dimensional space because of which the network could not be well thought-out as a fixed topology, limited bandwidth, exceedingly low data rates, limited battery power, failures due to pollution, and corrosion, and a lot more. Additionally, as acoustic communications consume more power than terrestrial radio ones do, more sophisticated signal processing methods are needed at the receiver to make up for the channel's deficiencies. One of these difficulties is creating a routing protocol for the complexity of an underwater environment. The major aim of all these protocols is to advance data packets toward the sink to lessen the propagation delay, lessen energy expenditure, and utilize the least amount of bandwidth by restricting the broadcasting of multiple copies of the data packet. This article surveys various routing schemes and various challenges involved in the design and development of these routing schemes.
... Zhang et al. [25] suggested a Clustering-based Interference-aware Data Transmission Protocol (CIDP), depending on the cluster approach. The introduced work is used to develop a three-dimensional interference-aware transmission of data. ...
... Each node has an initial energy of 40000 J, transmit and receive power is 50w and 0.159 W and a data packet size is 128(bit) at the rate of 10(kbps). The proposed DOCA is estimated by relating the efficiency of the proposed method using existing methods such as EOCA [20], TSDBG [23], and CIDP [25]. ...
... The performance evaluation of the proposed CT-EDS-BBOA model is compared with the existing techniques such as EOCA [20], CIDP [25], TSDBG [23], Energy Efficient ...
At present, underwater wireless ad hoc networks (UWAN) are widely used in enormous applications. At the same time, UWAN faced many security issues, like energy leaks. The energy hole will make the network lifetime end soon. However, most existing underwater research has not taken security as serious threat. This article aims to provide a new secure data transmission scheme in UWAN, in which the management and deployment of UWAN is typically done by a trusted authority. The proposed Cluster Tree Enhanced Dempster Shafer based Bidirectional Butterfly Optimization algorithm (CT-EDS-BBO) will be divided into three phases. Initially, the cluster-based tree routing protocol designed for cluster formation, CH selection process, and routing process establishment. In the second phase, the Enhanced Dempster Shafer Evidence Theory uses the fusion rule to evaluate the trust value for each node, which is used to determine the security of each node and to detect the Malicious Node. Finally, the Bidirectional Butterfly Optimization algorithm model is designed to avoid the energy hole issue and to allocate a routing channel for secure data transmission over UWAN. The results obtained from simulation analysis demonstrate that the proposed CT-EDS-BBO has observable benefits over the conventional methods with a Packet Delivery Ratio of 90%, energy consumption of 0.14 J, a network lifetime of 732 s for 200 rounds, and an end-to-end delay of 0.12 s.
... To better overcome the drawbacks of scheduling-based MAC protocols, large-scale node scheduling and clustering algorithms have gradually become a research focus for improving network performance [20,21]. The classification and hierarchical ideas in clustering algorithms reduce the complexity of underwater networks and the number of data transmissions for user nodes. ...
... To sum up, in the course of a round of game, nodes with greater energy tend to become cluster heads and thus obtain the maximum benefits. Nodes with lower energy receive smaller penalty values r i during the course of the game, and Formula (20) can be used to show that the strategy of choosing NCH has greater benefits. Ultimately, an equilibrium state is reached during the game between the nodes. ...
Underwater sensor networks (UWSNs) play a vital role in marine exploration and environmental monitoring. However, due to the characteristics of underwater acoustic channels such as high delay, low bandwidth, and energy limitation, the design of an underwater media access control (MAC) protocol has brought great challenges, and existing MAC protocol designs rarely consider the influence of channel interference factors in networking. Therefore, this paper proposes a collision avoidance MAC protocol for clustering underwater sensor networks. The protocol first classifies users by combining the channel characteristics of underwater nodes and the distance measurement between nodes. Then, based on the clustering network, according to the channel correlation distance measurement between nodes and the communication range of the cluster head (CH), the transmit power in clusters is controlled to reduce the lifetime of the network based on the cumulative reduction in node power consumption. Finally, the cluster structure in each cluster is used to schedule the transmission of member nodes in the cluster, and at the same time, the energy consumption of nodes is reduced while multi-node collision-free transmission is realized. The simulation results show that the throughput of the proposed adaptive power control clustering MAC protocol (APCC-MAC) is 26.5% and 19.5% higher than that of packet-level slot scheduling (PLSS) algorithm and Cluster-Based Spatial–Temporal Scheduling (CSS) algorithm, respectively, providing better communication performance and stability for clustered underwater acoustic networks.
... The current communication history can be stored in local memory by each node [19]. Water flow does not quickly impact sensor nodes and they retain a consistent transmission radius [20,21]. ...
... We carry out the evaluation of the ELOORP with the underlying CSMA MAC protocol. The forwarding node can broadcast the data packet while the channel is open [20]. We primarily evaluate the ELOORP procedure to the following two factors using different quantitative data and scenarios: The size and broadcast area of the network. ...
Due to advancements in WSN, there is a growing interest in underwater acoustic sensor networks (UASNs), which are also widely used in disaster prevention and marine engineering research. UASNs present a number of unique challenges, such as continuous sensor node mobility. A recent study found that in subaquatic environments, location-based opportunistic routing strategies can deliver exceptional quality of service (QoS). This study presents ELOORP, a fast operating framework that leverages localization-based optimized opportunistic routing protocol for various UASNs platform applications. Our simulations in NS-2 demonstrate that the protocol outperforms current protocols in terms of energy economy and quality of service. Examining the scalability of the suggested routing methods involves varying the size of the network and the transmission range. With network scales between 100 and 500, the evaluation's results demonstrate that the ELOORP works better than the present routing protocols.
... (3) Nodes in a particular layer send packets to that layer's cluster head, who then transmits packets to the cluster head. Sensor nodes have uniform transmission radius and are not impacted by water flow in a short period of time [22,23]. ...
... To evaluate the SROA, we employ the Carrier Sense Multiple Access (CSMA) as the underlying MAC protocol. Specifically, when the channel is not occupied, the forwarding node is able to broadcast the data packet; otherwise, it backs off and discards the packet after five times of backing off [22]. We mainly evaluate the SROA protocol in several quantitative metrics and scenarios against the two different parameters: Network size and transmission range. ...
With the advancements in wireless sensor networks and the Internet of Underwater Things (IoUT), underwater acoustic sensor networks (UASNs) have attracted much attention, which has also been widely used in marine engineering exploration and disaster prevention. However, UASNs still face many challenges, including high propagation latency, limited bandwidth, high energy consumption, and unreliable transmission, influencing the good quality of service (QoS). In this paper, we propose a routing protocol based on the on-site architecture (SROA) for UASNs to improve network scalability and energy efficiency. The on-site architecture adopted by SROA is different from most architectures in that the data center is deployed underwater, which makes the sink nodes closer to the data source. A clustering method is introduced in SROA, which makes the network adapt to the changes in the network scale and avoid single-point failure. Moreover, the Q-learning algorithm is applied to seek optimal routing policies, in which the characteristics of underwater acoustic communication such as residual energy, end-to-end delay, and link quality are considered jointly when constructing the reward function. Furthermore, the reduction of packet retransmissions and collisions is advocated using a waiting mechanism developed from opportunistic routing (OR). The SROA realizes opportunistic routing to choose candidate nodes and coordinate packet forwarding among candidate nodes. The scalability of the proposed routing protocols is also analyzed by varying the network size and transmission range. According to the evaluation results, with the network scale ranging from 100 to 500, the SROA outperforms the existing routing protocols, extensively decreasing energy consumption and end-to-end delay.
... (3) The underwater environment is generally stable for sensor nodes. Sensor nodes have uniform transmission radius and are not impacted by water flow in a short period of time [22]- [23]. ...
... To evaluate the SROA, we employ the Carrier Sense Multiple Access (CSMA) as the underlying MAC protocol. Specifically, when the channel is not occupied, the forwarding node is able to broadcast the data packet; otherwise, it backs off and discards the packet after five times of backing off [22]. We mainly evaluate the SROA protocol in several quantitative metrics and scenarios against the two different parameters: network size and transmission range. ...
With the advancements of wireless sensor networks and the Internet of Underwater Things (IoUT), underwater acoustic sensor networks (UASNs) have attracted much attention, which also has been widely used in marine engineering exploration and disaster prevention. However, UASNs still face many challenges, including high propagation latency, limited bandwidth, and energy consumption, influencing the reliability of data transmission. In this paper, we propose a routing protocol based on the on-site architecture (SROA) for UASNs to improve network scalability, energy efficiency, and transmission reliability. The on-site architecture adopted by SROA is different from the most architectures in that the data center is deployed underwater which makes the sink nodes closer to the data source. The SROA is a cluster-based protocol which adapts to the changes of network scale and avoids single-point failure through the decentralized and distributed sensor networks. To seek optimal routing policies, the factors of energy, delay, and link quality are considered jointly in the reward function of Q-Learning. Moreover, the reduction of packet retransmissions and collisions is advocated using a waiting mechanism developed from opportunistic routing (OR). The SROA realizes opportunistic routing to choose candidate nodes and coordinate packet forwarding among candidate nodes. Scalability of the proposed routing protocols is also analyzed by varying the network size and transmission range. According to the evaluation results, with the network scale ranging from 100 to 500, the SROA outperforms the existing routing protocols, extensively increasing packet delivery ratio and decreasing end-to-end delay.
... Since the development of IoUT, various energy saving routing mechanisms have been proposed. [22][23][24][25][26][27][28][29] As the conditions of underwater scenario is complex which leads to non-replacement of batteries on regular basis. Hence, energy consumption of sensor nodes becomes one of the serious concerns to be handled. ...
... However, due to multi-hop communication, it suffers from hot-spot problem. Shortest queue strategy leads to complexity overhead CIDP 23 : The authors proposed this protocol for submarine explorations. The proposed work by the authors work on two fundamental steps. ...
Internet of Underwater Things (IoUT) comprises various resource‐constrained sensor nodes; therefore, the routing followed in acoustic medium underwater should be energy efficient to preserve their energies. Due to large area covered in the scenarios of underwater, the multi‐hop communication leads to energy hole problem. Therefore, Energy hole mitigation through Optimized Cluster Head (CH) selection and Strategic Routing (EOCSR) in IoUT is proposed in this paper. The proposed work not only optimizes CH selection using Tunicate Swarm Algorithm but also incorporates strategic routing to address energy hole problem. The simulation results show that EOCSR improves stability and lifetime of network by 16.8% and 17.7%, as compared with recently proposed Moth Flame Optimization‐based routing method.
... In [81], a bio-inspired multi-objective evolutionary routing protocol was conducted for UASNs. In [82], an interference-aware routing protocol based on cellular clustering architecture was proposed for UASNs. Also of relevance, an AUV-based data delivery protocol was provided by [83] to ensures data delivery within a given time interval by adjusting the motions of nodes. ...
Underwater acoustic sensor networks (UASNs), which are formed by a number of interconnected mobile vehicles and static sensors, have emerged as a promising solution to explore and utilize the ocean resources. Typically, the localization, communication and control are the fundamental services for the applications of UASNs. Although they are closely related, the localization, communication and control issues are usually separately tackled. The separate design directly affects the localization accuracy, transmission reliability and control efficiency, especially for resource-constrained UASNs. In this regard, it is essential and necessary to co-design the localization, communication and control systems for UASNs. At present, the theoretical framework of the above integration design is still in the construction phase, and some key problems remain unresolved. Therefore, this article aims to give a survey on the integration design of localization, communication and control for UASNs. We first present the communication architecture, through which the main challenges aiming at the integration design are analyzed. After that, a holistic survey on the underwater localization, communication and control basics is provided. Followed by this, the recent advances on the integration design are given. At last, we make an outlook to the future research directions on the integration design of localization, communication and control for UASNs.
... The first is an intra-cell hierarchical routing system that aims to achieve reliable data transmission from the seabed to the surface and efficient data collection within the submarine. The second is an inter-cell time division multiple access (TDMA) scheduling system that minimizes acoustic interference by limiting simultaneous data transmission via adjacent routing paths [14]. Sun et al. have presented an adaptive sampling algorithm (ASA) throughout a submarine wireless sensor network [13]. ...
Underwater Wireless Sensor Networks (UWSN) consists of various sensors and other components that communicate with each other. UWSN has several uses such as seismic monitoring, subsurface navigation and catastrophe prediction and avoidance. This could lead to issues with power consumption, battery life, time synchronization, location, and sensor installation, among others. Security is also an important consideration for UWSN, as it is vulnerable to attacks. In order to reduce power consumption and counter security threats, an innovative Energy-aware Routing protocol (EWR) is proposed that uses an Improved Circle Search Algorithm (ICSA). EWR employs cooperative routing to improve network efficiency and performance. Finally, the performance of the suggested technique is evaluated using simulations run on NS2 software and results are compared to state-of-the-art protocols like IWDT, RE-PBR, and SEECR based on several metrics, including detection accuracy, energy consumption, transmission loss, throughput, and latency. It shows that the suggested method outperforms the alternatives with more efficiency and better performance.
... The key to this method is how to find the nearest node to the target node and use it as the next hop during the forwarding process. The energy-controlled routing protocol [38][39][40][41][42] primarily addresses the issue of overall energy balancing in a network, aiming to maximize the overall network lifetime while ensuring reliable data transmission. By efficiently distributing energy usage among network nodes, the protocol helps to prevent premature energy depletion in certain nodes, thus extending the overall network lifetime. ...
The establishment of the Underwater Internet of Things (UIoT) and the realization of interconnection between heterogeneous underwater intelligent devices are urgent global challenges. Underwater acoustic networking is the most suitable technology to achieve UIoT for medium to long ranges. This paper presents an underwater Wi-Fi network, called uw-WiFi, that utilizes a master–slave mode architecture. uw-WiFi is dedicated to solving the problem of underwater acoustic networking with limited coverage range and number of nodes. To ensure the reliability of different types of data in the network, a reliable segmentation transmission protocol based on data type is designed. Additionally, on-demand scheduling based on the reservation MAC protocol is developed to solve the channel resource sharing problem. The uw-WiFi system has undergone shallow sea tests, and the experimental results demonstrate that the uw-WiFi network is capable of achieving a network throughput of 500 bps or higher, indicating superior network performance.
... In the marine environment, several underwater wireless sensor nodes are deployed to support a variety of applications including surveillance, navigation, data collection, resource identification, and disaster prevention [1][2][3]. Each sensor node is equipped with an acoustic modem since UWSNs communicate through auditory waves [4]. ...
... Hence, the data delivery rates are increased at ferry nodes to improve data processing. Zhang et al. [18] have 6 evaluated an interference-aware data transmission protocol depending on the architecture of cellular clusters. There are two steps in the protocol. ...
In recent times, the research community has demonstrated significant interest in Underwater Wireless Sensor Networks (UWSNs), where extensive sensor deployments in oceans and rivers aim to monitor the underwater environment. Energy consumption poses a primary challenge due to the difficulty of replacing or recharging batteries in these environments. Existing studies have employed K-Means technology to minimize power consumption in underwater transmission nodes. However, these studies have often overlooked the consideration of residual energy and void region creation in their optimization approaches. To address these challenges, we introduce a novel Hybrid path finder-based vortex search (HPF-VS) algorithm, utilized for cluster head selection and optimization of node locations and remaining energy. To extend network coverage beyond limited transmission ranges, inaccessible nodes at the network periphery employ the improved Dwarf Mongoose Optimization (IDMO) algorithm. Our proposed techniques demonstrate superior performance compared to existing methods, showcasing minimized energy consumption, reduced delay, improved packet delivery ratio, and enhanced throughput. Specifically, the proposed approach achieves a delay of 2.01 seconds and a throughput of 32.21 Kbps, surpassing the performance of state-of-the-art methodologies we benchmarked against.
... In [15], authors have introduced cellular clustering architecture to reduce interference for underwater wireless data transmission. The approach is based on inter-cell time division multiple access (TDMA) scheduling, and intra-cell hierarchical routing. ...
Interference minimization whether on topology or routing level has been a prominent concern in wireless sensor networks (WSNs). Existing graph-based approaches focus on minimizing whole topology and network interference. Work on having an interference minimum routing path on bidirectional connected graph models of WSNs is still left to explore under different interference models. So, this paper focuses on establishing an efficient routing path from the source to the destination node of minimum total link interference and maximum receiver node interference by optimally balancing between both the interference levels on any bidirectional connected graph model of WSN. We have proposed a dual-interference model based optimization (DIMO) routing algorithm by engaging ant colony optimization technique with two distinct interference models simultaneously that are link SUM interference model and receiver interference model. Moreover, a new interference model named as Disc-SUM model has also been developed whose implementation with Dijkstra’s algorithm results in a dual-interference minimized routing path in quadratic time complexity. Simulation work has been carried out to validate the DIMO algorithm and the Disc-SUM model for implementing a routing path between the source to the destination node with optimally reduced total link interference, maximum receiver node interference, total transmission cost, and hop counts.
... These issues can be addressed to get a more refined performance. Zhang et al. [32] have proposed a cellular clustering based routing protocol where time division multiple access (TDMA) is applied in inter-cell communication to reduce interference. Cluster based protocol is energy efficient but suffers from hot spot issues due to high energy consumption of upper layers. ...
The Underwater sensor network (UWSN), also known as Marine Sensor Network (MSN), is gaining increasing attention due to its applications in the monitoring of the marine environment and assisting Marine Intelligent Transportation Systems (MITS). Such systems provide in-vehicle assistance services (i.e., traffic monitoring and driver alerts) by gathering transportation and environmental information. Though very promising, there are several barriers to developing energy-efficient communication protocols for heterogeneous MSN, including selecting optimal routing paths twinned with the lifetime of these sensor nodes along the path, which are restricted due to the limited energy storage capacity. Hereby, the selection of an optimal route path also necessitates harvesting and management of the sensor nodes’ energy. To facilitate this, the current work presents REER-H, a Reliable Energy Efficient Routing protocol with Harvesting for cluster-based MSN capable of multi-source energy harvesting and an incorporated energy management technique. Incorporating three separate layers of the protocol stack, namely, network, MAC, and physical layers, REER-H uses its proposed adaptive scheduling technique to support collision-free data transmission by assigning adaptive time slots based on demand and data load. Also, the proposed integrated energy harvesting and management solves the energy hole problem and enhances the overall network lifetime. In comparison to the existing cooperative and cluster-based energy-efficient routing protocols for underwater maritime communication, the simulated results using Network Simulator-3 (NS3) reveal that the proposed scheme remarkably enhances the overall network performance in terms of packet delivery ratio, throughput, lifetime energy consumption, and end-to-end delay for MSN.
... PTP, which stands for Precision Time Protocol, is a protocol that was established to perfectly synchronize the time in industrial and automation networks. It is accurate to within microseconds, and it is capable of supporting wired as well as wireless communications [10,11,12,13]. ...
Performance of dense wireless sensor networks is often degraded due to communication interference and time synchronization issues. Existing machine learning & deep learning models that propose bioinspired & pre-emptive packet-analysis solutions for these tasks either have high complexity, or high deployment costs. Moreover, these models cannot be scaled for heterogeneous node & traffic types, which limits their applicability when applied to real-time scenarios. To overcome these issues, this text proposes design of an interference-aware routing model with time synchronization capabilities for dense wireless sensor network deployments. The network initially collects temporal clock states & packet delivery performance of different nodes on heterogeneous traffic scenarios. These traffic patterns are converted into frequency, entropy, Gabor, and Wavelet components. The converted components are used to train an ensemble set of Naïve Bayes (NB), k Nearest Neighbour (kNN), Multilayer Perceptron (MLP), and Support Vector Machine (SVM) classifiers. These classifiers assist in identification of optimal clock deviations and set of routing paths. These routing paths are further fine-tuned via use of a Bacterial Foraging Optimization (BFO) Model, which assists in identification of interference-aware paths. The BFO Model uses a temporal fitness function that fuses throughput, communication delay, energy levels, and packet delivery performance for different set of contextual communications. Due to which, the model is able to showcase lower end-to-end delay, higher throughput, lower energy consumption, and higher packet delivery performance when compared with existing routing methods under high density nodes & heterogeneous network scenarios. The model showcases 99% PDR, 18.3% lower delay, 19.5% higher energy efficiency and 10.4% lower delay levels when compared with existing methods.
... Therefore, the data-collection-oriented UASNs are usually multi-hop networks, in which the data generated at the sensor nodes are transmitted to the sink node hop-by-hop. An interferenceaware data transmission protocol named the cellular clustering-based interference-aware data transmission protocol (CIDP) is proposed in [11]. This protocol employs a time division multiple access (TDMA) scheduling scheme to reduce interference and a layered routing scheme to achieve reliable data transmission in UASNs. ...
Underwater acoustic channels are characterized by long propagation delay, limited available bandwidth and high energy costs. These unique characteristics bring challenges to design media access control (MAC) protocol for underwater acoustic sensor networks (UASNs). Especially in data-collection-oriented UASNs, data generated at underwater nodes are transmitted hop-by-hop to the sink node. The traffic loads undertaken by nodes of different depths are different. However, most existing MAC protocols do not consider the traffic load imbalance in data-collection-oriented UASNs, resulting in unfairness in how the nodes transmit their own generated data. In this paper, we propose a novel traffic-aware fair MAC protocol for layered data-collection-oriented UASNs, called TF-MAC. TF-MAC accesses a medium by assigning time slots of different lengths to each layer via different traffic loads to achieve traffic fairness of nodes. To improve throughput and avoid collision in the network, an overlapping time slot division mechanism for different layers and multi-channel allocation scheme within each single layer is employed. Considering the time-varying traffic loads of the nodes, an adaptive packet length algorithm is proposed by taking advantage of the spatial-temporal uncertainty of underwater channels. A sea experiment was conducted to prove the spatial-temporal uncertainty of UASNs, which provides a feasibility basis for the proposed algorithm. Simulation results show that TF-MAC can greatly improve the network performance in terms of throughput, delay, energy consumption, and fairness in the layered data-collection-oriented UASNs.
... By capturing data and sending it to ground stations, UWSNs serve an important role in ocean research and monitoring. The sensor nodes when deployed underwater needs to sustain for a longer period to deliver optimized performance [15]. It is due to the reason that circumstances in the underwater scenario are dynamic and needs to be given special care when it comes to routing [16]. ...
Oceanographic data gathering, pollution monitoring, offshore exploration, catastrophe avoidance, aided navigation, and tactical surveillance are all expected to benefit from the Internet of Underwater Things (IoUT). However, the viability of various applications in underwater scenarios is possible only if the routing among the sensor nodes employed is strategically optimized. This paper proposes Strategic Cooperative Routing for IoUT (SC ² R) that employs a cooperative node for data collection from each Cluster-Head (CH). CH selection is done through the energy and distance parameters. The cooperative nodes are positioned on water surface, other nodes being placed in the underwater terrain. This cooperative routing helps in the data collection for the time-critical scenario as it avoids multi-hop communication among the sensor nodes underwater. Due to decreased number of hops of communication, the delay in data transmission is reduced. The simulation results illustrate the efficacy of the proposed routing technique in comparison to competitive algorithms. The proposed protocol outperforms state of art routing protocols in terms of Network Lifetime and End to End Delay (EED).
... Since the development of WSN-based IoT, multitudinous routing methods have been presented. [28][29][30][31][32][33][34][35] The network conditions are complex and dynamic; hence, it makes the replacement of battery quixotic. Consequently, the energy expenditure of sensor nodes is a crucial concern which seeks research attention. ...
Technological advancements in the area of the Internet of Things have fostered the development of multi‐hop architectures pertaining to applications seeking large network areas. However, while exploiting such applications, the sensor devices being used are made to communicate through multi‐hop routing techniques, burdening the relay nodes. Hence, it leads to a hot‐spot problem, as the nodes passing on the data, that is, relay nodes, consume their energy at a large magnitude. To solve this issue, in this paper, we propose a novel optimized routing technique to mitigate hot‐spot problem (NORTH) for wireless sensor network (WSN)‐based IoT. We employ the tunicate swarm algorithm (TSA) to optimize the cluster‐based routing, specifically the selection of cluster head (CH) of each cluster by using some novel parameters. These parameters include energy status, a distance of a node from the sink and other nodes, load balancing, node proximity, and average energy stock of the network. We investigate two network scenarios, that is, when a sink is placed inside the network and otherwise, to give an optimized solution for every case. Further, to mitigate the hot‐spot problem, the relay node is selected in a cluster with the same mechanism as CH, which performs the task of data forwarding. The simulation analysis of NORTH reveals the supremacy of the proposed work against the recently proposed algorithms, based on various performance metrics, namely, network longevity, stability duration, throughput, and the network's remaining energy.
... Literature [23] examines the challenges posed by technologies, standards, supervision, and other factors in the field of big data security in the cloud computing environment, and proposes a reference framework for cloud computing security as well as the major research topics within it. Literature [24], combined with the application of real-time collection and processing of large-scale data, proposed a real-time processing method of large-scale data for high-speed data stream and provided an effective means for speed optimization and real-time processing of big data encryption and decryption algorithm. ...
There is a lack of fairness in market competition and disorder of order as a result of the lack of supervision. OCH (online car-hailing) driver accidents are also reported frequently, causing a slew of social and traffic safety issues. In this paper, we reconstruct the logical path of OCH platform data legal supervision in China’s big data era. We propose a big data encryption algorithm based on data redundancy technology that combines the characteristics of the ECC (Elliptic Curve Cryptography) and AES (Advanced Encryption Standard) block cipher modes in terms of computing speed, parallelism, and security. The system can process large amounts of network data and detect distributed denial of service (DDOS) attacks in real time. The observed feature change trend charts before and after the attacks show significant differences, demonstrating that the proposed features can better distinguish normal traffic from abnormal traffic.
... As soon as clusters were made, the CHN allocates channels to send data through. The CMN sends data based on the distribution that might avoid collisions [9]. CHNs are then responsible for aggregation, which might reduce data redundancy and cut down on the number of data packets that need to be sent to the SN, which saves energy [10]. ...
In recent years, the underwater wireless sensor network (UWSN) has received a significant interest among research communities for several applications, such as disaster management, water quality prediction, environmental observance, underwater navigation, etc. The UWSN comprises a massive number of sensors placed in rivers and oceans for observing the underwater environment. However, the underwater sensors are restricted to energy and it is tedious to recharge/replace batteries, resulting in energy efficiency being a major challenge. Clustering and multi-hop routing protocols are considered energy-efficient solutions for UWSN. However, the cluster-based routing protocols for traditional wireless networks could not be feasible for UWSN owing to the underwater current, low bandwidth, high water pressure, propagation delay, and error probability. To resolve these issues and achieve energy efficiency in UWSN, this study focuses on designing the metaheuristics-based clustering with a routing protocol for UWSN, named MCR-UWSN. The goal of the MCR-UWSN technique is to elect an efficient set of cluster heads (CHs) and route to destination. The MCR-UWSN technique involves the designing of cultural emperor penguin optimizer-based clustering (CEPOC) techniques to construct clusters. Besides, the multi-hop routing technique, alongside the grasshopper optimization (MHR-GOA) technique, is derived using multiple input parameters. The performance of the MCR-UWSN technique was validated, and the results are inspected in terms of different measures. The experimental results highlighted an enhanced performance of the MCR-UWSN technique over the recent state-of-art techniques.
In the realm of underwater wireless communication, vast oceanic expanses often demand large-scale deployment of Underwater Wireless Sensor Networks (UWSNs). UWSNs rely on acoustic communication channels, presenting distinct challenges like prolonged propagation delays, restricted bandwidth, and dynamic topologies. Furthermore, the far-reaching and multi-path nature of acoustic signals results in significant hidden terminal problems and ubiquitous interference between neighboring nodes. Therefore, an efficient medium access control (MAC) protocol is crucial for optimizing UWSN performance. This paper proposes IC-MAC, a MAC protocol tailored for UWSNs to avoid collisions and improve network performance. IC-MAC employs distributed clustering to group sensor nodes and the cluster head degree is defined for each node, which is a coefficient that accentuates nodes characterized by a higher incidence of collision associations. To identify interfering nodes and construct an interference-free graph, an interference identification algorithm is proposed. In addition, a heuristic graph coloring technique, guided by particle swarm optimization (PSO), allocates time slots efficiently to achieve collision-free transmission scheduling and enhanced spatial reuse. Simulations demonstrate the effectiveness of the IC-MAC protocol in enhancing throughput, reducing delay, and improving packet delivery ratio and energy efficiency. This is achieved through efficient spatial resource utilization and robust management of collisions and interference, specifically tailored for underwater acoustic channels, outperforming existing MAC protocols.
Energy consumption has been the focus of routing protocols in underwater acoustic sensors networks (UASNs), and many cluster-based routing protocols have been proposed to optimize the energy consumption. However, there are the "hotspot" problem resulting from frequent data forwarding by cluster heads and energy inefficiency caused by the transmission of data packets from shallow water to deep water. Therefore, we propose an Energy-balanced Routing protocol with Nonuniform Clustering (ERNC) to balance energy consumption and improve the data transmission efficiency. Firstly, without accurate 3D localization, nodes exchange information with each other and the combined coordinate of layer ID and hop ID is proposed to represent the node’s location information for subsequent cluster head (CH) selection and inter-cluster routing. Then, the combined coordinate, residual energy and the node density are considered comprehensively to select CHs for making the distribution of them uneven and equalizing the energy consumption. In the inter-cluster routing phase, the next hop candidate node sets with different forwarding priority are constructed based on nodes’ coordinate to improve the network transmission efficiency. Moreover, we design the different holding time for the next-hop nodes in the same set to balance the energy consumption of CHs. The simulation results show that ERNC can effectively extend the network lifetime and improve the data transmission performance.
This paper presents the implementation and analysis of a high-throughput, low-latency, reliable data collection protocol for a wireless sensor network. Insofar as reliable data collection is concerned, end-to-end packet loss recovery is demanded to improve the packet delivery ratio. Traditionally, end-to-end packet loss recovery consists of phases of connection formation and tearing down, which cause extra collection delay. To ease the burden while achieving end-to-end loss recovery, this paper makes full use of the payload of tokens and proposes to piggyback lost packets’ information on tokens to achieve end-to-end packet retransmissions. Meanwhile, high throughput can be maintained by pipelined burst data transfer and multi-channel TDMA communication. One token’s piggyback capability is limited due to the fixed available payload;
token-burst
is further used to improve piggyback capability. For token-sheduled multi-channel TDMA communication data collection in wireless sensor networks, existing research lacks quantitative analysis on the relationship between topology and collection capacity. So, quantitative analysis is conducted for the protocol primitive using mathematical induction method. The analysis result shows that regardless of the shape of tree-based routing topologies, the collection capacity difference between token-sheduled multi-channel TDMA and Optimized-TDMA is upper bound by 25%, which is verified by extensive simulations. The protocol stack is implemented on sensor nodes equipped with the CC2420 radio chip. The efficiency has been verified with 100% data collection on a deployed test bed consisting of 29 sensor nodes. In addition, extensive simulations are also conducted to investigate the protocol’s performance in a fine-grained way.
In underwater acoustic sensor networks (UASNs), the energy resources available to the underwater nodes are severely limited. The depletion of node energy can decrease network connectivity and shorten the lifetime of the network. Clustering routing has been proven to be an effective technique for improving energy efficiency and extending the lifetime of the network. Therefore, concerning the problems of non-uniform clustering, unbalanced energy consumption, and short network lifetime in existing cluster routing protocols, a fuzzy C-means clustering and improved arithmetic optimization algorithm-based layering cooperative routing (FCALCR) protocol for three-dimensional static underwater acoustic sensor networks is proposed in this paper. The FCALCR protocol introduces a fuzzy C-mean algorithm to cluster the nodes in the network, which achieves uniform clustering. Each node is configured a layer to facilitate data packets to be transmitted layer by layer to the sink, which improves the reliability of the packet transmission. Furthermore, a Sobol sequence and multi-stage dynamic perturbation strategy-based arithmetic optimization algorithm is proposed to select the best cluster head forwarding node, which accelerates the convergence speed and improves the robustness of the routing protocol. Simulation results show that the proposed FCALCR protocol outperforms the protocols of LEACH, LEACH-ERE, EGRC, FCMMFO, and EECRP in terms of network lifetime and packet transmission efficiency.
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.
The primary objective of this research is to examine the difficulties encountered in underwater acoustic Sensor Networks (UASN) due to empty spaces in acoustic route routing. The presence of empty areas inside the network often results in the unsuccessful transmission of data packets in sparsely populated underwater acoustic sensor networks (UASNs). The current techniques used to identify and circumvent empty spaces are characterized by a significant expenditure of time and a reliance on location data. To tackle this issue, the study introduces a new protocol named Secure Opportunistic Vacant Hole Avoidance Routing (SOVHAR), which aims to enhance routing pathways by disregarding vacant spaces. The proposed approach guarantees the continuous transmission of packets to the intended destination by using a local neighbourhood search strategy on sensor nodes. This strategy considers several criteria, such as node depth, signal amplitude, and the number of intermediate hops. The protocol further considers variables such as salinity, losses, and noise level to enhance the precision of the localized search for energy-efficient packet transmission. A fitness function is established to assess the efficacy of a sensor node in transmitting data packets, therefore aiding in avoiding areas with limited coverage while minimizing additional costs. The efficacy of the proposed SOVHAR is assessed via simulations, demonstrating its energy efficiency and capability to avoid empty spaces while considering different communication factors. This evaluation highlights its enhanced resilience compared to current methodologies.
Performing a high-capacity Medium Access Control (MAC) protocol suffers from low bandwidth and long propagation delay in Underwater Acoustic Networks (UANs). Non-Orthogonal Multiple Access (NOMA) is a promising technology to assist MAC protocols in overcoming the above restrictions and improving UANs’ capacity. It enables multiple users to access the same frequency-time resource based on power or code differences of user classes. However, UANs lack MAC research employing NOMA’s physical advantages. Most existing NOMA-based MAC protocols are designed for terrestrial networks, which are inapplicable to UANs. In classifying users, they ignore the effects of harsh marine environments on acoustic channels and fail to decrease channels’ interference, resulting in conflicting communications. Moreover, such unreasonable classification results further affect resource allocation, leading to low transmission rate and high energy consumption in UANs. In this paper, we propose a Hybrid NOMA-based MAC protocol (HN-MAC) to achieve efficient concurrent communication for UANs. Specifically, HN-MAC combines power-domain and code-domain NOMA to classify users and allocate communication resources. For the user classification, we propose an Adaptive Clustering Algorithm (ACA), which dynamically determines the clusters’ number and classifies users based on channel gain and channel correlation under multipath conditions. In this way, HN-MAC decreases interference among multiple users in various ocean scenarios. During the resource allocation, we formulate a joint allocation problem of transmission power and codebook based on the clustering result to optimize transmission rate and energy consumption. Further, a genetic algorithm is proposed to solve the allocation problem by considering resource constraints. Simulation results show that HN-MAC provides more stable concurrent communications with less resource consumption than the state-of-the-art protocols in various UANs.
The role of Internet of Things (IoT) in rendering the ever-growing advancements in Maritime Transportation System (MTS), is impeccable and promising. The IoT devices employed for communication for MTS are resource-constrained and can be jeopardized by unknown security attacks or threats. Hence, to pact with the energy limitation and to ensure secure communication, in this article, we propose a novel routing technique named Intelligent Internet of Things (
) for Green and secure communication in IoT-enabled MTS. In this article, we apply a suggested meta-heuristic approach called the Artificial Rabbits Optimization (ARO) for novel selection of the Cluster Head (CH). The ARO ensures the optimized selection of CH while considering various parameters namely, energy index, distance parameter, etc. Extensive experiments of the proposed approach show that
outperforms the state-of-the-art methods using a variety of performance measures as a benchmark.
conserves the energy of IoT devices employed for MTS and it also ensures the secure communication among them.
With the technological advancements, wireless sensor network (WSN) has played an impeccable role in monitoring the underwater applications. Underwater WSN (UWSN) is supported by WSN but subjected to data dissemination in an acoustic medium. Due to challenging conditions in underwater scenario, the limited battery resources of these sensor nodes stem to a crucial research problem that needs to address the energy‐efficient routing in UWSN. In this research work, we intend to propose an energy‐optimized cluster head (CH) selection based on enhanced remora optimization algorithm (ECERO) in UWSN. Since CH devours the maximum energy among the nodes, we perform selection of CH based on EROA while considering energy, Euclidean distance from sink, node density, network's average energy, acoustic path loss model and lastly, the adaptive quantity of CHs in the network. Further, to reduce the load on CH node, we introduce the concept of sleep scheduling among the closely located cluster nodes. The proposed work improves the performance of recently proposed EOCSR algorithm by great magnitude which claims to mitigate hot‐spot problem, but EOCSR still suffers from the same due to relaying a large magnitude of data.
Wireless information routing beneath the ocean, or usually underwater, has supplied the most excellent technical methods of oceanic observations. Traditionally, ocean bottoms have been monitored by placing oceanographic sensors that collect data at specific and defined ocean zones. When the duties are performed, the oceanographic instruments are recovered. Because there is no collaborative exchange of collected data between the collecting point and the monitoring end, data cannot be observed remotely. Underwater sensor networks can be wirelessly connected with sensors and monitors without extensive cable. Underwater wireless sensor networks are what they are called (UWSNs). This article investigates the various aspects of UWSNs, such as their significance, applications, network design, demands, routing, deployments and challenges.
Underwater acoustic sensor networks (UASNs) are effective instruments for monitoring marine environments and surveying seabed resources, it is important to improve their security protection, including source location privacy protection. Numerous strategies have been presented by researchers to strengthen location privacy, however, the majority of these plans have expensive energy costs. Therefore, a backbone network construction-based multi-autonomous underwater vehicle (AUV) collaboration source location privacy protection (BNCSLP) algorithm has been enhanced to address this issue. First, the nodes in the network are split into various clusters, and an entire network is segmented into various regions. The backbone network is built using clusters that house the source. To prevent the adversary’s tracking, the AUV alternately chooses alternative backbone nodes and relays the source and fake data. Then, the cluster head determines whether to update the clusters by calculating how similar the data are with nearby clusters. The nearest neighbor technique is used by the updated cluster to anticipate the data and to reduce the energy utilization of forwarding the data packets, resulting in that there is less chance of data packets being intercepted and the source location being revealed. Finally, the AUV re-plans the trajectory, which shortens the AUV’s travelling path because only fewer cluster heads need to be accessed, decreasing the time it takes for data to be transmitted.
Underwater acoustic sensor networks, which are popular in various application fields, including marine resources development, environmental exploration, seismic monitoring, etc., have made great progress in recent years. To maintain good scheduling performance, clustering algorithms and MAC protocols have been widely used in sensor networks to improve network efficiency. However, the existing algorithms and protocols still have many shortcomings. For example, many clustering algorithms consider the delay performance little, the cluster structures are not always fully utilized by MAC protocols, and the cluster maintenance strategies are not considered. This paper is devoted to solving those problems. By taking the node traffics and distances into account simultaneously, we design the cluster structure reasonably. And based on this structure, we plan a conflict-free handshake protocol with minimal idle time gaps. Besides, we also design a joining-cluster strategy for the free nodes to maintain the network without interference. Simulation results show that our work can perform well in network uniformity and end-to-end delay.
Underwater acoustic communication networks (UACNs) have been widely utilized in recent years because of the growing interest in interactive information in the deep ocean. Compared with traditional radio wireless networks, UACNs are characterized by complex and dynamic three-dimensional network topology and longer signal propagation delay. Therefore, recent studies on UACNs usually apply dynamic routes in data communication to adapt to complex UACN structure. However, the approaches are hardly adequate for UACN scenarios with high-traffic requirements. This is because dynamic routing methods, such as opportunistic routing, usually require external contention costs to control the routing paths, which leads to decreased network throughput. Accordingly, this paper focuses on enabling high-speed acoustic communications for underwater application scenarios with high-traffic requirements, and proposes an underwater data transmission method using the multi-channel full-duplex (FD) communication technique. The proposed method applies the underwater orthogonal frequency division multiple access (OFDM) technique, that uses collision-free channels to relay data in multi-hop routes for simultaneous transmission and reception. Unlike the traditional communication methods of UACNs with dynamic routing, the proposed one uses static routes when transporting data over hop-by-hop paths to achieve stable and uninterrupted FD communication. The approach also includes a directional-forwarding based route request method and an elimination-based channel evaluation proposal, which purpose to reduce the overheads from exploring routes and enable collision-free FD communications. The performance analysis of the proposed method is under simulated conditions of high-traffic UACN scenarios, and the results show that it has superior performance compare to the classical underwater data transmission methods.
Underwater communication is a diverse and complex environment and has many problems. There are many problems in modeling and operating underwater networks. Physical and data link layer specifications for underwater networking should be taken into account in terms of quality of service metrics. In this study, we construct an underwater simulation environment as a cross-layer design consisting of physical and data link layers for the Internet of Underwater Things (IoUT) Network. The IoUT network has sensors with various priorities, a central node as a hub and a gateway as a buoy. The underwater sensors communicate with CSMA/CA-based IEEE 802.15.6 protocol on low frequencies. For a more realistic communication channel, all the features of the acoustic channel are designed and performance analyzes are discussed. In addition, the proposed IoUT is compared with terrestrial network results in terms of bit error rate, signal-to-noise ratio, packet loss ratio, end-to-end delay, radio receiver utilization, and throughput. We claim that we have made a realistic IoUT network, especially for divers, autonomous underwater vehicles with specific sensors, or for similar purposes.
Underwater wireless sensor networks (UWSNs) have applications in several fields, such as disaster management, underwater navigation, and environment monitoring. Since the nodes in UWSNs are restricted to inbuilt batteries, the effective utilization of available energy becomes essential. Clustering and routing approaches can be employed as energy-efficient solutions for UWSNs. However, the cluster-based routing techniques developed for conventional wireless networks cannot be employed for a UWSN because of the low bandwidth, spread stay, underwater current, and error probability. To resolve these issues, this article introduces a novel chaotic search-and-rescue-optimization-based multi-hop data transmission (CSRO-MHDT) protocol for UWSNs. When using the CSRO-MHDT technique, cluster headers (CHs) are selected and clusters are prearranged, rendering a range of features, including remaining energy, intracluster distance, and intercluster detachment. Additionally, the chaotic search and rescue optimization (CSRO) algorithm is discussed, which is created by incorporating chaotic notions into the classic search and rescue optimization (SRO) algorithm. In addition, the CSRO-MHDT approach calculates a fitness function that takes residual energy, distance, and node degree into account, among other factors. A distinctive aspect of the paper is demonstrated by the development of the CSRO algorithm for route optimization, which was developed in-house. To validate the success of the CSRO-MHDT method, a sequence of tests were carried out, and the results showed the CSRO-MHDT method to have a packet delivery ratio (PDR) of 88%, whereas the energy-efficient clustering routing protocol (EECRP), the fuzzy C-means and moth–flame optimization (FCMMFO), the fuzzy scheme and particle swarm optimization (FBCPSO), the energy-efficient grid routing based on 3D cubes (EGRC), and the low-energy adaptive clustering hierarchy based on expected residual energy (LEACH-ERE) methods have reached lesser PDRs of 83%, 81%, 78%, 77%, and 75%, respectively, for 1000 rounds. The CSRO-MHDT technique resulted in higher values of number of packets received (NPR) under all rounds. For instance, with 50 rounds, the CSRO-MHDT technique attained a higher NPR of 3792%.
The particularity of the marine underwater environment has brought many challenges to the development of underwater sensor networks (UWSNs). This research realized the effective monitoring of targets by UWSNs and achieve higher quality of service in various applications such as communication, monitoring, and data transmission in the marine environment. After analysis of the architecture, the marine integrated communication network system (MICN system) is constructed based on the maritime wireless Mesh network (MWMN) by combining with the UWSNs. A distributed hybrid fish swarm optimization algorithm (FSOA) based on mobility of underwater environment and artificial fish swarm (AFS) theory is proposed in response to the actual needs of UWSNs. The proposed FSOA algorithm makes full use of the perceptual communication of sensor node and let the sensor nodes share the information covered by each other as much as possible, enhancing the global search ability. In addition, a reliable transmission protocol NC-HARQ is put forward based on the combination of network coding (NC) and hybrid automatic repeat request (HARQ). In this work, three sets of experiments are performed in an area of 200 × 200 × 200 m. The simulation results show that the FSOA algorithm can fully cover the events, effectively avoid the blind movement of nodes, and ensure consistent distribution density of nodes and events. The NC-HARQ protocol proposed uses relay nodes for retransmission, and the probability of successful retransmission is much higher than that of the source node. At a distance of more than 2000 m, the successful delivery rate of data packets is as high as 99.6%. Based on the MICN system, the intelligent ship constructed with the digital twins framework can provide effective ship operating state prediction information. In summary, this study is of great value for improving the overall performance of UWSNs and advancing the monitoring of marine data information.
Underwater wireless sensor networks (UWSNs) comprise numerous underwater wireless sensor nodes dispersed in the marine environment, which find applicability in several areas like data collection, navigation, resource investigation, surveillance, and disaster prediction. Because of the usage of restricted battery capacity and the difficulty in replacing or charging the inbuilt batteries, energy efficiency becomes a challenging issue in the design of UWSN. Earlier studies reported that clustering and routing are considered effective ways of attaining energy efficacy in the UWSN. Clustering and routing processes can be treated as nondeterministic polynomial-time (NP) hard optimization problems, and they can be addressed by the use of metaheuristics. This study introduces an improved metaheuristics-based clustering with multihop routing protocol for underwater wireless sensor networks, named the IMCMR-UWSN technique. The major aim of the IMCMR-UWSN technique is to choose cluster heads (CHs) and optimal routes to a destination. The IMCMR-UWSN technique incorporates two major processes, namely the chaotic krill head algorithm (CKHA)-based clustering and self-adaptive glow worm swarm optimization algorithm (SA-GSO)-based multihop routing. The CKHA technique selects CHs and organizes clusters based on different parameters such as residual energy, intra-cluster distance, and inter-cluster distance. Similarly, the SA-GSO algorithm derives a fitness function involving four parameters, namely residual energy, delay, distance, and trust. Utilization of the IMCMR-UWSN technique helps to significantly boost the energy efficiency and lifetime of the UWSN. To ensure the improved performance of the IMCMR-UWSN technique, a series of simulations were carried out, and the comparative results reported the supremacy of the IMCMR-UWSN technique in terms of different measures.
The current Internet of Underwater Things (IoUT) for marine observations and emergency responses suffer from two critical issues: energy-efficient and timely data collection. Autonomous underwater vehicles (AUVs), serving as tools for collecting and forwarding distributed data, can deal with the unbalanced power consumption in traditional multihop underwater communication network. However, the low speed of the AUV has not been able to guarantee timeliness of delay-sensitive data. In this paper, 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 firstly 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.
Constrained-energy underwater acoustic nodes are typically connected via a multi-hop underwater acoustic network (MHUAN) to cover a broad marine region. Recently, protocols for efficiently connecting such nodes have received considerable attention. In this paper, we show that the time reversal (TR) process plays an important role in the medium access control (MAC) because of its physical capability to exploit the multi-path energy from the richly scattering underwater environment, as well as to focus the signal energy in both spatial and temporal domains. In MHUANs, with severe multi-path propagation at the physical layer, the active TR process spatially focuses the signals to the location of the intended receiver; this significantly diminishes the interference among parallel links. We propose an active TR-based MAC (TRMAC) protocol for MHUANs, with the aim of minimizing collision and maximizing channel utilization simultaneously. Furthermore, by considering the impact of the cross correlation between different links on the TR-based medium access, we derive the threshold of the link cross correlation to resolve collision caused by the high cross correlation between realistic links. We perform simulations using the OPNET and BELLHOP environments, and show that the proposed TRMAC results in significantly improved throughput, decreased delay, and reduced data drop ratio in MHUANs.
Interference and energy holes formation in underwater wireless sensor networks (UWSNs) threaten the reliable delivery of data packets from a source to a destination. Interference also causes inefficient utilization of the limited battery power of the sensor nodes in that more power is consumed in the retransmission of the lost packets. Energy holes are dead nodes close to the surface of water, and their early death interrupts data delivery even when the network has live nodes. This paper proposes a localization-free interference and energy holes minimization (LF-IEHM) routing protocol for UWSNs. The proposed algorithm overcomes interference during data packet forwarding by defining a unique packet holding time for every sensor node. The energy holes formation is mitigated by a variable transmission range of the sensor nodes. As compared to the conventional routing protocols, the proposed protocol does not require the localization information of the sensor nodes, which is cumbersome and difficult to obtain, as nodes change their positions with water currents. Simulation results show superior performance of the proposed scheme in terms of packets received at the final destination and end-to-end delay.
With a wide scope to explore and harness the oceanic sources of interest, the field of underwater wireless sensor networks (UWSN) is attracting a growing interest of researchers. Owing to the real-time remote data monitoring requirements, underwater acoustic sensor networks (UASN) emerged as a preferred network to a great extent. In UASN, the limited availability and non-rechargeability of energy resources along with the relative inaccessibility of deployed sensor nodes for energy replenishments necessitated the evolution of several energy optimization techniques. Clustering is one such technique that increases system scalability and reduces energy consumption. Besides clustering, coverage and connectivity are two significant properties that decide the proper detection and communication of events of interest in UWSN due to unstable underwater environment. Underwater communication is also possible with non-acoustic communication techniques like radio frequency (RF), magnetic induction (MI) and underwater free-space optics (UWFSO). In this paper, we surveyed clustering, coverage and connectivity issues of UASN and qualitatively compared their performance. Particularly, the impact of these non-conventional communication techniques on clustering, coverage and connectivity aspects is demonstrated. Additionally, we highlighted some key open issues related to the UWSN. This paper provides a broad view of existing algorithms of clustering, coverage and connectivity based on acoustic communication. It also provides a useful guidance to the researchers in UWSN from various other communication techniques perspective.
Underwater wireless sensor networks (UWSNs) have been showed as a promising technology to monitor and explore the oceans in lieu of traditional undersea wireline instruments. Nevertheless, the data gathering of UWSNs is still severely limited because of the acoustic channel communication characteristics. One way to improve the data collection in UWSNs is through the design of routing protocols considering the unique characteristics of the underwater acoustic communication and the highly dynamic network topology. In this paper, we propose the GEDAR routing protocol for UWSNs. GEDAR is an anycast, geographic and opportunistic routing protocol that routes data packets from sensor nodes to multiple sonobuoys (sinks) at the sea's surface. When the node is in a communication void region, GEDAR switches to the recovery mode procedure which is based on topology control through the depth adjustment of the void nodes, instead of the traditional approaches using control messages to discover and maintain routing paths along void regions. Simulation results show that GEDAR significantly improves the network performance when compared with the baseline solutions, even in hard and difficult mobile scenarios of very sparse and very dense networks and for high network traffic loads.
Sensor Network (WSN) localization is an important and fundamental problem that has received a lot of attention from the WSN research community. Determining the absolute and relative coordinate of sensor nodes in the network adds much more meaning to sense data. The research community is very rich in proposals to address this challenge in WSN. This paper, explores the various techniques proposed to address the acquisition of location information in WSN. The paper also evaluate the performance of these techniques based on the energy consumption, the skill and man hours needed to implement the technique and localization accuracy (error rate) and discuss some open issues for future research. Keywordssensor network, sensor nodes, localization centralized and distributed algorithm, range-based and range- free algorithm.
The WKB method has been used to develop an approximate solutionof the semi-geostrophic Ekman boundary layer with height-dependenteddy viscosity and a baroclinic pressure field. The approximate solutionretains the same simple form as the classical Ekman solution. Behavioursof the approximate solution are discussed for different eddy viscosityand the pressure systems. These features show that wind structure inthe semi-geostrophic Ekman boundary layer depends on the interactionbetween the inertial acceleration, variable eddy viscosity and baroclinicpressure gradient. Anticyclonic shear has an acceleration effect on theair motion in the boundary layer, while cyclonic shear has a decelerationeffect. Decreasing pressure gradient with height results in a super-geostrophicpeak in the wind speed profile, however the increasing pressure gradient withheight may remove the peak. Anticyclonic shear and decreasing the variableeddy viscosity with height has an enhanced effect on the peak.
Variable eddy viscosity and inertial acceleration has an important role in thedivergence and vorticity in the boundary layer and the vertical motion at the top of the boundary layer that is called Ekman pumping. Compared to the constanteddy viscosity case, the variable eddy diffusivity reduces the absolute value ofEkman pumping, especially in the case of eddy viscosity initially increasing with height. The difference in the Ekman pumping produced by different eddy diffusivity assumptions is intensified in anticyclonic flow and reduced in cyclonic flow.
This paper investigates a fundamental networking problem in underwater sensor networks: robust and energy-efficient routing. We present an adaptive location-based routing protocol, called hop-by-hop vector-based forwarding (HH-VBF). It uses the notion of a "routing vector" (a vector from the source to the sink) acting as the axis of the "routing pipe", similar to the vector based forward (VBF) routing in the work of P. Xie, J.-H. Cui and L. Lao (VBF: Vector-Based Forwarding Protocol for Underwater Sensor Networks. Technical report, UCONN CSE Technical Report: UbiNet-TR05-03 (BECAT/CSE-TR-05-6), Feb. 2005). Unlike the original VBF approach, however, HH-VBF suggests the use of a routing vector for each individual forwarder in the network, instead of a single network-wide source-to-sink routing vector. By the creation of the hop-by-hop vectors, HH-VBF can overcome two major problems in VBF: (1) too small data delivery ratio for sparse networks; (2) too sensitive to "routing pipe" radius threshold. We conduct simulations to evaluate HH-VBF, and the results show that HH-VBF yields much better performance than VBF in sparse networks. In addition, HH-VBF is less sensitive to the routing pipe radius threshold. Furthermore, we also analyze the behavior of HH-VBF and show that assuming proper redundancy and feedback techniques, HH-VBF can facilitate the avoidance of any "void" areas in the network.
In this paper, we propose the Staggered TDMA Underwater MAC Protocol (STUMP), a scheduled, collision free TDMA-based MAC protocol that leverages node position diversity and the low propagation speed of the underwater channel. STUMP uses propagation delay information to overlap node communication and increase channel utilization. Our work yields several important conclusions. First, leveraging node position diversity through scheduling yields large improvements in channel utilization. Second, STUMP does not require tight node synchronization to achieve high channel utilization, allowing nodes to use simple or more energy efficient synchronization protocols. Finally, we briefly present and evaluate algorithms that derive STUMP schedules.
Designing of media access control (MAC) protocol is one of the major challenges in underwater acoustic sensor networks. Because of the long and changeful propagation delay, MAC protocols for traditional terrestrial sensor networks are unavailable. We propose a TDMA-based approach which is easy to dispose and energy-efficient. In brief, our MAC protocol includes the lightweight synchronization designed to suit to underwater environments, the defer time to allocate transmitting time of all nodes, the guard time to avoid collision with the sleep strategy to save energy. Simulation results show our MAC protocol feasible and efficient, especially in the high traffic load cases.
Underwater sensor nodes will find applications in oceanographic data collection, pollution monitoring, offshore exploration, disaster prevention, assisted navigation and tactical surveillance applications. Moreover, unmanned or autonomous underwater vehicles (UUVs, AUVs), equipped with sensors, will enable the exploration of natural undersea resources and gathering of scientific data in collaborative monitoring missions. Underwater acoustic networking is the enabling technology for these applications. Underwater networks consist of a variable number of sensors and vehicles that are deployed to perform collaborative monitoring tasks over a given area.In this paper, several fundamental key aspects of underwater acoustic communications are investigated. Different architectures for two-dimensional and three-dimensional underwater sensor networks are discussed, and the characteristics of the underwater channel are detailed. The main challenges for the development of efficient networking solutions posed by the underwater environment are detailed and a cross-layer approach to the integration of all communication functionalities is suggested. Furthermore, open research issues are discussed and possible solution approaches are outlined.
In this paper we present a novel platform for underwater sen-sor networks to be used for long-term monitoring of coral reefs and fisheries. The sensor network consists of static and mobile underwater sensor nodes. The nodes commu-nicate point-to-point using a novel high-speed optical com-munication system integrated into the TinyOS stack, and they broadcast using an acoustic protocol integrated in the TinyOS stack. The nodes have a variety of sensing capa-bilities, including cameras, water temperature, and pres-sure. The mobile nodes can locate and hover above the static nodes for data muling, and they can perform network maintenance functions such as deployment, relocation, and recovery. In this paper we describe the hardware and soft-ware architecture of this underwater sensor network. We then describe the optical and acoustic networking protocols and present experimental networking and data collected in a pool, in rivers, and in the ocean. Finally, we describe our experiments with mobility for data muling in this network.
Underwater sensor networks are attracting increasing in-terest from researchers in terrestrial radio-based sensor net-works. There are important physical, technological, and eco-nomic di erences between terrestrial and underwater sensor networks. Previous surveys have provided thorough back-ground material in underwater communications, and an in-troduction to underwater networks. This has included detail on the physical characteristics of the channel [1], on under-water acoustic communications [2, 3, 4], and surveys of un-derwater acoustic networks [5, 6, 7, 8]. In this survey, we highlight a number of important practical issues that are not emphasized in the recent surveys of underwater networks, with an intended audience of researchers who are moving from radio-based terrestrial networks into underwater net-works. We focus on issues relevant to medium access control (MAC) protocols, which are an area of continuing work both
Due to harsh aqueous environments, non-negligible node mobility and large network scale, localization for large-scale mobile underwater sensor networks is very challenging. In this paper, by utilizing the predictable mobility patterns of underwater objects, we propose a scheme, called Scalable Localization scheme with Mobility Prediction (SLMP), for underwater sensor networks. In SLMP, localization is performed in a hierarchical way, and the whole localization process is divided into two parts: anchor node localization and ordinary node localization. During the localization process, every node predicts its future mobility pattern according to its past known location information, and it can estimate its future location based on the predicted mobility pattern. Anchor nodes with known locations in the network will control the localization process in order to balance the trade-off between localization accuracy, localization coverage, and communication cost. We conduct extensive simulations, and our results show that SLMP can greatly reduce localization communication cost while maintaining relatively high localization coverage and localization accuracy.
TDMA protocols have attracted a lot of attention for underwater acoustic sensor networks (UWSNs), because of the unique characteristics of acoustic signal propagation such as great energy consumption in transmission, long propagation delay and long communication range. Previous TDMA protocols all allocated transmission time to nodes based on discrete time slots. This paper proposes an efficient continuous time scheduling TDMA protocol (ECS) for UWSNs, including the continuous time based and sender oriented conflict analysis model, the transmission moment allocation algorithm and the distributed topology maintenance algorithm. Simulation results confirm that ECS improves network throughput by 20% on average, compared to existing MAC protocols.
This paper examines the main approaches and challenges in the design and implementation of underwater wireless sensor networks. We summarize key applications and the main phenomena related to acoustic propagation, and discuss how they affect the design and operation of communication systems and networking protocols at various layers. We also provide an overview of communications hardware, testbeds and simulation tools available to the research community.
The advent of underwater acoustic sensor networks (UASNs) has enhanced marine environmental monitoring, auxiliary navigation, and marine military defense. One of the core functions of UASNs is data collection. However, current underwater data collection schemes generally encounter problems such as high energy consumption and high latency. Furthermore, the application of multiple autonomous underwater vehicles (AUVs) has contributed to more problems of task assignment and load balancing. This leads to significant failure in data collections and controlling of spontaneous emergencies. To address these problems, a district partition based data collection algorithm with event dynamic competition in UASNs has been proposed. In this algorithm, the value of information (VoI) of the packet determines the priority of its transmission to the cluster head. The navigation position of the mobile sink and the area under the responsibility of each AUV are determined by the spatial region division. The path of the AUV in the subregion is then planned using reinforcement learning. Subsequently, the dynamic competition of multiple AUVs is used to handle emergency tasks. The simulation demonstrates that our proposed algorithm significantly reduces energy consumption to guarantee load balancing while reducing end-to-end transmission delay.
In this paper, an autonomous underwater vehicle (AUV) location prediction-based data collection scheme (ALP) has been proposed, to overcome high and unbalanced energy consumption for underwater wireless sensor networks (UWSNs). In our scheme, an AUV travels around the network, follows a predefined trajectory, and collects data from the sensor nodes. The nodes near the trajectory send their data to the AUV directly while the others send data to their neighbors that are closer to the trajectory. To overcome the “hot region” problem that means the nodes near the trajectory of the AUV to consume energy faster and die early, a trajectory adjustment mechanism is applied. A mathematical model is proposed to adjusted the trajectory periodically. To guarantee an efficient communication between the nodes and the AUV, a reliable time mechanism is proposed. In this mechanism, only the nodes with a sufficient amount of time are capable to communicate and send their data to the AUV directly. The analyses and simulation results validate that our proposed ALP prolongs the network lifetime and has a higher packet delivery ratio than the existing protocols.
In this paper, a high-availability data collection scheme based on multiple autonomous underwater vehicles (AUVs) (HAMA) is proposed to improve the performance of the sensor network and guarantee the high availability of the data collection service. Multi-AUVs move in the network and their trajectory is pre-defined. Data from the nodes near the trajectory of an AUV are sent to the AUV directly and the other nodes transmit their data to the nodes that are closer to the trajectory. A malfunction discovery and repair mechanisms are applied to ensure that the network operates appropriately when an AUV fails to communicate with the nodes while collecting data. Compared with existing methods, the HAMA method increases the packet delivery ratio and the network lifetime
Underwater acoustic sensor networks (UASNs) are widely used in a variety of ocean applications, such as exploring ocean resources or monitoring abnormal ocean environments. However, data collection schemes in UASNs are significantly different than those in wireless sensor networks due to high power consumption, high propagation delay, and so on. What's more, previous research has overlooked practical conditions, such as water delamination characteristics and autonomous underwater vehicles (AUV) limited energy. To solve these problems, we propose a data collection scheme based on a stratification model (DCSM) for 3D UASNs. In our scheme, the network is divided into two layers. The top layer, called the Ekman layer, is dynamic; we employ a forwarding set-based multi-hop forwarding algorithm in data collection. Then, a neighbor density clustering-based AUV data gathering algorithm is adopted in the second layer, which is relatively static. By employing different data collection algorithms in different layers, we can integrate the advantages of a multi-hop transmission scheme and AUV-aided data collection scheme to reduce network consumption and improve network lifetime. The simulation results also confirm the proposed method has good performance. IEEE
With the rapid proliferation of mobile wireless sensors networks (WSN), which are widely deployed in the Internet of things (IoT), the Internet of vehicles (IoV) and flying ad hoc networks (FANET), more and more researchers are attracted to make efforts on improving energy efficiency and throughput of WSN. In recent years, lots of protocols are proposed to solve the energy shortage problem. Some of the protocols are based on cooperative or allocation scheme, some are based on contending scheme, and others are on the foundation of hybrid scheme. However, it is still difficult to improve the energy efficiency and networks throughput simultaneously. In this paper, we present a novel CSMA/CA and TDMA hybrid scheme protocol (CTh-MAC) on MAC layer to improve the throughput and reduce energy consumption at the same time for mobile WSN with position prediction algorithm. Comparing to existing protocols, the proposed protocol can efficiently reduce the energy consumption and significantly improve the throughput, especially for high-speed mobile WSN in many-to-one communication paradigm. Extensive simulation results prove the performance of the protocol.
Interference-aware routing protocol design for underwater wireless sensor networks (UWSNs) is one of the key strategies in reducing packet loss in the highly hostile underwater environment. The reduced interference causes efficient utilization of the limited battery power of the sensor nodes that, in consequence, prolongs the entire network lifetime. In this paper, we propose an energy-efficient interference-aware routing (EEIAR) protocol for UWSNs. A sender node selects the best relay node in its neighborhood with the lowest depth and the least number of neighbors. Combination of the two routing metrics ensures that data packets are forwarded along the least interference paths to reach the final destination. The proposed work is unique in that it does not require the full dimensional localization information of sensor nodes and the network total depth is segmented to identify source, relay and neighbor nodes. Simulation results reveal better performance of the scheme than the counterparts DBR and EEDBR techniques in terms of energy efficiency, packet delivery ratio and end-to-end delay.
Most applications of underwater acoustic sensor networks (UASNs) rely upon reliable location information of sensor nodes. However, the harsh underwater environment makes localization more challenging as compared to terrestrial sensor networks. This paper is concerned with a localization issue for UASNs, subject to clock asynchronization and node mobility. A hybrid architecture including autonomous underwater vehicles (AUVs), active and passive sensor nodes is designed, where AUVs act as anchor nodes to provide localization information for sensor nodes. In order to eliminate the effect of asynchronous clocks and compensate the mobility of sensor nodes, an asynchronous localization algorithm with mobility prediction is provided for active and passive sensor nodes. Then, two localization optimization problems are formulated as minimizing the sum of all measurement errors. To solve the localization optimization problems, iterative least squares estimators are designed. In addition, the convergence analysis and Cramér-Rao lower bound for the localization errors are also provided. Finally, simulation results show that the proposed localization approach can reduce the localization time by comparing with the exhaustive search-based localization method. Meanwhile, the asynchronous algorithm in this paper can effectively eliminate the impact of the clock asynchronization and node mobility.
In Underwater Wireless Sensor Networks (UWSN), the existing scheduling technique causes propagation delay or overhead issue. Also the data collision is likely to occur. In order to overcome this issue, in this paper, we propose to design a cluster-based MAC protocol for collision avoidance and TDMA scheduling in UWSN. Initially, the clusters are formed and cluster heads (CHs) are elected as per the energy-efficient hierarchical clustering algorithm. The cluster members, which are one-hop neighbors of CH, schedule the data sending times for all cluster members. The energy consumption analytical model is derived to show the average energy consumed by each CH. Finally, conflict-free scheduling is performed by using Spatial-Temporal-Confliction-Table. This allows nodes to transmit at the same time as long as their packets arrive during different times at the intended destinations. Simulation results show that the proposed MAC protocol reduces the delay and energy consumption while by increasing the packet delivery ratio.
Localization problem in mobile wireless sensor networks has drawn widely attention in recent years due to the rapid advances in mobile computing and improvements of wireless communication technologies. Indeed, mobile sensor networks become a valuable asset for many applications, since sensors can be mobile or easily tethered to mobile entities such as robots, vehicles or human. Thereby, it is crucial to support mobility without compromising the quality of applications that require wireless communications. Although, numerous research activities have successfully addressed the localization problem in static networks, few studies deal with the localization issue in mobile sensor networks. In this paper, we present a survey on existing work in this area and we address the gaps for actual deployment of mobile wireless sensor networks. Following our analysis, we propose a classification of the most important algorithms and schemes that outcome from recent literature. We discuss their basic principles, characteristics and concepts. Finally, we point out open research issues, their challenges and some future directions for localization in mobile wireless sensor networks.
In this paper, we propose a reliable and interference-aware routing protocol for underwater wireless sensor networks (UWSNs). Proposed protocol follows end-to-end path from source node to sink and selects next forwarder node of a data packet on the basis, having already established a path to sink. In this way, the problem of encounters void hole in depth based routing protocol is eliminated. Furthermore, during the selection of forwarding node, channel interference is also considered as routing metric to provide reliable communication. Therefore, proposed scheme reduces the probability of collision at the network layer, by selecting a neighbor node as the next forwarder of the data packet from the source node to the destination where the chance of channel interference is minimum. Simulation results verify the effectiveness of the proposed scheme in term of energy consumption, end-to-end delay and packet delivery ratio especially in a sparse network.
Recently, underwater wireless sensor networks (UWSNs) have emerged as a promising networking technique for various underwater applications. An energy efficient routing protocol plays a vital role in data transmission and practical applications. However, due to the specific characteristics of UWSNs, such as dynamic structure, narrow bandwidth, rapid energy consumption, and high latency, it is difficult to build routing protocols for UWSNs. In this article we focus on surveying existing routing protocols in UWSNs. First, we classify existing routing protocols into two categories based on a route decision maker. Then the performance of existing routing protocols is compared in detail. Furthermore, future research issues of routing protocols in UWSNs are carefully analyzed.
Unlike terrestrial networks that mainly rely on radio waves for communications, underwater networks utilize acoustic waves, which have comparatively lower loss and longer range in underwater environments. However, acoustic waves incurs long propagation delays that typically lead to low throughput especially in protocols that require receiver feedback such as multimedia stream delivery. In addition, energy cost of transmission underwater is much higher than reception (almost 125:1 [1]). Thus, collision and retransmission should be reduced in order to reduce energy cost and improve throughput Receiver-based protocols, like RIPT and COS-TS, can significantly reduce collision and retransmission. But they are time and energy consuming because nodes are controlled to turn into receiver mode by control packets or a timer regardless of load. In this paper, we propose an underwater practical MAC protocol, called UPMAC. The main objective of UPMAC is to adapt to the network load conditions by providing two modes (high and low load modes) and switching between them based on different offered load. Turn-around time overhead is reduced and it is less vulnerable to control packet corruption, since we reduce the use of control packets by the technique of piggyback. UPMAC provides a low data collision rate in both one-hop and multi-hop situation because we use Receiver-based approach in high load mode. Extensive simulations show that our approach can achieve significantly better performance in both general and Sea Swarm (tree) topologies.
Many researcher has paid their to explore and monitor the under water environment. There are lot of application of Underwater WSNs like environment monitoring, exploration of under water surfaces, disaster preventions assisted navigation etc. Underwater sensors are totally different from the terrestrial sensors. Terrestrial sensor network uses the radio signal and underwater sensor network uses the acoustic signal. As the radio signal has not good strength that it can propagate in the water. The Radio signal can propagate over the large distance as compared to the acoustic signals. Therefor, acoustic signal are used. In this paper, we propose Energy Hole Repairing Depth based routing protocol (EHRDBR) and Interference-Bandwidth aware Depth based routing (IBDBR) protocol. In both protocols, nodes move toward the specific area where the other node dies and cover the energy hole. In EHRDBR, forwarder node is selected on the basis of the interference residual energy, and depth parameters. In IBDBR, interference, bandwidth, residual energy, and depth parameters are used to select the forward node. Our protocols have performed better in network lifetime, throughput and ene to end delay .
The unique characteristics of Underwater Wireless Sensor Networks (UWSNs) attracted the research community to explore different aspects of these networks. Routing is one of the most important and challenging function in UWSNs, for efficient data communication and longevity of sensor node's battery timing. Sensor nodes have energy constraint because replacing the batteries of sensor nodes is an expensive and tough task in harsh aqueous environment. Also interference is a major performance influencing factor. Providing solutions for interference-free communication are also essential. In this paper, we propose three energy-efficient and interference-aware routing protocols named as Inverse Energy Efficient Depth-Based Routing protocol (IEEDBR), Interference-Aware Energy Efficient Depth-Based Routing protocol (IA-EEDBR) and Interference-Aware Inverse Energy Efficient Depth-Based Routing protocol (IA-IEEDBR). Unlike EEDBR, IEEDBR protocol uses depth and minimum residual energy information for selecting data for-warder. While IA-EEDBR takes minimum number of neighbors for forwarder selection. IA-IEEDBR considers depth, minimum residual energy along with minimum number of neighbors for selection of forwarder. Our proposed schemes are validated through simulation and the results demonstrate better performance in terms of improved network lifetime, maximized throughput and reduced path loss.
Underwater Wireless Sensor Networks (UWSNs) are expected to support a variety of civilian and military applications. In UWSNs, Medium Access Control (MAC) protocol has attracted strong attention due to its potentially large impact to the overall network performance. Unlike terrestrial networks, which mainly rely on radio waves for communications, UWSNs utilize acoustic waves, which pose a new research challenge in the design of MAC protocols. To present the development of MAC protocols in UWSNs, this paper surveys the current state-of-the-art MAC protocols for UWSNs. In the early development, the performance in terms of delay and throughput of the UWSNs has been the major concern of the MAC layer protocol design. Later, the design of energy-efficient MAC protocols becomes a new research focus because sensor nodes are generally powered by batteries which are less likely to be recharged. In this paper, we first describe the underwater acoustic environment and the challenges to the MAC protocols design in UWSNs. We then provide a comparative study of several types of MAC protocols according to current existing diverse implementations. Furthermore, open research issues will be summarized. Hopefully, this survey will inspire more active research in this area.
Geographic routing is an attractive option for large scale wireless sensor networks (WSNs) because of its low overhead and energy expenditure, but is inefficient in realistic localization conditions. Positioning systems are inevitably imprecise because of inexact range measurements and location errors lead to poor performance of geographic routing in terms of packet delivery ratio (PDR) and energy efficiency. This paper proposes a novel, low-complexity, error-resilient geographic routing method, named conditioned mean square error ratio (CMSER) routing, intended to efficiently make use of existing network information and to successfully route packets when localization is inaccurate. Next hop selection is based on the largest distance to destination (minimizing the number of forwarding hops) and on the smallest estimated error figure associated with the measured neighbor coordinates. It is found that CMSER outperforms other basic greedy forwarding techniques employed by algorithms such as most forward within range (MFR), maximum expectation progress (MEP) and least expected distance (LED). Simulation results show that the throughput for CMSER is higher than for other methods, additionally it also reduces the energy wasted on lost packets by keeping their routing paths short.
The WKB method is used in conjunction with the variation of parameters technique to find an approximate analytical solution for Ekman layers with eddy viscosity and horizontal pressure gradient that are each variable with height from the surface. Behaviour of the solution is illustrated by comparing model output when several eddy viscosity and horizontal pressure gradient profiles are used. Cases where the pressure gradient decreases with height accentuate the super-geostrophic peak in the wind velocity profile, with decreasing eddy viscosity with height further enhancing this effect. Increasing pressure gradient with height reduces or eliminates the peak. The model output when using an eddy viscosity that has a low-level peak fits marine boundary-layer data taken during ASTEX better than the classic solution - the model giving greater low-level mixing which is seen in ASTEX data as well as in data from ERICA.
Recently, Underwater Wireless Sensor Networks (UWSNs) have attracted much research attention from both academia and industry,
in order to explore the vast underwater environment. However, designing network protocols is challenging in UWSNs since UWSNs
have peculiar characteristics of large propagation delay, high error rate, low bandwidth and limited energy. In UWSNs, improving
the energy efficiency is one of the most important issues since the replacement of the batteries of such nodes is very expensive
due to harsh underwater environment. Hence, in this paper, we propose an energy efficient routing protocol, named EEDBR (Energy-Efficient
Depth Based Routing protocol) for UWSNs. Our proposed protocol utilizes the depth of the sensor nodes for forwarding the data
packets. Furthermore, the residual energy of the sensor nodes is also taken into account in order to improve the network life-time.
Based on the comprehensive simulation using NS2, we observe that our proposed routing protocol contributes to the performance
improvements in terms of the network lifetime, energy consumption and end-to-end delay.
KeywordsUnderwater wireless sensor networks–routing–network life-time–residual energy
The eddy viscosity is a fourth-order tensor in three-dimensional space. When considering the viscous effects on the horizontal
velocities in the vertical direction it is reduced to a second-order tensor in two-dimensional space, and is not necessarily
horizontally isotropic. Anisotropic coherent structures (rolls) are a conspicuous feature of the planetary boundary layer.
There is no reason to suppose that they should give rise to a horizontally isotropic eddy viscosity. The effects of an anisotropic
constant eddy viscosity tensor on the Ekman layer dynamics is determined analytically. The shape of the Ekman spiral is modified.
The magnitude of the bottom shear and the Ekman transport is changed in magnitude and rotated within an angle of 90°.
KeywordsEddy viscosity-Ekman spiral
Acoustic propagation is characterized by three major factors: attenuation that increases with signal frequency, time-varying multipath propagation, and low speed of sound (1500 m/s). The background noise, although often characterized as Gaussian, is not white, but has a decaying power spectral density. The channel capacity depends on the distance, and may be extremely limited. Because acoustic propagation is best supported at low frequencies, although the total available bandwidth may be low, an acoustic communication system is inherently wideband in the sense that the bandwidth is not negligible with respect to its center frequency. The channel can have a sparse impulse response, where each physical path acts as a time-varying low-pass filter, and motion introduces additional Doppler spreading and shifting. Surface waves, internal turbulence, fluctuations in the sound speed, and other small-scale phenomena contribute to random signal variations. At this time, there are no standardized models for the acoustic channel fading, and experimental measurements are often made to assess the statistical properties of the channel in particular deployment sites.
A crucial goal for ocean-sensing systems is to obtain spatially-rich data that allows us to understand the correlations between ocean processes. To achieve this, we consider a system consisting of swarms of underwater drifters that float freely with currents and therefore achieve high spatial sampling of the ocean. Our goal is to ensure that this system is self-organizing and autonomous which is key for practical large-scale deployments in remote regions. We consider a crucial aspect of data collection, namely, determining the locations at which data was sensed. Given our overall design goal, we propose a localization strategy where nodes collaborate to determine their positions autonomously without using long range transponders on surface buoys or ships. This in turn significantly impacts the cost and ease of deployment of such systems. Further, we determine optimum configurations for the swarm so that their position estimation error is minimized.
Since underwater acoustic (UWA) networks have the nature of long propagation delay, low bit rates and error-prone acoustic communication, protocols designed for underwater acoustic networks are significantly different from that of terrestrial radio networks. Limited by these nature of UWA channels, conventional medium access control (MAC) protocols of radio packet network ether have low efficiency or are not able to apply to underwater acoustic networks. It is necessary to develop an efficient MAC protocol for underwater acoustic networks. In this paper, a collision-free MAC protocol for UWA networks called Ordered Carrier Sense Multiple Access (Ordered CSMA) is proposed and analyzed. Ordered CSMA combines the concepts of round-robin scheduling and CSMA. In Ordered CSMA, each station transmits data frame in a fixed order. More specifically, each station transmits immediately after the data frame transmission of last station in the order, instead of waiting for a period of maximum propagation delay. To achieve this, each station is constantly sensing the carrier and listens to all received frames. Due to the characteristics of collision free and high channel utilization, Ordered CSMA shows a great MAC efficiency improvement in our simulations, compared to previous works.
A medium access control (MAC) protocol permits the nodes to access the shared medium by providing contention resolution mechanism. The design of MAC protocol in ad hoc networks becomes a more challenging task due to the interruptible energy source or limited battery life of nodes. This brings energy efficiency as the preliminary goal of the MAC protocol. MAC protocol for underwater acoustic sensor networks (UWASN) has to face even more challenges; many of them are due to the harsh underwater channel. Recently, a number of MAC protocols have been proposed for UWASN and selection of a suitable protocol has a great impact on the system efficiency. In this paper, we first highlight the unique aspects of acoustic channel and the problems associated with the MAC layer in UWASN. Existing MAC solutions for UWASN and open research issues are investigated and the summary of the protocols is provided to see the performance against different parameters considered in UWASN applications for selection of protocol.
Underwater networks allow investigation of many areas of the world not easily accessed by humans, but offer inter- esting challenges to device and protocol designers due to the unique channel conditions present when using acous- tic communications. The high transmit power of acoustic transceivers makes the medium access protocol a primary focus point for reducing energy consumption in energy lim- ited underwater devices. Scheduled protocols use very little power by eliminating collisions, but cannot adapt to chang- ing traffic conditions in the same way as random protocols. We attempt to bridge these two ideas by dividing time into scheduled and unscheduled access periods in order to yield the benefits of each protocol. We show that this technique increases the bits delivered per energy unit in many cases of interest. Additionally, the hybrid technique provides low latency for a wider range of traffic rates than either of the two protocols when considered individually. We also inves- tigate some of the design tradeoffs to consider when using a hybrid protocol. Categories and Subject Descriptors: C.2.2 (Computer-
Routing protocols for underwater wireless sensor networks
- G Han
- J Jiang
- N Bao
- W Wan
- M Guizani
HydroCast: Pressure routing for underwater sensor networks
- Y Noh
- U Lee
- S Lee