Showing papers in "Wireless Networks in 2018"

A reliable energy-efficient pressure-based routing protocol for underwater wireless sensor network

Abstract: Recently, Underwater Wireless Sensor Networks (UWSNs) has witnessed significant attention from both academia and industries in research and development, due to the growing number of applications for wide range of purposes including commercial, scientific, environmental and military. Some of the major applications include pollution monitoring, tactical surveillance, tsunami warnings and offshore exploration. Efficient communication among sensors in UWSNs is a challenging task due to the harsh environments and peculiar characteristics of UWSNs. Therefore, design of routing protocol for efficient communication among sensors and sink is one of the fundamental research themes in UWSNs. In this context, this paper proposes a location-free Reliable and Energy efficient Pressure-Based Routing (RE-PBR) protocol for UWSNs. RE-PBR considers three parameters including link quality, depth and residual energy for balancing energy consumption and reliable data delivery. Specifically, link quality is estimated using triangle metric method. A light weight information acquisition algorithm is developed for efficient knowledge discovery of the network. Multi-metric data forwarding algorithm is designed based on route cost calculation which utilizes residual energy and link quality. Simulations are carried out in NS-2 with Aqua-Sim package to evaluate the performance of RE-PBR. The performance of the proposed protocol is compared with the stat-of-the-art techniques: DBR and EEDBR. The comprehensive performance evaluation attests the benefit of RE-PBR as compared to the state-of-the-art techniques in terms of network lifetime, energy consumption, end-to-end delay and packet delivery ratio.

A novel support vector machine based intrusion detection system for mobile ad hoc networks

Abstract: The performance of mobile ad hoc networks (MANETs) is significantly affected by the malicious nodes. One of the most common attacks in MANETs is denial of service (DoS); a type of intrusion specifically designed to target service integrity and availability of a certain network node. Hence, it is important to use an efficient intrusion detection system (IDS) that detects and removes the malicious nodes in the network to improve the performance by monitoring the network traffic continuously. The main contribution of this paper is the integration of an IDS into MANETs as a reliable and potent solution. A new approach to intrusion detection is developed based on support vector machine algorithm. The proposed IDS can detect the DoS type attacks at a high detection rate with a simple structure and short computing time. It is shown by extensive computer simulation that the proposed IDS improves the reliability of the network significantly by detecting and removing the malicious nodes in the system. The performance of the suggested approach is independent of the network routing protocol. The detection rate of the system is also not effected by node mobility and network size.

Intelligent energy-aware efficient routing for MANET

Abstract: Designing an energy efficient routing protocol is one of the main issue of Mobile Ad-hoc Networks (MANETs) It is challenging task to provide energy efficient routes because MANET is dynamic and mobile nodes are fitted with limited capacity of batteries The high mobility of nodes results in quick changes in the routes, thus requiring some mechanism for determining efficient routes In this paper, an Intelligent Energy-aware Efficient Routing protocol for MANET (IE2R) is proposed In IE2R, Multi Criteria Decision Making (MCDM) technique is used based on entropy and Preference Ranking Organization METHod for Enrichment of Evaluations-II (PROMETHEE-II) method to determine efficient route MCDM technique combines with an intelligent method, namely, Intuitionistic Fuzzy Soft Set (IFSS) which reduces uncertainty related to the mobile node and offers energy efficient route The proposed protocol is simulated using the NS-2 simulator The performance of the proposed protocol is compared with the existing routing protocols, and the results obtained outperforms existing protocols in terms of several network metrics

Improving lifetime and network connections of 3D wireless sensor networks based on fuzzy clustering and particle swarm optimization

Abstract: 3D wireless sensor network (3D-WSN) has attracted significant interests in recent years due to its applications in various disciplinary fields such as target detection, object tracking, and security surveillance. An important problem in 3D WSN is the sensor energy optimization which determines a topology of sensors to prolong the network lifetime and energy expenditure. The existing methods for dealing with this matter namely low energy adaptive clustering hierarchy, LEACH-centralized, K-Means, single hop clustering and energy efficient protocol, hybrid-LEACH and fuzzy C-means organize the networks into clusters where non-cluster head nodes mainly carry out sensing tasks and send the information to the cluster head, while cluster head collect data from other nodes and send to the base station (BS). Although these algorithms reduce the total energy consumption of the network, they also create a large number of network disconnect which refers to the number of sensors that cannot connect to its cluster head and the number of cluster heads that cannot connect to the BS. In this paper, we propose a method based on fuzzy clustering and particle swarm optimization to handle this problem. Experimental validation on real 3D datasets indicates that the proposed method is better than the existing methods.

Trust based authentication technique for cluster based vehicular ad hoc networks (VANET)

Abstract: Since Vehicular ad hoc networks (VANETs) are vulnerable to various kinds of attacks, there is a need to fulfill the security requirements like message privacy, integrity, and authentication. The authentication technique is said to be efficient if it detects compromised nodes accurately with less complexity, reduced authentication delay, and keying overhead. In this paper, a trust-based authentication scheme for cluster-based VANETs is proposed. The vehicles are clustered, and the trust degree of each node is estimated. The trust degree is a combination of direct trust degree and indirect trust degree. Based on this estimated trust degree, cluster heads are selected. Then, each vehicle is monitored by a set of verifiers, and the messages are digitally signed by the sender and encrypted using a public/ private key as distributed by a trusted authority and decrypted by the destination. This verifies the identity of sender as well as receiver thus providing authentication to the scheme. By simulation results, we prove that the proposed technique provides high security with less overhead and delay.

An efficient dynamic traffic light scheduling algorithm considering emergency vehicles for intelligent transportation systems

Abstract: Traffic lights have been installed throughout road networks to control competing traffic flows at road intersections. These traffic lights are primarily intended to enhance vehicle safety while crossing road intersections, by scheduling conflicting traffic flows. However, traffic lights decrease vehicles' efficiency over road networks. This reduction occurs because vehicles must wait for the green phase of the traffic light to pass through the intersection. The reduction in traffic efficiency becomes more severe in the presence of emergency vehicles. Emergency vehicles always take priority over all other vehicles when proceeding through any signalized road intersection, even during the red phase of the traffic light. Inexperienced or careless drivers may cause an accident if they take inappropriate action during these scenarios. In this paper, we aim to design a dynamic and efficient traffic light scheduling algorithm that adjusts the best green phase time of each traffic flow, based on the real-time traffic distribution around the signalized road intersection. This proposed algorithm has also considered the presence of emergency vehicles, allowing them to pass through the signalized intersection as soon as possible. The phases of each traffic light are set to allow any emergency vehicle approaching the signalized intersection to pass smoothly. Furthermore, scenarios in which multiple emergency vehicles approach the signalized intersection have been investigated to select the most efficient and suitable schedule. Finally, an extensive set of experiments have been utilized to evaluate the performance of the proposed algorithm.

Trust evaluation method for clustered wireless sensor networks based on cloud model

Abstract: Trust Management has been proved to be an effective method to detect malicious nodes and ensure security in Wireless Sensor Networks (WSNs). While, most existing trust management methods are not good at dealing with uncertainty of trust relationship such as randomness, fuzziness in WSNs, which leads to inaccurate trust metric. In this paper, a trust evaluation method for clustered wireless sensor networks based on cloud model is proposed and evaluated, which implements the conversion between qualitative and quantitative of sensor nodes’ trust metrics in order to achieve better trust evaluation. Firstly, the method considers multi-factors including communication factor, message factor and energy factor and builds mathematical model for each trust factor to get factor trust cloud. Secondly, immediate trust cloud is calculated by assigning adjustive weights for each factor trust cloud and combining them. Thirdly, recommendation trust cloud and immediate trust cloud are synthesized according to time sensitive factor in order to get final trust cloud. Furthermore, the final trust cloud of sensor node is converted to trust grade by trust cloud decision-making. Verification Experiments manifest that the proposed method has feasibility and accuracy in the aspect of evaluating sensor nodes’ trust. Moreover, comparison experiments under different attacks show that our method is sensitive to multiple attacks, it outperforms other trust evaluation methods not only in the accuracy of detecting malicious nodes, but also in the tolerance of abnormal conditions.

A boolean spider monkey optimization based energy efficient clustering approach for WSNs

Abstract: Wireless sensor network (WSN) consists of densely distributed nodes that are deployed to observe and react to events within the sensor field. In WSNs, energy management and network lifetime optimization are major issues in the designing of cluster-based routing protocols. Clustering is an efficient data gathering technique that effectively reduces the energy consumption by organizing nodes into groups. However, in clustering protocols, cluster heads (CHs) bear additional load for coordinating various activities within the cluster. Improper selection of CHs causes increased energy consumption and also degrades the performance of WSN. Therefore, proper CH selection and their load balancing using efficient routing protocol is a critical aspect for long run operation of WSN. Clustering a network with proper load balancing is an NP-hard problem. To solve such problems having vast search area, optimization algorithm is the preeminent possible solution. Spider monkey optimization (SMO) is a relatively new nature inspired evolutionary algorithm based on the foraging behaviour of spider monkeys. It has proved its worth for benchmark functions optimization and antenna design problems. In this paper, SMO based threshold-sensitive energy-efficient clustering protocol is proposed to prolong network lifetime with an intend to extend the stability period of the network. Dual-hop communication between CHs and BS is utilized to achieve load balancing of distant CHs and energy minimization. The results demonstrate that the proposed protocol significantly outperforms existing protocols in terms of energy consumption, system lifetime and stability period.

SLAP: Succinct and Lightweight Authentication Protocol for low-cost RFID system

Abstract: Data security is crucial for a RFID system. Since the existing RFID mutual authentication protocols encounter the challenges such as security risks, poor performance, an ultra-lightweight authentication protocol named Succinct and Lightweight Authentication Protocol (SLAP) is proposed. SLAP is only composed of bitwise operations like XOR, left rotation and conversion which is easy to implement on a passive tag. The proposed conversion operation as the main security component guarantees the security of RFID system with the properties such as irreversibility, sensibility, full confusion and low complexity, which better performed or even absent in other previous protocols. Security analysis shows that SLAP guarantees the functionalities of mutual authentication as well as resistance to various attacks such as de-synchronization attack, replay attack and traceability attack, etc. Furthermore, performance evaluation also indicates that the proposed scheme outperforms the existing protocols in terms of less computation requirement and fewer communication messages during authentication process.

New path planning model for mobile anchor-assisted localization in wireless sensor networks

Abstract: As event detection is one of the main purposes of using wireless sensor networks (WSNs), the nodes location is essential to determine the location of that event when it occurs. Many localization models have been proposed in the literature. One of the solutions is to deploy a set of location-aware nodes, called anchors, to exchange information with the other nodes in order to help estimate their own location. Another promising proposal involves replacing these sets of anchors with only one mobile anchor. While this proposal seems to provide favorable results, it brings new challenges. The main challenge is to find an optimal path for the mobile anchor to follow while taking into account the need to provide highly accurate data and more localizable nodes in less time and with less energy. In this paper, we introduced a new static path planning model for mobile anchor-assisted localization in WSNs. Our proposed model guarantees that all nodes are able to receive the localization information, thus, estimate their own location with higher localization accuracy in comparison to similar static models. Moreover, this model overcomes the problem of collinearity and takes into account the metrics of precision and energy consumption as well as accuracy, localization ratio and the path length of the mobile anchor.

A survey on sensor placement for contamination detection in water distribution systems

Abstract: Frequent water pollution incidents have occurred recently, leading to severe damages, economic loss, and long-lasting society impact. Therefore, installation of water quality monitoring sensors in water distribution system (WDS) has been advocated as a viable solution to enable real-time pollution detection and thus the mitigation of the risks associated with catastrophic contamination incidents. Given the significant cost of placing sensors at all locations in a network, a critical issue is where to deploy the sensors within the distribution system while the network still gets covered. Although there exist a significant number of articles on sensor placement, WDS for contamination detection is unique comparing to other networks such as power grids, road networks, structural networks and microwave radio networks. In this paper, we conduct a comprehensive literature survey on the sensor placement problem for contamination detection in WDS, with a special focus on optimization strategies and framework. Current challenges, issues, and research directions are also identified and discussed.

Band notched UWB circular monopole antenna with inductance enhanced modified mushroom EBG structures

Abstract: Circular monopole antenna for ultra-wide band applications with notch band transition from WLAN to WiMAX is presented. The proposed antenna rejects WiMAX band (3.3---3.8?GHz). Antennas utilises modified mushroom-type electromagnetic band gap (EBG) structures to achieve band-notched designs. The proposed inductance enhanced modified EBG structures are 34?% compact than the conventional mushroom EBG structures. The band notched antenna designs using EBG structures have advantages like notch-frequency tuning, antenna design independent approach and omnidirectional radiation pattern. The step wise effect of inductance enhancement and tuning of notch from WLAN band (5---6?GHz) to WiMAX band is shown. Effect of variation of EBG structure parameters on which notched frequency depends is investigated. The proposed antenna has been fabricated on low cost FR4 substrate with overall dimensions as (42?נ50?נ1.6)?mm3. Measured results are in good agreement with simulated ones.

Data offloading and task allocation for cloudlet-assisted ad hoc mobile clouds

Abstract: Nowadays, although the data processing capabilities of the modern mobile devices are developed in a fast speed, the resources are still limited in terms of processing capacity and battery lifetime. Some applications, in particular the computationally intensive ones, such as multimedia and gaming, often require more computational resources than a mobile device can afford. One way to address such a problem is that the mobile device can offload those tasks to the centralized cloud with data centers, the nearby cloudlet or ad hoc mobile cloud. In this paper, we propose a data offloading and task allocation scheme for a cloudlet-assisted ad hoc mobile cloud in which the master device (MD) who has computational tasks can access resources from nearby slave devices (SDs) or the cloudlet, instead of the centralized cloud, to share the workload, in order to reduce the energy consumption and computational cost. A two-stage Stackelberg game is then formulated where the SDs determine the amount of data execution units that they are willing to provide, while the MD who has the data and tasks to offload sets the price strategies for different SDs accordingly. By using the backward induction method, the Stackelberg equilibrium is derived. Extensive simulations are conducted to demonstrate the effectiveness of the proposed scheme.

A novel approach for mitigating gray hole attack in MANET

Abstract: Mobile ad hoc network (MANET) is defined as the category of wireless network that is capable of operating without any fixed infrastructure. The main assumption considered in this network is that all nodes are trusted nodes but in real scenario, some nodes can be malicious node and therefore can perform selective dropping of data packets instead of forwarding the data packets to the destination node. These malicious nodes behave normally during route discovery phase and afterwards drop fractions of the data packets routed through them. Such type of attack is known as smart gray hole attack which is variation of sequence number based gray hole attack. In this paper, we have launched smart gray hole attack and proposed a new mechanism for mitigating the impact of smart gray hole attack. Mitigating Gray hole Attack Mechanism (MGAM) uses several special nodes called as G-IDS (gray hole-intrusion detection system) nodes which are deployed in MANETs for detecting and preventing smart gray hole attack. G-IDS nodes overhear the transmission of its neighbouring nodes and when it detects that the node is dropping the data packets which are greater than threshold value then it broadcast the ALERT message in the network notifying about the identity of malicious node. The identified malicious is then blocked from further its participation by dropping the request and reply packet. In order to validate the effectiveness of our proposed mechanism, NS-2.35 simulator is used. The simulation results show that the proposed mechanism performs slightly well as compared with the existing scheme under smart gray hole attack.

A framework of blockchain-based secure and privacy-preserving E-government system

Abstract: Electronic government (e-government) uses information and communication technologies to deliver public services to individuals and organisations effectively, efficiently and transparently. E-government is one of the most complex systems which needs to be distributed, secured and privacy-preserved, and the failure of these can be very costly both economically and socially. Most of the existing e-government systems such as websites and electronic identity management systems (eIDs) are centralized at duplicated servers and databases. A centralized management and validation system may suffer from a single point of failure and make the system a target to cyber attacks such as malware, denial of service attacks (DoS), and distributed denial of service attacks (DDoS). The blockchain technology enables the implementation of highly secure and privacy-preserving decentralized systems where transactions are not under the control of any third party organizations. Using the blockchain technology, exiting data and new data are stored in a sealed compartment of blocks (i.e., ledger) distributed across the network in a verifiable and immutable way. Information security and privacy are enhanced by the blockchain technology in which data are encrypted and distributed across the entire network. This paper proposes a framework of a decentralized e-government peer-to-peer (p2p) system using the blockchain technology, which can ensure both information security and privacy while simultaneously increasing the trust of the public sectors. In addition, a prototype of the proposed system is presented, with the support of a theoretical and qualitative analysis of the security and privacy implications of such system.

Overload control in the network domain of LTE/LTE-A based machine type communications

Abstract: It is expected that the LTE network, which includes the Radio Access Network (RAN) and the Core Network (CN) in 3GPP LTE systems, will be overloaded due to the huge number of Machine-Type Communication (MTC) devices in the near future. Overload in the RAN and CN of the LTE may result in congestion occurrence, resource waste, Quality of Service (QoS) degradation and in the worst-case, it will cause service unavailability. In this paper, we have proposed an adaptive mechanism to manage a large number of MTC devices in both RAN and CN of the LTE network. We use Access Class Barring (ACB) scheme to regulate the MTC traffic according to the congestions level in the RAN and CN. We consider a scenario in which two-priority-based classes of MTC devices are contending for the RAN resources. At first, the overload problem in the RAN is formulated to find the number of allowable contending MTC devices of each class taking into account their required QoS. Then, an active load management policy based on additive increase multiplicative decrease rule is proposed to control the incoming load from multiple cells to the CN. To effectively limit the number of MTC devices in both RAN and CN, in the proposed approach, each Evolved Node B updates the ACB factor upon overload detection in the RAN or CN in an adaptive manner. Simulation results show that the proposed mechanism is able to manage overload in the CN and RAN simultaneously.

Nature inspired discrete firefly algorithm for optimal mobile data gathering in wireless sensor networks

Abstract: Nowadays wireless sensor networks enhance the life of human beings by helping them through several applications like precision agriculture, health monitoring, landslide detection, pollution control, etc. The built-in sensors on a sensor node are used to measure the various events like temperature, vibration, gas emission, etc., in the remotely deployed unmanned environment. The limited energy constraint of the sensor node causes a huge impact on the lifetime of the deployed network. The data transmitted by each sensor node cause significant energy consumption and it has to be efficiently used to improve the lifetime of the network. The energy consumption can be reduced significantly by incorporating mobility on a sink node. Thus the mobile data gathering can result in reduced energy consumption among all sensor nodes while transmitting their data. A special mobile sink node named as the mobile data transporter (MDT) is introduced in this paper to collect the information from the sensor nodes by visiting each of them and finally it sends them to the base station. The Data collection by the MDT is formulated as a discrete optimization problem which is termed as a data gathering tour problem. To reduce the distance traveled by the MDT during its tour, a nature-inspired heuristic discrete firefly algorithm is proposed in this paper to optimally collect the data from the sensor nodes. The proposed algorithm computes an optimal order to visit the sensor nodes by the MDT to collect their data with minimal travel distance. The proposed algorithm is compared with tree-based data collection approaches and ant colony optimization approach. The results demonstrate that the proposed algorithm outperform other approaches minimizing the tour length under different scenarios.

MCFL: an energy efficient multi-clustering algorithm using fuzzy logic in wireless sensor network

Abstract: In this study, a multi-clustering algorithm based on fuzzy logic (MCFL) with an entirely different approach is presented to carry out node clustering in wsn. This approach minimizes energy dissipation and, consequently, prolongs network lifetime. In the past, numerous algorithms were tasked with clustering nodes in wireless sensors networks. The common denominator of all these approaches is the constancy of the algorithm in all the rounds of network lifetime that causes the selection of cluster heads in each round. Selecting cluster heads in each round indicates that throughout the process the most eligible nodes are not selected. By comparing the chance of each node to be selected as a cluster head using a random number, the majority of these clustering approaches, both fuzzy and non-fuzzy, destroy the chance of selecting the most eligible node as cluster head. As a result, all these approaches require the selection of cluster heads in each round. Performing selections in each round increases the rate of sent and received messages. By increasing the number of messages, the total number of sent messages in the network increases too. Therefore, in a network with a high number of nodes, any increase in the number of packets will augment network traffic and increase the collision probability. On the other hand, since nodes lose a certain amount of energy for each sent message, by increasing the number of messages, nodes’ energy will correspondingly decrease which results in their premature death. However, by selecting the most eligible nodes as cluster heads and trusting them for at least a few rounds, the amount of sent and received messages is reduced. In this article, In addition to clustering nodes in different rounds using different clustering algorithms, MCFL avoids selecting new cluster heads by trusting previous cluster heads leading to a reduction in the number of messages and saving energy. MCFL is compared with other approaches in three different scenarios using indices such as total remaining energy, the number of dead nodes, first node dies, half of nodes die, and last node dies. Results reveal that MCFL has as advantage over other approaches.

AODVCS, a new bio-inspired routing protocol based on cuckoo search algorithm for mobile ad hoc networks

Abstract: Mobile ad hoc networks (MANETs) are becoming an emerging technology that offer several advantages to users in terms of cost and ease of use. A MANET is a collection of mobile nodes connected by wireless links that form a temporary network topology that operates without a base station and centralized administration. Routing is a method through which information is forwarded from a transmitter to a specific recipient. Routing is a strategy that guarantees, at any time, the connection between any two nodes in a network. In this work, we propose a novel routing protocol inspired by the cuckoo search method. Our routing protocol is implemented using Network simulator 2. We chose Random WayPoint model as our mobility model. To validate our work, we opted for the comparison with the routing protocol ad hoc on-demand distance vector, destination sequence distance vector and the bio-inspired routing protocol AntHocNet in terms of the quality of service parameters: packet delivery ratio and end-to-end delay (E2ED).

A framework for social media data analytics using Elasticsearch and Kibana

Abstract: Real-time online data processing is quickly becoming an essential tool in the analysis of social media for political trends, advertising, public health awareness programs and policy making. Traditionally, processes associated with offline analysis are productive and efficient only when the data collection is a one-time process. Currently, cutting edge research requires real-time data analysis that comes with a set of challenges, particularly the efficiency of continuous data fetching within the context of present NoSQL and relational databases. In this paper, we demonstrate a solution to effectively adsress the challenges of real-time analysis using a configurable Elasticsearch search engine. We are using a distributed database architecture, pre-build indexing and standardizing the Elasticsearch framework for large scale text mining. The results from the query engine are visulized in almost real-time.

Contract design for relay incentive mechanism under dual asymmetric information in cooperative networks

Abstract: Cooperative relay network can effectively improve the wireless spectrum efficiency and extend the wireless network coverage. However, due to the selfish characteristics of wireless nodes, spontaneous cooperation among nodes is challenged. Moreover, wireless nodes may acquire the different network information with the various nodes’ location and mobility, channels’ conditions and other factors, which results in information asymmetry between the source and relay nodes. In this paper, the incentive issue between the relay nodes’ cooperative service and the source’s relay selection is investigated under the asymmetric information scenarios. By modeling cooperative communication as a labour market, a contract-theoretic model for relay incentive is proposed to achieve the twin objectives of ability-discrimination and effort-incentive. Considering the feature of asymmetric information, the static and dynamic information of the relay nodes are systematically discussed. To effectively incentivize the potential relay nodes to participate in cooperative communication, the optimization problems are formulated to maximize the source’s utility under the multiple information scenarios. A sequential optimization algorithm is proposed to obtain the optimal wage-bonus strategy with the low computational complexity under the dual asymmetric information scenario. Simulation results show that the optimal contract design scheme is effective in improving the performance of cooperative communication.

Sink-oriented tree based data dissemination protocol for mobile sinks wireless sensor networks

Abstract: Data dissemination toward static sinks causes the nearby nodes to deplete their energy quicker than the other nodes in the field (i.e., this is referred to as the hotspot problem). Accordingly, topology disruptions will occur and no data will be delivered to the sink. Mobile sinks are proposed to solve the hotspot problem in wireless sensor networks; they provide a load balancing and an energy consumption balancing for the whole network. However, sink mobility introduces new challenges (e.g., frequent location updates and packets delay). In this paper, we proposed a distributed sink-oriented dissemination protocol called Sink-oriented Tree based Data Dissemination (STDD). STDD constructs just one main dissemination tree for each mobile sink. When the access node is changed, the main tree will be updated and maintained to guarantee the shortest path to the mobile sinks. The updated and maintained tree is not a new tree; however, it is just a new version with only a few changes in a few levels of the main tree itself. Simulations show that STDD achieves a significant performance in terms of latency, network lifetime, delivery rate, and energy consumption compared with the state-of-the-art approaches.

Two-tier dynamic load balancing in SDN-enabled Wi-Fi networks

Abstract: This work proposes a Software Defined Networking (SDN) solution to address Wi-Fi congestion due to an unevenly distributed load among access points (APs). The conventional methods generally let client stations learn of APs’ load status and select APs distributively. However, such a client-driven approach lacks a global view to make precise load balancing decisions and may result in repeated changes in client-AP association. Although several studies proposed more efficient network-controlled methods to carry out Wi-Fi load balancing, some of them are distributed methods incurring excessive message exchange among customized APs, while the rest centralized methods are found to burden the central controller with unnecessary AP association decisions. In contrast, our solution adopts standardized OpenFlow protocol and SDN controller technology to Wi-Fi networks, organizing the SDN controller and the APs into a two-tier architecture so that the controller can evaluate the degree of load balancing among the APs and decide up to which load level the APs can accept association requests without consulting the controller. From our experiment results, our solution improves Wi-Fi’s load balancing degree by 34–41%, and yields an improvement of 28–36% in Wi-Fi’s re-association time over generic centralized load balancing methods with positive control.

A dynamic threshold based approach for mitigating black-hole attack in MANET

Abstract: Mobile ad-hoc network is an infrastructure less type of network which does not require any kind of fixed infrastructure. It provides multi-hop communication between the source and destination nodes which are not within the direct range of each other through the intermediate nodes. These intermediate nodes cooperate with other nodes in finding an optimum and shortest route toward the destination. However, in holistic environments, some nodes do not cooperate with other nodes in finding the optimal route towards the destination and intentionally give the false route information of having the shortest path toward the destination with a high destination sequence number in order to attract the traffic toward itself and start dropping of the data packets instead of forwarding it. This type of routing misbehaviour is generally called as black hole attack or full packet dropping attack which is one of the most severe destructive attacks that lead to the network degradation. In this paper, we have proposed a protocol called as Mitigating Black Hole effects through Detection and Prevention (MBDP-AODV) based on a dynamic threshold value of the destination sequence number. In order to validate the efficiency of proposed protocol, the NS-2.35 simulator is used. The simulation results show that proposed protocol performs better as compared with existing one under black hole attack.

Performance analysis of high-traffic cognitive radio communication system using hybrid spectrum access, prediction and monitoring techniques

Abstract: In this paper, the hybrid spectrum access and prediction techniques are exploited simultaneously in the high-traffic cognitive radio communication system, in order to enhance the throughput and overcome the problem of waiting states. The hybrid spectrum access is responsible for throughput enhancement by escaping the waiting states whereas the spectrum prediction alleviates the sensing errors in the high-traffic communication environment. The closed-form expression for the throughput of cognitive user (CU) communication is derived and validated the proposed approach with the reported literature. Moreover, a new framework is proposed to conquer the sharing issues of conventional and proposed approaches. In addition to this, the performance metrics of proposed framework such as the data-loss, energy-loss of the CU and interference at the PU have been analyzed.

Using wireless underground sensor networks for mine and miner safety

Abstract: Wireless sensor networks (WSNs) are a specific type of networks that link sensors and have the potential to greatly benefit monitoring of coal mine applications, underground mine safety and localization of miners. Such systems can monitor the underground environment in real-time, provide information about the localization of miners and production parameters thus enabling early warning. In this paper, the possibilities and limitations of using WSNs that can effectively operate in coal environments are investigated. In particular, the coal communication channel is modelled considering the propagation of electromagnetic (EM) waves in coal, the multipath effect and providing an evaluation about the bit error rate of the modelled channel depending on the coal type and depth. The propagation characteristics are investigated using a theoretical approach. More specifically, the paper sets the theoretical background for examining the path loss of EM waves propagating in coal in the MHz range and determines the incurred path loss. As a result the frequency window, which provides the best performance, has been determined in the 615 MHz band since compared to the 2.216 Ghz band it has a weaker dependence on both the molecular composition of the medium and the transmission distance in coal medium.

Multi-metric geographic routing for vehicular ad hoc networks

Abstract: Maintaining durable connectivity during data forwarding in Vehicular Ad hoc Networks has witnessed significant attention in the past few decades with the aim of supporting most modern applications of intelligent transportation systems. Various techniques for next hop vehicle selection have been suggested in the literature. Most of these techniques are based on selection of next hop vehicles from fixed forwarding region with two or three metrics including speed, distance and direction, and avoid many other parameters of urban environments. In this context, this paper proposes a Multi-metric Geographic Routing (M-GEDIR) technique for next hop selection. It selects next hop vehicles from dynamic forwarding regions, and considers major parameters of urban environments including, received signal strength, future position of vehicles, and critical area vehicles at the border of transmission range, apart from speed, distance and direction. The performance of M-GEDIR is evaluated carrying out simulations on realistic vehicular traffic environments. In the comparative performance evaluation, analysis of results highlight the benefit of the proposed geographic routing as compared to the state-of-the-art routing protocols.

Impact of the energy-based and location-based LEACH secondary cluster aggregation on WSN lifetime

Abstract: The improvement of sensor networks’ lifetime has been a major research challenge in recent years. This is because sensor nodes are battery powered and may be difficult to replace when deployed. Low energy adaptive clustering hierarchical (LEACH) routing protocol was proposed to prolong sensor nodes lifetime by dividing the network into clusters. In each cluster, a cluster head (CH) node receives and aggregates data from other nodes. However, CH nodes in LEACH are randomly elected which leads to a rapid loss of network energy. This energy loss occurs when the CH has a low energy level or when it is far from the BS. LEACH with two level cluster head (LEACH-TLCH) protocol deploys a secondary cluster head (2CH) to relieve the cluster head burden in these circumstances. However, in LEACH-TLCH the optimal distance of CH to base station (BS), and the choicest CH energy level for the 2CH to be deployed for achieving an optimal network lifetime was not considered. After a survey of related literature, we improved on LEACH-TLCH by investigating the conditions set to deploy the 2CH for an optimal network lifetime. Experiments were conducted to indicate how the 2CH impacts on the network at different CH energy levels and (or) CH distance to BS. This, is referred to as factor-based LEACH (FLEACH). Investigations in FLEACH show that as CHs gets farther from the BS, the use of a 2CH extends the network lifetime. Similarly, an increased lifetime also results as the CH energy decreases when the 2CH is deployed. We further propose FLEACH-E which uses a deterministic CH selection with the deployment of 2CH from the outset of network operation. Results show an improved performance over existing state-of-the-art homogeneous routing protocols.

Wireless fingerprinting indoor positioning using affinity propagation clustering methods

Abstract: According to rapid extension of wireless sensor network localization, indoor localization using fingerprint has turned out to be more considerable lately. It contains of a database called Receive Strength Signal Indicator vectors, which is a primitive amount in wireless sensor network fingerprinting positioning. The equivalence of a few strategies is brought up from the literary works, and some new variants are presented in this study. A combination of a clustering strategy named affinity propagation and statistical and probabilistic positioning procedures is considered in this review and at the same time, the impact of some components in our methodology onto positioning precision will be investigated. Affinity propagation clustering method set up a common baseline for assessing the relative accuracy of various indoor location methods effectively. Eventually two coarse localization methods as Mahalanobis norm method and similarity to exemplar receive strength signal vector are compared based on positioning accuracy and performance. Experimental outcomes prove that the intended algorithm will advance the accuracy and localization error compared with the method without clustering.

HOOSC: heterogeneous online/offline signcryption for the Internet of Things

Abstract: In order to improve the accessibility of the services provided by a sensor network, wireless sensor networks (WSNs) is integrated to Internet of Things (IoTs). In this case, the security is one of the issues be considered when integrating wireless sensor network to IoTs. In this paper, a heterogeneous secure scheme is proposed to build a secure channel between WSNs and Internet server in the IoTs. To achieve better security with minimum cost in WSNs, certificateless and online/offline technique are used. In addition, to increase the scalability at the Internet server side, public key infrastructure is used. As compared with four existing heterogeneous schemes, the proposed scheme has less energy consumption and computational cost. In addition, two application scenarios that illustrate how the proposed scheme can be applied in the IoTs have been given.