A reliable and energy‐efficient routing protocol for underwater wireless sensor networks

Recently, underwater wireless sensor networks (UWSNs) have attracted much research attention to support various applications for pollution monitoring, tsunami warnings, offshore exploration, tactical surveillance, etc. However, because of the peculiar characteristics of UWSNs, designing communication protocols for UWSNs is a challenging task. Particularly, designing a routing protocol is of the most importance for successful data transmissions between sensors and the sink. In this paper, we propose a reliable and energy‐efficient routing protocol, named R‐ERP²R (Reliable Energy‐efficient Routing Protocol based on physical distance and residual energy). The main idea behind R‐ERP²R is to utilize physical distance as a routing metric and to balance energy consumption among sensors. Furthermore, during the selection of forwarding nodes, link quality towards the forwarding nodes is also considered to provide reliability and the residual energy of the forwarding nodes to prolong network lifetime. Using the NS‐2 simulator, R‐ERP²R is compared against a well‐known routing protocol (i.e. depth‐based routing) in terms of network lifetime, energy consumption, end‐to‐end delay and delivery ratio. The simulation results proved that R‐ERP²R performs better in UWSNs.Copyright © 2012 John Wiley & Sons, Ltd.     

A Vector-Based Routing Protocol in Underwater Wireless Sensor Networks

One major concern shared by many researchers about underwater wireless sensor networks (UWSNs), with respect to the limitations and particularities of underwater environment, is the problem of routing. These limitations include three-dimensional topology, limited bandwidth, node movement, long delay, limited energy, and construction costs. The new routing protocols for underwater networks have been developed on the basis of voracious routing systems. The main problem with UWSNs is finding an efficient route between the source and the target to send more packets to the target with lower levels of energy consumption. In this research, by improving VBF algorithm, which is dependent on the radius of the routing pipe, an algorithm is introduced which considers pipe radius as a function of the environment’s dimensions and of the range and the number of nodes. Consequently, by changing one of these parameters, the radius of the routing pipe changes. However, to control the energy consumed by the nodes, there exists a function that, if the recipient node’s energy to receive the packet is much lower than that of the sender node, the proposed method reduces the size of the routing pipe’s radius to lessen its chance of being selected as the guiding node so that other nodes are able to have the chance of getting the packet’s guiding node. The proposed algorithm has been compared with VBVA, HHVBF, and VBF protocols; the simulation results obtained from NS-2 simulator indicate that the proposed protocol could cut back on energy consumption, especially in networks with high number of nodes, by relying on changing the width of the routing pipe in proportion to network density. It was also successful in delivering more packets in non-dense networks.     

Improved multicast routing in MANETs using link stability and route stability

The growing popularity of multimedia applications and services needs to support several quality of service metrics such as high throughput, low energy, and jitter, which is a challenging task in mobile ad hoc networks. Because of limited bandwidth, energy constraints, dynamic topology, transmission errors, and fluctuating link stability, the links between adjacent nodes are often not reliable and may break because of node mobility. Link breakage initiates the process of rerouting either at the sender node (the node at which the link breaks) or at the source node. In either case, it leads to packet loss, delivery delays, and increased control overheads. Hence, to attain a minimum quality of service, routing protocols must address the dynamic network topology. Uncertain and varying movement of nodes necessitates stability of the links between such nodes. The objective of this paper is to propose 2 protocols, the first based on link stability and the other based on route stability. Link stability identifies a stable link from the available links to the next hop and determines a stable end‐to‐end route. The probability of successful transmission of periodic packets is used as a link stability metric to assess the stable path. Acknowledgment ‐free packets are used to check connectivity in the network. Increased probability of successful transmission implies that the selected link is sustained for longer duration and can deliver packets more reliably or, as a consequence, results in a stable link to deliver a better data rate. With a stable link, there is a reduced possibility of retransmissions, reduced end‐to‐end delay, reduced control overheads, and enhanced data delivery ratio. Selection of the most stable route for data transmission improves the performance. Experimental results from simulations performed on EXata/Cyber v2.0 simulator reveal that our proposed protocols are an improvement over the existing protocols in terms of packet delivery ratio, average end‐to‐end delay, and average route lifetime, even without route optimization with the minor increase in control packets. A case study of the application of proposed protocols is also presented.     

Simulation‐based real‐time routing protocol with load distribution in wireless sensor networks

In wireless sensor networks (WSNs), sensors gather information about the physical world and the base station makes decision and then performs appropriate actions upon the environment. This technology enables a user to effectively sense and monitor from a distance in real‐time. WSNs demand real‐time forwarding which means messages in the network are delivered according to their end‐to‐end deadlines (packet lifetime). This paper proposes a novel real‐time routing protocol with load distribution (RTLD) that ensures high packet throughput with minimized packet overhead and prolongs the lifetime of WSN. The routing depends on optimal forwarding (OF) decision that takes into account of the link quality (LQ), packet delay time and the remaining power of next hop sensor nodes. The proposed mechanism has been successfully studied through simulation work. Copyright © 2009 John Wiley & Sons, Ltd.     

Energy‐efficient void avoidance geographic routing protocol for underwater sensor networks

Underwater wireless sensor networks (UWSNs) consist of a group of sensors that send the information to the sonobuoys at the surface level. Void area, however, is one of the challenges faced by UWSNs. When a sensor falls in a void area of communication, it causes problems such as high latency, power consumption, or packet loss. In this paper, an energy‐efficient void avoidance geographic routing protocol (EVAGR) has been proposed to handle the void area with low amount of energy consumption. In this protocol, a suitable set of forwarding nodes is selected using a weight function, and the data packets are forwarded to the nodes inside the set. The weight function includes the consumed energy and the depth of the candidate neighboring nodes, and candidate neighboring node selection is based on the packet advancement of the neighboring nodes toward the sonobuoys. Extensive simulation experiments were performed to evaluate the efficiency of the proposed protocol. Simulation results revealed that the proposed protocol can effectively achieve better performance in terms of energy consumption, packet drop, and routing overhead compared with the similar routing protocol.     

BRA: A Bidirectional Routing Abstraction for Asymmetric Mobile Ad Hoc Networks

Wireless links are often asymmetric due to heterogeneity in the transmission power of devices, non-uniform environmental noise, and other signal propagation phenomena. Unfortunately, routing protocols for mobile ad hoc networks typically work well only in bidirectional networks. This paper first presents a simulation study quantifying the impact of asymmetric links on network connectivity and routing performance. It then presents a framework called BRA that provides a bidirectional abstraction of the asymmetric network to routing protocols. BRA works by maintaining multi-hop reverse routes for unidirectional links and provides three new abilities: improved connectivity by taking advantage of the unidirectional links, reverse route forwarding of control packets to enable off-the-shelf routing protocols, and detection packet loss on unidirectional links. Extensive simulations of AODV layered on BRA show that packet delivery increases substantially (two-fold in some instances) in asymmetric networks compared to regular AODV, which only routes on bidirectional links.     

A gradient‐based multiple‐path routing protocol for low duty‐cycled wireless sensor networks

Routing in a low duty‐cycled wireless sensor network (WSN) has attracted much attention recently because of the challenge that low duty‐cycled sleep scheduling brings to the design of efficient distributed routing protocols for such networks. In a low duty‐cycled WSN, a big problem is how to design an efficient distributed routing protocol, which uses only local network state information while achieving low end‐to‐end (E2E) packet delivery delay and also high packet delivery efficiency. In this paper, we study low duty‐cycled WSNs wherein sensor nodes adopt pseudorandom sleep scheduling for energy saving. The objective of this paper is to design an efficient distributed routing protocol with low overhead. For this purpose, we design a simple but efficient hop‐by‐hop routing protocol, which integrates the ideas of multipath routing and gradient‐based routing for improved routing performance. We conduct extensive simulations, and the results demonstrate the high performance of the proposed protocol in terms of E2E packet delivery latency and packet delivery efficiency as compared with existing protocols. Copyright © 2014 John Wiley & Sons, Ltd.     

Enhanced tree routing for wireless sensor networks

Tree routing (TR) is a low-overhead routing protocol designated for simple, low-cost and low-power wireless sensor networks. It avoids flooding the network with path search and update messages in order to conserve bandwidth and energy by using only parent–child links for packet forwarding. The major drawback of TR is the increased hop-counts as compared with more sophisticated path search protocols. We propose an enhanced tree routing (ETR) strategy for sensor networks which have structured node address assignment schemes. In addition to the parent–child links, ETR also uses links to other one-hop neighbours if it is decided that this will lead to a shorter path. It is shown that such a decision can be made with minimum storage and computing cost by utilizing the address structure. Detailed algorithms for applying ETR to ZigBee networks are also presented. Simulation results reveal that ETR not only outperforms TR in terms of hop-counts, but also is more energy-efficient than TR.     

Probabilistic routing protocol for a hybrid wireless underground sensor networks

A wireless underground sensor network (WUSN) is defined as a network of wireless sensor devices in which all sensor devices are deployed completely underground (network sinks or any devices specifically for relay between sensors and a sink may be aboveground). In hybrid wireless underground sensor network (HWUSN), communication between nodes is implemented from underground‐to‐air or air‐to‐underground, not underground‐to‐underground. This paper proposes a novel hybrid underground probabilistic routing protocol that provides an efficient means of communication for sensor nodes in HWUSN. In addition, signal propagation based on the shadowing model for underground medium is developed. The proposed routing protocol ensures high packet throughput, prolongs the lifetime of HWUSN and the random selection of the next hop with multi‐path forwarding contributes to built‐in security. Moreover, the proposed mechanism utilizes an optimal forwarding (OF) decision that takes into account of the link quality, and the remaining power of next hop sensor nodes. The performance of proposed routing protocol has been successfully studied and verified through the simulation and real test bed. Copyright © 2011 John Wiley & Sons, Ltd.     

Energy‐aware geographic routing in wireless sensor networks with anchor nodes

Energy efficiency has become an important design consideration in geographic routing protocols for wireless sensor networks because the sensor nodes are energy constrained and battery recharging is usually not feasible. However, numerous existing energy‐aware geographic routing protocols are energy‐inefficient when the detouring mode is involved in the routing. Furthermore, most of them rarely or at most implicitly take into account the energy efficiency in the advance. In this paper, we present a novel energy‐aware geographic routing (EAGR) protocol that attempts to minimize the energy consumption for end‐to‐end data delivery. EAGR adaptively uses an existing geographic routing protocol to find an anchor list based on the projection distance of nodes for guiding packet forwarding. Each node holding the message utilizes geographic information, the characteristics of energy consumption, and the metric of advanced energy cost to make forwarding decisions, and dynamically adjusts its transmission power to just reach the selected node. Simulation results demonstrate that our scheme exhibits higher energy efficiency, smaller end‐to‐end delay, and better packet delivery ratio compared to other geographic routing protocols. Copyright © 2011 John Wiley & Sons, Ltd.     

Probabilistic Forwarding Decision Scheme for Reliable Geocasting in Wireless Sensor Networks

Geocasting is an important communication service in wireless sensor networks. Most of the existing geocasting protocols assume that sensor nodes and the area of interest have accurate location information. However, this assumption is unreasonable if localization systems or schemes cannot work well. This study proposes an efficient probabilistic forwarding decision scheme for reliable geocasting in virtual coordinate-based wireless sensor networks. The proposed scheme uses directional code and hop distance to identify sensor node’s location. The sensor node determines a direction-based probability and a distance-based probability derived from its directional code and hop distance, respectively. The sensor node depends on the two probabilities to determine its ultimate forwarding probability. Simulation results confirm that the proposed scheme outperforms the pure direction-based forwarding scheme in packet delivery ratio though it occurs more packets. Results also show that the direction-based probability significantly dominates the geocasting performance.     

RQAR: Location-free reliable and QoS-aware routing protocol for mobile sink underwater wireless sensor networks

Underwater Wireless Sensor Networks (UWSNs) have attracted attention from academics and industries due to many applications such as pollution monitoring, military, tsunami warning, and underwater exploration. One of the effective factors in these applications is efficient communication between underwater sensors. But this process is very challenging in UWSNs due to special conditions and underwater harsh environments. Therefore, designing routing protocols for efficient communication between sensors and sink is an important issue in UWSNs. In this context, this paper proposed a location-free Reliable and QoS-Aware Routing (RQAR) protocol for mobile sink UWSNs. RQAR designed using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and does not require the position information of the sensor nodes, which is cumbersome and difficult to obtain. Proposed protocol considers multiple parameters including link quality, hop count, congestion, and residual energy for qos support, and reliable data delivery RQAR also minimizes the effects of hole occurrence by increasing the transmission range as much as possible and ensures communication stability. The simulation results using NS2 showed the superiority of RQAR in improving end-to-end delay, packet delivery ratio, and network throughput compared to the previous methods.     

LSAPSP: Load distribution‐based slot allocation and path establishment using optimized substance particle selection in sensor networks

Sensor node energy conservation is the primary design parameters in wireless sensor networks (WSNs). Energy efficiency in sensor networks directly prolongs the network lifetime. In the process of route discovery, each node cooperates to forward the data to the base station using multi‐hop routing. But, the nodes nearer to the base station are loaded more than the other nodes that lead to network portioning, packet loss and delay as a result nodes may completely loss its energy during the routing process. To rectify these issues, path establishment considers optimized substance particle selection, load distribution, and an efficient slot allocation scheme for data transmission between the sensor nodes in this paper. The selection of forwarders and conscious multi‐hop path is selected based on the route cost value that is derived directly by taking energy, node degree and distance as crucial metrics. Load distribution based slot allocation method ensures the balance of data traffic and residual energy of the node in areal‐time environment. The proposed LSAPSP simulation results show that our algorithm not only can balance the real‐time environment load and increase the network lifetime but also meet the needs of packet loss and delay.     

EARQ: Energy Aware Routing for Real-Time and Reliable Communication in Wireless Industrial Sensor Networks

Wireless industrial sensor networks are wireless sensor networks which have been adapted to industrial applications. Most techniques for wireless sensor networks can be applied to wireless industrial sensor networks. However, for industrial applications of wireless industrial sensor networks, new requirements such as real-time, reliable delivery need to be considered. In this paper, we propose EARQ, which is a novel routing protocol for wireless industrial sensor networks. It provides real-time, reliable delivery of a packet, while considering energy awareness. In EARQ, a node estimates the energy cost, delay and reliability of a path to the sink node, based only on information from neighboring nodes. Then, it calculates the probability of selecting a path, using the estimates. When packet forwarding is required, it randomly selects the next node. A path with lower energy cost is likely to be selected, because the probability is inversely proportional to the energy cost to the sink node. To achieve real-time delivery, only paths that may deliver a packet in time are selected. To achieve reliability, it may send a redundant packet via an alternate path, but only if it is a source of a packet. Experimental results show that EARQ is suitable for industrial applications, due to its capability for energy efficient, real-time, reliable communications.      

G-STAR: Geometric STAteless Routing for 3-D wireless sensor networks

3-D aerial and underwater sensor networks have found various applications in natural habitat monitoring, weather/earthquake forecast, terrorist intrusion detection, and homeland security. The resource-constrained and dynamic nature of such networks has made the stateless routing protocol with only local information a preferable choice. However, most of the existing routing protocols require sensor nodes to either proactively maintain the state information or flood the network from time to time. The existing stateless geometric routing protocols either fail to work in 3-D environments or have tendency to produce lengthy paths. In this paper, we propose a novel routing protocol, namely Geometric STAteless Routing (G-STAR) for 3-D networks. The main idea of G-STAR is to distributively build a location-based tree and find a path dynamically. G-STAR not only generalizes the notion of geographic routing from two modes to one mode, but also guarantees packet delivery even when the location information of some nodes is either inaccurate or simply unavailable regardless of the uses of virtual coordinates. In addition, we develop a light-weight path pruning algorithm, namely Branch Pruning (BP), that can be combined with G-STAR to enhance the routing performance with very little overhead. The extensive simulation results by ns-2 have shown that the proposed routing protocols perform significantly better than the existing 3-D geometric routing protocols in terms of delivery rate with competitive hop stretch. We conclude that the proposed protocols serve as a strong candidate for future high-dimensional sensor networks.     

一种能量平衡的无线体域网络AODV多播路由发现协议

在动态网络拓扑中,AODV协议通过数据源节点S泛洪广播RREQ消息请求到任意目标节点D的路由,而在无线体域网络中,只有一个sink目标节点,除最短跳数路由上的节点外,其他参与RREQ接收和转发的节点浪费了能量。提出了一种能量平衡的无线体域网络AODV多播路由发现协议,通过在节点广播的hello消息中增加到sink的最小跳数hops、到sink的下一跳节点next和节点本身是否具备转发能力isforward 3 个参数,只选择能到达sink节点的邻居节点参与转发RREQ消息,变广播为多播,有效地降低了路由发现的能量开销,并通过能量平衡延长了WBAN的使用寿命。性能分析与模拟实验表明,该协议在RREQ数量、数据传输率和能量消耗等方面优于相似协议EAAODV。     

MRP: A Localization-Free Multi-Layered Routing Protocol for Underwater Wireless Sensor Networks

Underwater Wireless Sensor Networks (UWSNs) have distinctive characteristics due to the use of acoustic signals as its physical medium for communications, including high propagation delay, limited bandwidth and high error rates. Hence, designing communication protocols, particularly, an efficient routing protocol for UWSNs is a challenging issue. Routing protocols can take advantage of the localization of sensor nodes. However, the localization itself is not impeccable in UWSNs. In this paper, we therefore propose a localization-free routing protocol named MRP (multi-layered routing protocol) for UWSNs. MRP utilizes super nodes in order to eliminate the need of localization. MRP works in two phases: Layering phase and Data forwarding phase. During layering phase, different layers are formed around the super nodes. In data forwarding phase, data packets are forwarded based on these layers. Through simulation study using NS-2 simulator, we proved that MRP contributes significant performance improvements against representative routing protocols.     

An evaluation of routing in vehicular networks using analytic hierarchy process

This paper presents a comprehensive study of the performance of routing protocols in distributed vehicular networks. We propose a novel and efficient routing protocol, namely cross‐layer, weighted, position‐based routing, which considers link quality, mobility and utilisation of nodes in a cross layer manner to make effective position‐based forwarding decisions. An analytic hierarchy process approach is utilised to combine multiple decision criteria into a single weighting function and to perform a comparative evaluation of the effects of aforementioned criteria on forwarding decisions. Comprehensive simulations are performed in realistic representative urban scenarios with synthetic and real traffic. Insights on the effect of different communication and mobility parameters are obtained. The results demonstrate that the proposed protocol outperforms existing routing protocols for vehicular ad hoc networks, including European Telecommunications Standards Institute (ETSI's) proposed greedy routing protocol, greedy traffic aware routing protocol and advanced greedy forwarding in terms of combined packet delivery ratio, end‐to‐end delay and overhead. Copyright © 2015 John Wiley & Sons, Ltd.     

Reliable routing mechanism based on neighbor stability for MANET

One critical issue for routing in mobile Ad-hoc networks (MANETs) is how to select a reliable path that can last longer because mobility may cause frequent breakdown in radio links. A novel routing mechanism based on link lifetime estimation is proposed in this article. In this mechanism, the node's received signal strength is obtained continuously by using Newton interpolation polynomial, and by method of middle value and interception, the reference points are selected to estimate the link lifetime. With the constraint of link lifetime and hop counts, the source nodes set up the route hop by hop. The simulations show that link lifetime can be predicted regardless of mobility pattern. Moreover, the route discovery times and packet drop ratio can be reduced by the proposed mechanism, and thus improving the performance of MANETs.     

LRP: Link quality‐aware queue‐based spectral clustering routing protocol for underwater acoustic sensor networks

Recently, underwater acoustic sensor networks (UASNs) have been considered as a promising approach for monitoring and exploring the oceans in lieu of traditional underwater wireline instruments. As a result, a broad range of applications exists ranging from oil industry to aquaculture and includes oceanographic data collection, disaster prevention, offshore exploration, assisted navigation, tactical surveillance, and pollution monitoring. However, the unique characteristics of underwater acoustic communication channels, such as high bit error rate, limited bandwidth, and variable delay, lead to a large number of packet drops, low throughput, and significant waste of energy because of packets retransmission in these applications. Hence, designing an efficient and reliable data communication protocol between sensor nodes and the sink is crucial for successful data transmission in underwater applications. Accordingly, this paper is intended to introduce a novel nature‐inspired evolutionary link quality‐aware queue‐based spectral clustering routing protocol for UASN‐based underwater applications. Because of its distributed nature, link quality‐aware queue‐based spectral clustering routing protocol successfully distributes network data traffic load evenly in harsh underwater environments and avoids hotspot problems that occur near the sink. In addition, because of its double check mechanism for signal to noise ratio and Euclidean distance, it adopts opportunistically and provides reliable dynamic cluster‐based routing architecture in the entire network. To sum up, the proposed approach successfully finds the best forwarding relay node for data transmission and avoids path loops and packet losses in both sparse and densely deployed UASNs. Our experimental results obtained in a set of extensive simulation studies verify that the proposed protocol performs better than the existing routing protocols in terms of data delivery ratio, overall network throughput, end‐to‐end delay, and energy efficiency.