No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Underwater Wireless Sensor Network's Performance Enhancement with Cooperative Routing and Sink Mobility
Abstract
Network efficiency and reliability in terms of high throughput, energy conservation, low bit error rate (BER) and reduced delay are pre-requisites for many applications in Underwater Wireless Sensor Networks (UWSNs). However, distinctive features of UWSNs like low available bandwidth, large propagation delay, highly dynamic network topology, and high error probability pose many challenges for devising efficient and reliable communication protocols. In this paper, we therefore propose a protocol that focuses on enhancing network reliability and efficiency using cooperative routing and sink mobility. Many cooperative communication protocols have been developed which investigate the physical and MAC layer aspects to improve link efficiency in harsh underwater environment, however, at network layer, it is still unexplored. Similarly, cooperative routing is not yet collaborated with sink mobility. In this paper, Cooperative routing is implemented at network layer along with sink mobility. Potential relay and destination nodes for cooperative routing are selected on the basis of their depth as well as residual energy information. Data from source node is forwarded towards the destination node via relay nodes in a cooperative manner. Sink mobility further improves the results by directly gathering data from nodes. Based on the comprehensive simulations imple-mented in MATLAB, we observe that our scheme improves the performance in terms of network lifetime, energy efficiency and throughput along with reducing delay and BER. I. RELATED WORK Taking advantage of the broadcast nature of wireless transmission, cooperative communication has been proposed as a powerful alternative to reduce fading and other link impairments, where transmitted signal can be overheard by many unintended sensor nodes [1], [2]. Some related work presented in this domain is presented here An innovative physical layer solution involving cooperative communication is given in [2], where outage probability and capacity expressions are derived for cooperative multicarrier UAC systems with AF and DF relaying. Further, they pro-pose a receiver design to mitigate the degrading Doppler effects. In [3], Cooperative UnderWater Acoustic Multiple Input Single Output (CUWA-MISO) using DF is proposed where each node of network uses nearest adjacent node as a virtual antenna in a cooperative manner. It improves the system performance with the help of spatial diversity. Luo et al. [4], explored cooperation at MAC layer and proposed a distributed MAC protocol, that is, Coordinated Transmission MAC (CT-MAC) for underwater MIMO based network uplink communication. The scheme also addresses long propagation delay and collision among control packets in UAC. Authors in [5] suggested that channel efficiency is improved by applying asynchronous cooperative transmission for three dimensional UWSNs. Two typical forwarding schemes: AF and DF are implemented, analyzed and compared. In COoperative Best Relay Assessment (COBRA) [6], a relay selection criterion for underwater cooperative acoustic networks is developed. COBRA minimizes the One-way Packet Transmission (OPT) time. The best relay selection algorithm is used here. In [7], authors consider cooperative scheme with a design aspect from the physical layer to the network layer, leading to the efficient operation and reduced transceiver's complexity. It enhances the reliability by providing diversity gains through intermediate relay nodes.
... In DF, received signal is first corrected and then transmitted. Diversity combining techniques are applied on the received copies of data at the destination node [3]. These techniques further improve the quality of received data. ...
... COBRA improves network performance in terms of throughput and delivery ratio at the cost of long propagation delays. In [3], cooperative routing along with sink mobility are implemented and analysed at the network layer. Nodes for cooperative routing are selected on basis of their depth and residual energy information. ...
... Threshold optimized data sensing is used in our scheme as used in [3]. As the network starts, nodes start the sensing process. ...
Underwater environment suffers from a number of impairments which effect reliability and integrity of data being transmitted. Cooperative transmission is well known for reliable data transfer. Hence, cooperative routing can be implemented in Underwater Wireless Sensor Networks (UWSNs) in order to reduce the impact of existing link impairments on transmitted data. Cooperative routing involves data transmission via partner node (relay/destination node) towards sink. Selection of partner node for cooperative routing is to be performed on basis of a certain criterion so that effective results can be achieved. In this paper, two different partner node selection criteria are implemented and compared. We consider source node's depth threshold (d th ), potential relay/destination nodes's depth, residual energy and Signal to Noise Ratio (SNR) of the link connecting source node with potential relay/destination node as selection parameters. One criterion considers depth and residual energy while the other also takes link's SNR into account along with depth and residual energy. SNR based criterion is proved to outperform the one involving only depth and residual energy information. Simulation results show that the SNR based criterion achieves better results with respect to stability period and Packet Acceptance Ratio (PAR) along with reduced delay and packet drop.
... Underwater Wireless Sensor Networks UWSNs have gained a lot of importance in research area. Underwater Wireless Sensor Networks have a wide range of applications such as oceanographic, offshore exploration, pollution monitoring, oil extraction, etc [1], [2]. As we know, Wireless Sensor Networks WSNs consists of sensor nodes and sink similarly, Underwater Wireless Sensor Networks UWSNs also composed of sensor nodes to sense and transmit data to offshore data centers. ...
... Umar et al. in [2], proposed a protocol Underwater Wireless Sensor Network's performance enhancement with coperative routing and sink mobility. In this paper authors used cooperative routing for the selection of relay nodes and the destination nodes. ...
In this paper, a routing protocol; Maximum Coverage in Square field region (MCS) for Underwater Wireless Sensor Networks (UWSNs) is introduced. The overall area of the network is divided into ten sub regions and two mobile sinks (MSs) are deployed. The data is transmitted to the MS directly and mobility pattern of MS is adjusted in such a way that it covers the whole area of the network. When MS and sensor nodes are in transmission range of each other then data is transmitted. Simulation results show that MCS outperforms MC and EBECRP in terms of packet acceptance ratio and throughput.
... In [29], [30], authors proposed a cooperative "Depth and Energy Aware Dominating Set (DEADS)" routing scheme. ...
... Performance of the proposed scheme is presented in this section where two well-known schemes: DBR [34] and DEADS [29], [30], are used to compare the results. Simulations are performed in rounds where a round is used as a unit [35]. ...
Underwater Wireless Sensor Networks (UWSNs) serve as a proficient source to monitor aquatic environment. However, data communications and information routing within these systems offer many challenges. To ensure sufficient network lifetime, energy efficiency in routing protocols serve as a major concern in UWSNs. This paper presents an energy competent cooperative routing scheme known as Region Based Courier-nodes Mobility with Incremental Cooperative (RBCMIC) routing. The proposed scheme uses broadcast nature of wireless nodes and performs an incremental cooperative routing. A rigorous evaluation and verification of the proposed scheme with current state-of-the-art yield improved energy efficiency, resulting in extended network lifetime. The results show that an overall improvement of 20% is witnessed in energy usage, whereas a notable 89% improvement is achieved in end-to-end delay in comparison to DEADS protocol.
... COBRA improves network performance in terms of throughput, delivery ratio and reduces large propagation delay. In [8], Cooperative routing along with sink mobility are implemented and analysed at the network layer. Nodes for cooperative routing are selected on the basis of their depth and residual energy information. ...
... Threshold optimized data sensing is used in our scheme as used in [8]. As the network starts, nodes start the sensing process. ...
Underwater Wireless Sensor Networks (UWSNs) have attracted much concentration to support various applications like pollution monitoring, tsunami warnings, offshore exploration, tactical surveillance, etc. Network's efficiency and reliability in terms of high throughput, energy conservation, low Bit Error Rate (BER) and reduced delay are pre-requisites for many applications. However, distinctive features of UWSNs like low available bandwidth, large propagation delay, highly dynamic network topology, and high error probability pose many challenges for devising efficient and reliable communication protocols. In this thesis, we therefore propose a protocol along with its mathematical model that focuses on enhancing network reliability and efficiency via cooperative routing and sink mobility. Cooperative transmission is well known for reliable data transfer. Many cooperative communication protocols have been developed which investigate the physical and MAC layer aspects to improve link efficiency in harsh underwater environment, however, at network layer, it is still unexplored. Similarly, cooperative routing is not yet collaborated with sink mobility. We present a dominating set based cooperative routing algorithm at network layer. In this algorithm, potential relay and destination nodes for cooperative routing are selected on the basis of their depth and residual energy information. Data from source node is forwarded towards the destination node via relay node in a cooperative manner. Mobile Sinks directly gather data from destination nodes. Two different partner node selection criteria are also implemented and compared in this work. Selection of partner node (relay/destination node) for cooperative routing is to be performed on the basis of a certain criterion so that effective results can be achieved. We consider source node's depth threshold, potential relay/destination nodes's residual energy and Signal to Noise Ratio of the link connecting source node with potential relay/destination node as selection parameters. Based on the comprehensive simulations implemented in MATLAB, we observe that our proposed work improves the performance in terms of network lifetime, energy efficiency, throughput and reduces BER as compared to the existing depth based routing protocols.
... The nodes sense the data on the basis of threshold, forward it to transmission range sink or send it cooperatively to relay nodes. The protocol achieve better energy consumption and lower end to end delay as compared with relative routing protocols [9]. ...
... Protocol based on Cooperative and sink mobility [9] Reduce delay and bit error ratio, cooperative routing. ...
... In this paper, we present a mathematical model for cooperative routing along with sink mobility in UWSNs. This work is an extension of the work in [8] in which cooperative routing along with sink mobility is investigated at network layer. The proposed mathematical model involves an algorithm to compute the Dominating Set (DS) of a given network modeled as a digraph. ...
Performance enhancement of Underwater Wireless Sensor Networks (UWSNs)
in terms of throughput maximization, energy conservation and Bit Error Rate (BER)
minimization is a potential research area. However, limited available bandwidth, high
propagation delay, highly dynamic network topology, and high error probability leads to
performance degradation in these networks. In this regard, many cooperative communication
protocols have been developed that either investigate the physical layer or the Medium
Access Control (MAC) layer, however, the network layer is still unexplored. More
specifically, cooperative routing has not yet been jointly considered with sink mobility.
Therefore, this paper aims to enhance the network reliability and efficiency via dominating
set based cooperative routing and sink mobility. The proposed work is validated via
simulations which show relatively improved performance of our proposed work in terms
the selected performance metrics.
... Equal Gain Combining (EGC) technique is the diversity combining technique which is used at the destination node to improve the quality of the data signal. [5] In this paper, we proposed a new protocol named as Improved Adaptive Cooperative Routing (IACR). IACR is introduced as a successor of an already existing protocol called Adaptive Cooperation in EEDBR (ACE). ...
... A scheme is presented to improve link quality in terms of efficiency by cooperative retransmissions. Some forwarding techniques are used to forward data [8].In a study [9],to avoid the effect of multi path fading two asynchronous forwarding schemes are presented, named as underwater amplify and forward (UAF) and underwater decode and forward (UDF).In [10], relay nodes selection process is catered propagation delay.In [11], the relay nodes are selected on the basis of depth and residual energy. Mobile sinks (MS) are deployed in the network. ...
In Underwater Wireless Sensor Networks (UWSNs), reliability is one of the major concerns for large number of applications. The underwater environment is very harsh and noisy. Fading is common and unavoidable, therefore achieving reliable data transfer requires innovative routing solutions. This paper presents a energy efficient cooperative routing with varying Depth threshold (Dth) called Depth and Energy Aware Cooperative Routing Protocol for UWSNs (DEAC). DEAC utilizes the broadcast nature of sensor nodes by performing cooperative routing. Optimised value of Dth is selected for a source node and varied according to the number of alive neighbors of that source node.Potential destination node is selected from outside of Dth and a potential relay node is selected from inside. Destination and relay are selected on the basis of depth, residual energy and link quality between sensor nodes. Source node forwards a data packet to destination node from two ways, directly from source node to destination node and via relay to destination node. At destination, two data packets received from source node and relay node are combined using Maximum Ratio Combining Technique (MRC). Simulation results show that DEAC achieves better performance over some existing depth based routing protocols in terms of throughput, packet Acceptance ratio, packet drop and energy consumption.
... In [4], authors correlate the cooperative routing and mobility of the sink. While in this scheme potential relay and destination node is selected on depth of the network and residual energy of the node. ...
Design of underwater wireless sensor networks (UWSNs) is difficult because of limited battery energy of sensor nodes. Low bandwidth and energy consumption are major problems that we face in UWSNs, due to dynamic behavior of water in underwater environment. In our scheme, circular field is divided into ten sub-regions and each region is divided into eight sectors. Two mobile sinks move to cover the maximum area of the network field. Mobile Sink1 (M s1) covered the first five regions of the network and remaining covered by Mobile Sink2 (M s2). Both mobile sinks move sector wise in clockwise direction. Due to the mobility of the sinks. We have verify the better performance through simulation results of Network lifetime, Stability and Instability period, Energy consumption and Throughput.
... however, this also leaves some limitations as to find new trust values, much computation process is required in all the nodes that can cause energy comsuption and reduction in battery life time. Umar et al. (2014) proposed cooperative routing protocol along with mobile sinks. This protocol focuses on the efficiency and reliability. ...
The balance energy consumption of nodes is a key factor to prolong network lifetime. A sensor node in Underwater Wireless Sensor Networks (UWSNs), has very limited power battery, therefore, utilizing the power battery in efficient manner is still a challenging task. To enhance network lifetime, we proposed an Energy-Efficient Regional base Cooperative Routing (EERBCR) protocol with sink mobility for UWSNs. In EERBCR, we divided the network field in 12 regions, three by four vertically and horizontally respectively. Total numbers of four mobile sinks are positioned, having equal distance to each other while 100 sensors nodes are deployed randomly. Each mobile sink travels on pre-defined straight path and covers 3 regions. All the sensor nodes are in sleeping mode, until the sink arrives to their region, upon the arrival of sink node to a region, it broadcasts a hello message. All the nodes in that region receive that message and activate themselves. When the sink is about to leave the region, it broadcasts another packet, informing the nodes about its departure so that the nodes go back into sleeping mode. The simulation results show the validity of EERBCR as it performed better than Depth-Based Routing (DBR), Energy Efficient Depth-Based Routing (EEDBR) and depth and energy-aware dominating set (DEADS) protocols.
... In order to obtain further improvements in outcomes, SNR is further added to the measurement method. In [13], cooperative routing is introduced and evaluated on the network layer along with sink mobility. Based on their depth and remaining energy information, collaborative routing nodes are chosen. ...
Underwater wireless sensor networks (UWSNs) is an developing area for research in the wireless sensor networks (WSN) area. The normal method is to adapt for underwater use presently accessible terrestrial architectures and well-proven architectures. Underwater Wireless Sensor Networks (UWSNs) have drawn a lot of concentration to help multiple applications such as tracking pollution, tsunami warnings, offshore exploration, tactical tracking, etc. For many applications, the efficiency and reliability of the network in terms of high performance, energy conservation, low bit error rate (BER) and reduced delay are prerequisites. However, UWSN's unique characteristics such as low bandwidth available, big delay in propagation, extremely vibrant network topology, and high probability of error pose many difficulties in the development of effective and reliable communication protocols. Therefore, in this proposed work, along with its mathematical model, we suggest a protocol that focuses on improving network reliability and effectiveness through cooperative routing and sink mobility. For reliable data transmission, cooperative transmission is well known. Based on their residual energy data and depth , prospective relay and target nodes for cooperative routing are chosen in this algorithm. Data from the source node is transferred in a cooperative way to the target node via the relay node. Mobile Sinks collect information straight from the nodes of the location. We consider as selection parameters the depth threshold of the source node, the residual energy of the destination nodes/ potential relay and the SNR of the relating source node to the potential relay / destination node. In this work, two distinct selection criteria for partner nodes are also introduced and contrasted. Partner node selection (relay / destination node) for cooperative routing should be carried out on the grounds of a certain criterion in order to achieve efficient outcomes. Based on the extensive simulations carried out in MATLAB, we note that our suggested method increases performance in terms of energy efficiency, network life and decreases BER relative to the existing depth-based routing protocols.
... In [21], authors proposed a technique expanded the proficiency and unwavering quality of the system by utilizing the sink portability and helpful routing. Numerous conventions are created to perform participation with a specific end goal to enhance connect productivity by examining physical and MAC layer perspectives. ...
One of the real issues in UWSN is congestion control. The need is to plan an optimized congestion control scheme which enhances the network life time and in addition limits the usage of energy in data transmission from source to destination. In this paper, we propose a routing protocol called Dist-Coop in UWSN. Dist-Coop is a distributed cooperation based routing scheme which uses mechanism for optimized congestion control in noisy links of underwater environment. It is compact, energy proficient and high throughput opportunistic routing scheme for UWSN. In this proposed protocol architecture, we present congestion control with cooperative transmission of data packets utilizing relay sensors. The final objective is to enhance the network life time and forward information utilizing cooperation procedure, limiting energy consumption amid transmission of information. At destination node, combining strategy utilized is based on Signal-to-Noise Ratio (SNRC). Simulation results of Dist-Coop scheme indicate better outcomes in terms of energy consumption, throughput and network lifetime in contrast with Co-UWSN and EH-UWSN routing protocols. Dist-Coop has expended substantially less energy and better throughput when contrasted with these protocols.
... In [21], authors proposed a technique expanded the proficiency and unwavering quality of the system by utilizing the sink portability and helpful routing. Numerous conventions are created to perform participation with a specific end goal to enhance connect productivity by examining physical and MAC layer perspectives. ...
... U WSNS have lately been suggested as a potent means of supporting aquatic applications ranging from environmental monitoring to intrusion detection [1][2][3]. It is used in environmental, industrial and military domains for applications that vary in monitoring, navigation, surveillance and tracking, etc. [4][5]. Submarine observation system (SOS) is one of the most important premises of marine exploration, development and utilization of submarine resource. ...
Underwater sensor networks (UWSNs) is facing a great challenge in designing a routing protocol with longer network lifetime and higher packet delivery rate(PDR) under the complex underwater environment. In this paper, we propose an energy-aware and void-avoidable routing protocol (EAVARP). EAVARP includes layering phase and data collection phase. During the layering phase, concentric shells are built around sink node, and sensor nodes are distributed on different shells. Sink node performs hierarchical tasks periodically to ensure the validity and real-time of the topology. It makes EAVARP apply to dynamic network environment. During the data collection phase, data packets are forwarded based on different concentric shells through opportunistic directional forwarding strategy (ODFS), even if there are voids. The ODFS takes into account the remaining energy and data transmission of nodes in the same shell, and avoids cyclic transmission, flooding, and voids. The verification and analysis of simulation results show that the effectiveness of our proposed EAVARP in terms of selecting performance matrics in comparison to existing routing protocols.
Recent advances in underwater networking exploit the large propagation delays to schedule transmissions which increase the performance of underwater acoustic sensor networks. The underwater channel is broadcast in nature so it supports broadcast and multicast transmissions. In this paper, we discuss novel scheduling strategies, based on TDMA (Time Division Multiple Access), for UASNs where packets may be bound for multiple destinations. The main contributions are to establish an upper bound on the throughput of multicast networks, in which each packet has the same number of intended destinations, by exploiting large propagation delays, and explore network topologies that can achieve this bound. As an example, we study the throughput of unicast and multicast ring networks, including the properties of optimal, valid, perfect and fair transmission schedules. Further, several algorithms to find fair and optimal schedules for unicast and multicast ring networks are presented. Finally, we perform extensive simulations for uniform ring networks, as well as more general ring networks, in both noiseless and noisy underwater channels. Simulation results verify that the proposed algorithms can effectively determine the optimal schedules for ring networks, which achieve the maximum possible throughput and asymptotically approach the upper bound on the throughput of multicasting UASNs.
In this paper, for the first time, virtual antennas are used in an underwater acoustic wireless sensor network and their effects on total system performance are studied. In multiple input single output (MISO) channels, spacial diversity is used to improve the system performance. In certain networks, especially in underwater networks, nodes are too small to have more than one antenna. Therefore, to achieve spacial diversity gain, cooperation between adjacent nodes can be a p roper alternate method. F or this purpose, each node of network tries to use its nearest adjacent node as a virtual antenna at some portions of time and with the aid of space time coding this new antenna profits from spacial diversity. It means that a co operative virtual MISO scenario must be devised to determine the transmission and cooperation method in the network. Thus, the most frequently used cooperation schemes " decode and forward, " and " amplify and forward, " are applied, simulated and studied in an arbitrary underwater acoustic wireless sensor network and compared with the noncooperation mode. In this paper the alamouti space time coding, and the maximum ratio combiner are used to transmit, and combine data, respectively. Simulations show that virtual antenna in underwater wireless sensor networks can improve system performance up to 12.08%
We propose forwarding-function (íµí°¹ íµí°¹) based routing protocol for underwater sensor networks (UWSNs): improved adaptive mobility of courier nodes in threshold-optimized depth-based-routing (iAMCTD). Unlike existing depth-based acoustic protocols, the proposed protocol exploits network density for time-critical applications. In order to tackle flooding, path loss, and propagation latency, we calculate optimal holding time (íµí°» íµí±) and use routing metrics: localization-free signal-to-noise ratio (LSNR), signal quality index (SQI), energy cost function (ECF), and depth-dependent function (DDF). Our proposal provides on-demand routing by formulating hard threshold (íµí°» th), soft threshold (íµí± th), and prime energy limit (íµí±
prime). Simulation results verify effectiveness and efficiency of the proposed iAMCTD.
In this paper, we propose a cooperative transmission scheme for underwater acoustic sensor networks to enhance the network performance. Relay nodes are exploited as virtual antennas to achieve diversity gains. Based on the distinct characteristics of the underwater channel such as high transmission loss, propagation delay, and ambient noises, the paper presents a distributed cooperative scheme including networking protocols and cooperative transmissions at the physical layer in order to enhance the reliability by providing diversity gains through intermediate relay nodes. Destinations and potential relays are selected from a set of neighbor nodes that utilize distance cost and local measurement of the channel conditions into calculation. The simulation and numerical results show that the proposed scheme outperforms the traditional direct transmission schemes in terms of average energy consumption, packet delivery ratio, and end-to-end delay.
Cooperative communication has been studied extensively as a promising technique for improving the performance of terrestrial wireless networks. However, in underwater cooperative acoustic networks, long propagation delays and complex acoustic channels make the conventional relay selection schemes designed for terrestrial wireless networks inefficient. In this paper, we develop a new best relay selection criterion, called COoperative Best Relay Assessment (COBRA), for underwater cooperative acoustic networks to minimize the one-way packet transmission time. The new criterion takes into account both the spectral efficiency and the underwater long propagation delay to improve the overall throughput performance of the network with energy constraint. A best relay selection algorithm is also proposed based on COBRA criterion. This algorithm only requires the channel statistical information instead of the instantaneous channel state. Our simulation results show a significant decrease on one-way packet transmission time with COBRA. The throughput and delivery ratio performance improvement further verifies the advantages of our proposed criterion over the conventional channel state based algorithms.
Recently, underwater wireless sensor networks (UWSNs) have attracted much research attention from both academia and industry, in order to explore the vast underwater environment. UWSNs have peculiar characteristics; that is, they have large propagation delay, high error rate, low bandwidth, and limited energy. Therefore, designing network/routing protocols for UWSNs is very challenging. Also, in UWSNs, improving the energy efficiency is one of the most important issues since the replacement of the batteries of underwater sensor nodes is very expensive due to the unpleasant underwater environment. In this paper, we therefore propose an energy efficient routing protocol, named (energy-efficient depth-based routing protocol) EEDBR for UWSNs. EEDBR utilizes the depth of sensor nodes for forwarding data packets. Furthermore, the residual energy of sensor nodes is also taken into account in order to improve the network lifetime. Based on the comprehensive simulation using NS2, we observe that EEDBR contributes to the performance improvements in terms of the network lifetime, energy consumption, and end-to-end delay. A previous version of this paper was accepted in AST-2011 conference.
Improving network lifetime is a fundamental challenge of wireless sensor networks. One possible solution consists in making use of mobile sinks. Whereas theoretical analysis shows that this approach does indeed benefit network lifetime, practical routing protocols that support sink mobility are still missing. In this paper, in line with our previous efforts, we investigate the approach that makes use of a mobile sink for balancing the traffic load and in turn improving network lifetime. We engineer a routing protocol, MobiRoute, that effectively supports sink mobility. Through intensive simulations in TOSSIM with a mobile sink and an implementation of MobiRoute, we prove the feasibility of the mobile sink approach by demonstrating the improved network lifetime in several deployment scenarios.
Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved.
Network lifetime is crucial to 3D Under Water Sensor Networks (UWSNs) because it decreases more seriously than in 2D scenarios as the radius of the monitored region grows. We utilize sink mobility to solve the problem intuitively because the sink deployed in a vehicle is controllable while sensors are hard to be retrieved and recharged. It is hard to extend the results in 2D scenarios, i.e., a circular motion, to 3D UWSNs directly because there are more factors influencing network lifetime. However there is little literature on utilizing and analyzing sink mobility in 3D UWSNs. To simplify 3D sink mobility, we convert any motion to a combination of circular motions through mapping. After discussing the characteristics of circular motions, we propose MOSS, an optimal MObile Sink Strategy, to maximize the network lifetime in 3D UWSNs. Simulation results show that MOSS outperforms other motion strategies and improves the network lifetime at least in the order of 800% when R ≥ 5r, where R is the network radius and r is the transmission range of sensors.
The performance of Underwater Sensor Networks (UWSNs) can be severely affected by the dynamics of underwater environment. A surface sink is usually deployed at a pre-specified location to maximize one or more performance metrics. However, when the network is dynamic, a redeployment of surface sink should be considered to reduce the effect of mobility on the network performance. Redeployment can be done periodically, at times based on a mobility prediction models, or adaptively based on performance degradation. Unnecessary redeployment can result from using the periodic or prediction based redeployment. In this paper we present an adaptive dynamic sink redeployment strategy that enforces redeployment only if a reduction in energy consumption is guaranteed. The redeployment decision is based on routing information collected at the surface sink throughout network operation. We use a location unaware routing protocol “adaptive power controlled routing protocol” as the underlying routing strategy. When the mobility of the network is not severe, nodes tend to use a fixed power level to communicate with neighboring nodes or surface sink. However, if more nodes are switching to use higher power levels for communication and the energy consumption is increased a sink redeployment procedure is started. Surface sink then triggers localization and finds the optimal new location of surface sink to minimize total energy consumption. Simulation results show that adaptive sink redeployment achieves a considerable reduction in energy consumption.
Due to high bandwidth-efficiency, Multiple-Input Multiple-Output (MIMO) has emerged as a promising technique to address the low bandwidth challenges in underwater acoustic networks. Although extensive research has been conducted at the physical layer for underwater MIMO communications, the corresponding medium access control (MAC) is still largely unexplored, which makes it difficult to apply the existing underwater MIMO technologies in real applications. In this paper, we propose a distributed MAC protocol, called Coordinated Transmission MAC (CT-MAC), for underwater MIMO based network uplink communications. In CT-MAC, an efficient coordination scheme among immediate neighbors is designed for channel competition, which can avoid flooding overhead in the network. This scheme could also effectively address the long propagation delay problem and the collisions among long control packets in underwater acoustic communications. Protocol performance in terms of throughput and energy efficiency is evaluated via simulations which show significant improvements over handshaking based and random access based MIMO MAC approaches.
Multi-hop communication in Underwater Acoustic Sensor Network (UASN) brings new challenges in reliable data transmission. Recent work shows that data collection from underwater sensor nodes using Autonomous Underwater Vehicle (AUV) minimizes multi-hop data transmission, improving energy efficiency in UASN. However, due to continuous movements, AUV has limited communication time to collect data from sensor nodes in UASN. We therefore propose a novel underwater routing protocol, namely AEERP (AUV aided Energy Efficient Routing Protocol). In AEERP, an AUV collects data from gateway nodes. Among all the nodes, selected nodes play the role of gateway node for communication with AUV. Gateway nodes are selected based on RSSI values of the hello packet received from AUV. In addition, after consuming energy up to a certain threshold by a gateway node, another high energy node is selected as a gateway node. This adaptive selection of gateway node balances energy consumption increasing network lifetime. Mathematical analysis and NS-2 simulation show that AEERP performs better than Travel Salesperson Problem (TSP) in terms of energy cost and data delivery ratio.
Underwater acoustic sensor network (UWSN) has many important future applications in environmental, natural resources development, and geological oceanography. The recent advancement in underwater acoustic networking technologies and autonomous underwater vehicle (AUV) technologies enables the new underwater networking paradigm of using the AUV as the mobile sink for data collection. In this paper, we propose a coordination scheme for data gathering in UWSN using AUV. The mobility of AUV makes communication between AUV and sensor nodes challenging and it is difficult to guarantee that sensor nodes will be able to come out of sleep mode for communication. With different energy consumption requirements and constraints, the operation of AUV includes sending beacon messages, channel detection, and data reception, whereas that for the underwater sensor nodes involves prolonged sleep mode with sporadic data transmission. Therefore, different cycle periods would be required for AUV and sensor nodes. A new scheme is proposed and the shortest wakeup time and optimal amount of sleeping time for sensor nodes are investigated. Moreover, we demonstrate the effectiveness of our scheme when time synchronization does not exist between AUV and sensor nodes. Furthermore, transmission power control by using received signal strength (RSS) is introduced in order to decrease energy consumption and increase communication reliability. Simulation results show that the proposed scheme with power control leads to relative low energy consumption during communication under the harsh underwater environment compared with that without power control.
Although the techniques of cooperative transmission have been developed for terrestrial sensor networks in recent years to improve the bit-error-rate (BER) performance, the unique characteristics of the underwater acoustic communication channel, such as large and variable propagation delay and the three-dimensional network topology, make it necessary to reconsider the implementation and analysis of cooperative transmission in underwater acoustic networks. In this study, two asynchronous forwarding schemes, namely underwater amplify-and-forward (UAF) and underwater decode-and-forward (UDF), are proposed. Although the fading model for underwater channel is complex and there is still no consensus in the research community on a model which is applicable for all underwater channels, the authors simulation results show that both UDF and UAF have better performance than direct transmission under different underwater channel configurations, and there is a breathing effect for BER performance improvement caused by underwater multi-path fading. Finally, some insights on choosing the proper parameters to improve performance of underwater cooperative transmission are provided.
Providing scalable and ecient routing services in underwater sensor net- works (UWSNs) is very challenging due to the unique characteristics of UWSNs. Firstly, UWSNs often employ acoustic channels for communications because radio signals do not work well in water. Compared with radio-frequency channels, acous- tic channels feature much lower bandwidths and several orders of magnitudes longer propagation delays. Secondly, UWSNs usually have very dynamic topology as sen- sors move passively with water currents. Some routing protocols have been proposed to address the challenging problem in UWSNs. However, most of them assume that the full-dimensional location information of all sensor nodes in a network is known in prior through a localization process, which is yet another challenging issue to be solved in UWSNs. In this paper, we propose a depth-based routing (DBR) protocol. DBR does not require full-dimensional location information of sensor nodes. Instead, it needs only local depth information, which can be easily obtained with an inex- pensive depth sensor that can be equipped in every underwater sensor node. A key advantage of our protocol is that it can handle network dynamics eciently with- out the assistance of a localization service. Moreover, our routing protocol can take advantage of a multiple-sink underwater sensor network architecture without intro- ducing extra cost. We conduct extensive simulations. The results show that DBR can achieve very high packet delivery ratios (at least 95%) for dense networks with only small communication cost.
Significant progress has been made in terrestrial sensor net- works to revolutionize sensing and data collection. To bring the concept of long-lived, dense sensor networks to the un- derwater environment, there is a compelling need to develop low-cost and low-power acoustic modems for short-range communications. This paper presents our work in design- ing and developing such a modem. We describe our design rationale followed by details of both hardware and software development. We have performed preliminary tests with transducers for in-air communications.
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.
Underwater sensor networks (USNs) could provide real time in-situ monitoring to supply high spatio-temporal resolution capability. However underwater environment represents many challenges for sensor networks. It has become an urgent problem to get high temporal precision sampling data from USNs and to prolong USNspsila lifetime at the same time. In this paper, we present an underwater application model for collecting detail data from USNs with multiple mobile actors to get high temporal resolution capability. Our proposed complete strategy works in two ways: local base station collects sensorspsila data with regular time resolution, and mobile actors collect data from virtual clusters with high temporal resolution. We present three algorithms to accomplish the network model: a) area partitioning and actors scattering algorithm, b) sub-region optimizing algorithm, and c) virtual cluster formation algorithm. The paper present simulations to evaluate our proposed algorithms. The results indicates that our strategy can achieve lower end-to-end delay which is one eighth of that by former methods, actors can collect high temporal resolution data through virtual clusters, local network alternates within two network states (local USN and virtual clusters) freely. At the same time, since the proposed approach does not reduce local USNspsila lifetime, it has great potential in underwater network applications.
Cooperative Communication over Underwater Acoustic Channels
- S Al-Dharrab
- S Ibrahim
S. Al-Dharrab, and S. Ibrahim, "Cooperative Communication over Underwater Acoustic Channels", Diss. University of Waterloo, 2013.
Ad Hoc and Sensor Networks, Wireless Networks, Next Generation Internet
- H Yan
Yan, H., et al. "DBR: depth-based routing for underwater sensor networks," NETWORKING 2008 Ad Hoc and Sensor Networks, Wireless
Networks, Next Generation Internet. Springer Berlin Heidelberg, pp. 72-86, 2008.
IAMCTD: Improved Adaptive Mobility of Courier nodes in Threshold-optimized DBR Protocol for Underwater Wireless Sensor Networks
- M R Jafri
Jafri, M. R., et al. "IAMCTD: Improved Adaptive Mobility of Courier
nodes in Threshold-optimized DBR Protocol for Underwater Wireless
Sensor Networks," Broadband and Wireless Computing, Communication
and Applications (BWCCA), Eighth International Conference on. IEEE,
2013.