The Orphan Problem in ZigBee Wireless Networks

ZigBee is a communication standard which is considered to be suitable for wireless sensor networks. In ZigBee, a device (with a permanent 64-bit MAC address) is said to join a network if it can successfully obtain a 16-bit network address from a parent device. Parent devices calculate addresses for their child devices by a distributed address assignment scheme. This assignment is easy to implement, but it restricts the number of children of a device and the depth of the network. We observe that the ZigBee address assignment policy is too conservative, thus usually making the utilization of the address pool poor. Those devices that cannot receive network addresses will be isolated from the network and become orphan nodes. In this paper, we show that the orphan problem can be divided into two subproblems: the bounded-degree-and-depth tree formation (BDDTF) problem and the end-device maximum matching (EDMM) problem. We then propose algorithms to relieve the orphan problem. Our simulation results show that the proposed schemes can effectively reduce the number of orphan devices compared to the ZigBee strategy.     

A secure and low‐energy zone‐based wireless sensor networks routing protocol for pollution monitoring

Sensor networks can be used in many sorts of environments. The increase of pollution and carbon footprint are nowadays an important environmental problem. The use of sensors and sensor networks can help to make an early detection in order to mitigate their effect over the medium. The deployment of wireless sensor networks (WSNs) requires high‐energy efficiency and secures mechanisms to ensure the data veracity. Moreover, when WSNs are deployed in harsh environments, it is very difficult to recharge or replace the sensor's batteries. For this reason, the increase of network lifetime is highly desired. WSNs also work in unattended environments, which is vulnerable to different sort of attacks. Therefore, both energy efficiency and security must be considered in the development of routing protocols for WSNs. In this paper, we present a novel Secure and Low‐energy Zone‐based Routing Protocol (SeLeZoR) where the nodes of the WSN are split into zones and each zone is separated into clusters. Each cluster is controlled by a cluster head. Firstly, the information is securely sent to the zone‐head using a secret key; then, the zone‐head sends the data to the base station using the secure and energy efficient mechanism. This paper demonstrates that SeLeZoR achieves better energy efficiency and security levels than existing routing protocols for WSNs. Copyright © 2016 John Wiley & Sons, Ltd.     

HDF: Hybrid Debugging Framework for Distributed Network Environments

Debugging in distributed environments, such as wireless sensor networks (WSNs), which consist of sensor nodes with limited resources, is an iterative and occasionally laborious process for programmers. In sensor networks, it is not easy to find unintended bugs that arise during development and deployment, and that are due to a lack of visibility into the nodes and a dearth of effective debugging tools. Most sensor network debugging tools are not provided with effective facilities such as real‐time tracing, remote debugging, or a GUI environment. In this paper, we present a hybrid debugging framework (HDF) that works on WSNs. This framework supports query‐based monitoring and real‐time tracing on sensor nodes. The monitoring supports commands to manage/control the deployed nodes, and provides new debug commands. To do so, we devised a debugging device called a Docking Debug‐Box (D2‐Box), and two program agents. In addition, we provide a scalable node monitor to enable all deployed nodes for viewing. To transmit and collect their data or information reliably, all nodes are connected using a scalable node monitor applied through the Internet. Therefore, the suggested framework in theory does not increase the network traffic for debugging on WSNs, and the traffic complexity is nearly O(1).     

Deploying wireless sensor networks–based smart grid for smart meters monitoring and control

Transmission and distribution systems for electricity have undergone a technological revolution in terms of operation and management using computer networks, automation, remote sensing, and information and communication technologies to improve the performance of digital electronic meters. This work describes the integration of a wireless sensor networks (WSNs)–based communication system with an electrical energy‐measurement structure, to verify the feasibility of large‐scale installation of intelligent electronic meters in low‐voltage consumer units. The study is based on simulations, using Castalia, considering 2 scenarios, the first in a flat network and the second in a hierarchical network of WSNs to analyze the feasibility of sending messages from intelligent electronic meters to the concessionaires through a ZigBee network.In addition, the time requirements of the IEC 61850 standard for sending and receiving manufacturing message specifications and generic object‐oriented substation event type messages are verified. This work demonstrated the technical feasibility of using WSNs for different node densities by region and evaluated the location of the sink node, and adequate infrastructures for WSNs were found. This extends time checks for both vertical (usually for supervision) and horizontal (used for protection) messages. The proposed model has great potential to use a WSN infrastructure and to evaluate if this infrastructure allows data transmission of the protocols used in smart grids, mainly verifying the requirements of transmission times required by each application.     

Energy‐efficient multi‐level and distance‐aware clustering mechanism for WSNs

Most sensor networks are deployed at hostile environments to sense and gather specific information. As sensor nodes have battery constraints, therefore, the research community is trying to propose energy‐efficient solutions for wireless sensor networks (WSNs) to prolong the lifetime of the network. In this paper, we propose an energy‐efficient multi‐level and distance‐aware clustering (EEMDC) mechanism for WSNs. In this mechanism, the area of the network is divided into three logical layers, which depends upon the hop‐count‐based distance from the base station. The simulation outcomes show that EEMDC is more energy efficient than other existing conventional approaches. Copyright © 2013 John Wiley & Sons, Ltd.     

Securing a wireless sensor network for human tracking: a review of solutions

Currently, wireless sensor networks (WSNs) are formed by devices with limited resources and limited power energy availability. Thanks to their cost effectiveness, flexibility, and ease of deployment, wireless sensor networks have been applied to many scenarios such as industrial, civil, and military applications. For many applications, security is a primary issue, but this produces an extra energy cost. Thus, in real applications, a trade‐off is required between the security level and energy consumption. This paper evaluates different security schemes applied to human tracking applications, based on a real‐case scenario. Copyright © 2013 John Wiley & Sons, Ltd.     

PSAR: power-source-aware routing in ZigBee networks

ZigBee is a recent wireless networking technology built on IEEE 802.15.4 standard and designed especially for low-data rate and low-duty cycle applications such as home and building automation and sensor networks. One of the primary goals of ZigBee is low power consumption and therefore long-living networks. Despite this goal, current network formation and routing protocols described in the ZigBee specification do not fully address power consumption issues. In this work, we propose a distributed routing algorithm to reduce power consumption of battery-powered devices by routing the communication through mains-powered devices whenever possible and consequently increasing the overall network lifetime. The proposed algorithm works on tree topologies supported by ZigBee and requires only minor modifications to the current specification. Our ns-2 simulation results showed that the algorithm is able to reduce the power consumption of battery-powered devices significantly with minimal communication overhead.     

A Strong Authentication Scheme with User Privacy for Wireless Sensor Networks

Wireless sensor networks (WSNs) are used for many real‐time applications. User authentication is an important security service for WSNs to ensure only legitimate users can access the sensor data within the network. In 2012, Yoo and others proposed a security‐performance‐balanced user authentication scheme for WSNs, which is an enhancement of existing schemes. In this paper, we show that Yoo and others' scheme has security flaws, and it is not efficient for real WSNs. In addition, this paper proposes a new strong authentication scheme with user privacy for WSNs. The proposed scheme not only achieves end‐party mutual authentication (that is, between the user and the sensor node) but also establishes a dynamic session key. The proposed scheme preserves the security features of Yoo and others' scheme and other existing schemes and provides more practical security services. Additionally, the efficiency of the proposed scheme is more appropriate for real‐world WSNs applications.     

Lifetime enhancement of wireless sensor networks by avoiding energy-holes with Gaussian distribution

Wireless sensor networks (WSNs) are receiving significant attention due to their potential applications in environmental monitoring and surveillance domains. In WSNs, preserving energy requires utmost attention, as they are highly resource constrained. One fundamental way of conserving energy is judicious deployment of nodes within the network for balancing energy flow throughout the network. Node deployment using Gaussian distribution is a standard practice and is widely acceptable when random deployment is used. Initially, an analysis is done to establish that Gaussian distribution based node deployment is not energy balanced. Standard deviation of Gaussian distribution is identified as the parameter responsible for energy balancing. A deployment strategy is proposed for energy balancing using customized Gaussian distribution by discretizing the standard deviation. Performance of the scheme is evaluated in terms of energy balance and network lifetime. Exhaustive simulation is performed to measure the extent of achieving our design goal of enhancing network lifetime while attaining energy balancing. The simulation results show that our scheme also provides satisfactory network performance in terms of end-to-end delay and throughput. Finally, all the results are compared with three competing schemes and the results confirm our scheme’s supremacy in terms of both design performance metrics as well as network performance metrics.     

A review on solar forecasting and power management approaches for energy‐harvesting wireless sensor networks

For rechargeable wireless sensor nodes, effective power management is of prime importance because of the stochastic behaviour of the environmental resources. A key issue in integrating solar resources with wireless sensor networks (WSNs) is the need of precise irradiance measurements and power to resource modelling. WSNs are employed in an adhoc manner comprises of numerous sensing nodes and organised as a network for the sake of checking and balancing the environmental factors. Each node has sensing, computation, communication, and locomotion capabilities but operates with limited battery life. Energy harvesting is a way of powering these WSNs by harvesting energy from the environment. By considering harvested energy as an energy source, certain considerations are different from that of battery‐operated networks. Nondeterministic energy availability with respect to time is the reason behind these differences, which put a limit on the maximum rate at which energy can be used. Thus, reliable knowledge of solar radiation is essential for informed design, deployment planning, and optimal management of energy in rechargeable WSNs. Further, power management is essential in self‐powerssed networks to efficiently utilize the available energy. In this paper, a detailed survey on different solar forecasting techniques has been presented for precise energy estimates. A detailed study on energy efficient power management techniques is also proposed to address the feasibility of energy‐harvesting approach in WSNs.     

Accelerating signature-based broadcast authentication for wireless sensor networks

In wireless sensor networks (WSNs), broadcast authentication is a crucial security mechanism that allows a multitude of legitimate users to join in and disseminate messages into the networks in a dynamic and authenticated way. During the past few years, several public-key based multi-user broadcast authentication schemes have been proposed to achieve immediate authentication and to address the security vulnerability intrinsic to μTESLA-like schemes. Unfortunately, the relatively slow signature verification in signature-based broadcast authentication has also incurred a series of problems such as high energy consumption and long verification delay. In this contribution, we propose an efficient technique to accelerate the signature verification in WSNs through the cooperation among sensor nodes. By allowing some sensor nodes to release the intermediate computation results to their neighbors during the signature verification, a large number of sensor nodes can accelerate their signature verification process significantly. When applying our faster signature verification technique to the broadcast authentication in a 4 × 4 grid-based WSN, a quantitative performance analysis shows that our scheme needs 17.7-34.5% less energy and runs about 50% faster than the traditional signature verification method. The efficiency of the proposed technique has been tested through an experimental study on a network of MICAz motes.     

Gravitational outlier detection for wireless sensor networks

Accuracy of sensed data and reliable delivery are the key concerns in addition to several other network‐related issues in wireless sensor networks (WSNs). Early detection of outliers reduces subsequent unwanted transmissions, thus preserving network resources. Recent techniques on outlier detection in WSNs are computationally expensive and based on message exchange. Message exchange‐based techniques incur communication overhead and are less preferred in WSNs. On the other hand, machine learning‐based outlier detection techniques are computationally expensive for resource constraint sensor nodes. The novelty of this paper is that it proposes a simple, non message exchange based, in‐network, real‐time outlier detection algorithm based on Newton's law of gravity. The mechanism is evaluated for its accuracy in detecting outliers, computational cost, and its influence on the network traffic and delay. The outlier detection mechanism resulted in almost 100% detection accuracy. Because the mechanism involves no message exchanges, there is a significant reduction in network traffic, energy consumption and end‐to‐end delay. An extension of the proposed algorithm for transient data sets is proposed, and analytic evaluation justifies that the mechanism is reactive to time series data. Copyright © 2016 John Wiley & Sons, Ltd.     

一种基于冗余度的无线传感器网络节能策略

在无线传感器网络中,传感节点由于采用电池供电,因此寿命有限。如何有效节省传感器节点的能量,延长网络的使用寿命,一直是广泛研究的焦点。文章提出一种适用于高冗余度布置的无线传感器网络结构中,节省传感器节点能量消耗的方法-接续调度法。该方法通过协调点对小区域内节点的调度,使区域内节点依次分时段工作。通过这种接续调度,避免了节点间的冲突和串扰,达到延长整体网络寿命的效果。     

A frequency‐aware data‐centric mechanism for wireless sensor networks

Wireless sensor networks (WSNs) are characterized by their low bandwidth, limited energy, and largely distributed deployment. To reduce the flooding overhead raised by transmitting query and data information, several data‐centric storage (DCS) mechanisms are proposed. However, the locations of these data‐centric nodes significantly impact the power consumption and efficiency for information queries and storage capabilities, especially in a multi‐sink environment. This paper proposes a novel dissemination approach, which is namely the dynamic data‐centric routing and storage mechanism (DDCRS), to dynamically determine locations of data‐centric nodes according to sink nodes' location and data collecting rate and automatically construct shared paths from data‐centric nodes to multiple sinks. To save the power consumption, the data‐centric node is changed when new sink nodes participate when the WSNs or some queries change their frequencies. The simulation results reveal that the proposed protocol outperforms existing protocols in terms of power conservation and power balancing. Copyright © 2009 John Wiley & Sons, Ltd.     

An Improved Delay Resistant Adaptive Multicasting Strategy for High Definition Video Delivery in Wireless Overlay Network

Wireless Personal Communications - Wireless sensor networks (WSNs) incorporate small devices known as sensors. These sensors monitor the deployment field and are responsible for communicating the...     

GSHMAC: Green and Secure Hybrid Medium Access Control for Wireless Sensor Network

The cost efficiency of wireless platforms and their easy deployment enable the applicability of it in widespread application domains. Wireless sensor networks (WSNs) are not excluded from it. Their application domains vary from industrial monitoring to military applications. A WSN is a resource-constrained network and energy of the WSN node is a valuable resource. Like every other network, WSNs are also vulnerable to security attacks. A security attack can results in networks consuming more resources, leading to earlier depletion of node energy. A significant part of the resource consumption in a WSN is controlled by the medium access control (MAC) mechanism. This paper focuses on WSN MAC mechanisms and countermeasures for attacks targeting the MAC layer in a WSN. Denial of sleep attacks are the most relevant for WSN MAC as these types of attacks have shattered effects, which bring down the sensor lifetime from years to days. This paper proposes a secure hybrid MAC mechanism, Green and Secure Hybrid Medium Access Control (GSHMAC) to overcome the devastating effect of WSN MAC attacks. The proposed mechanism provides features such as collision threshold-based MAC mode control and countermeasures on WSN MAC using internal MAC mechanisms. GSHMAC shows improved energy-efficiency, delay, and throughput in the presence of attacks, as compared with state-of-art secure MAC mechanisms.     

A joint resource allocation‐channel coding design based on distributed source coding

Wireless sensor networks (WSNs) have found a wide variety of applications recently. However, the challenges in WSNs still remain in improving the sensor energy efficiency and information quality (distortion reduction) of the sensing data transmissions. In this paper, we propose a novel cross‐layer design of resource allocation and channel coding to protect distributed source coding (DSC)‐based data transmission. Resource allocation strategies include rate adaptation and automatic repeat‐request retransmissions. Our proposed joint design of resource allocation, channel coding, and DSC can improve the network energy efficiency and information quality while meeting the data transmission latency requirements. Further, we investigate how the resource allocation enables the network to achieve unequal error protection among correlated DSC streams. Our simulation studies demonstrate that the proposed joint design significantly improves the DSC‐based data transmission quality and the network energy efficiency. Copyright © 2013 John Wiley & Sons, Ltd.     

A Detailed Review of Multi-Channel Medium Access Control Protocols for Wireless Sensor Networks

Most applications of Wireless Sensor Networks (WSNs) assume the presence of single-channel Medium Access Control (MAC) protocols. In the usual dense deployment of the sensor networks, single-channel MAC protocols may be deficient because of radio collisions and limited bandwidth. Hence, using multiple channels can significantly improve the performance of WSN. Recent developments in sensor technology, as seen in Crossbow’s MICAz Mote, Rockwell’s WINS nodes and IEEE 802.15.4 Zigbee, have enabled support for multi-channel communications. Several multi-channel MAC protocols with different objectives have been proposed for WSNs in literature. This paper surveys and classifies the state-of-the-art multi-channel MAC protocols that are proposed for WSNs. It first outlines the sensor network properties that are crucial for designing a MAC protocol. It subsequently reviews the existent challenges to design a good multi-channel MAC protocol for the sensor networks. Then, several multi-channel MAC protocols specifically proposed for the WSNs are inspected in detail and compared with each other. Finally, some open issues in this area are outlined for future research.     

Efficient clusterhead rotation via domatic partition in self‐organizing sensor networks

Nodes in wireless sensor networks (WSN) are deployed in an unattended environment with non re‐chargeable batteries. Thus, energy efficiency becomes a major design goals in WSNs. Clustering becomes an effective technique for optimization energy in various applications like data gathering. Although aggregation aware clustering addresses lifetime and scalability goals, but suffers from excessive energy overhead at clusterhead nodes. Load balancing in existing clustering schemes often use rotation of clusterhead roles among all nodes in order to prevent any single node from complete energy exhaustion. We considered important aspects of energy and time overhead in rotation of the clusterhead roles in various node clustering algorithms with goals to further prolong the network lifetime by minimizing the energy overheads in rotation setup. The problem of clusterhead rotation is abstracted as the graph‐theoretic problem of domatic partitioning, which is also NP‐complete. The dense deployment and unattended nature rules out the possibility of manual or external control in existing domatic partition (DP) techniques to be used for WSNs. To our knowledge, no self‐organizing technique exists for domatic partitioning. We developed a distributed self‐organizing one‐domatic partitioning scheme with approximation factor of at least 1/16 for unit‐disk‐graphs (UDGs). In this work, we demonstrate that the benefits of self‐organization is achieved without sacrificing the quality of domatic partitioning. We demonstrated through simulations that our self‐organizing DP without sacrificing on the size of DP achieves self‐organization capability which is able to reduce time and energy overheads of clusterhead rotation resulting to an improved network lifetime compared to the existing clustering protocols for sensor networks. Copyright © 2008 John Wiley & Sons, Ltd.     

DUCR: Distributed unequal cluster‐based routing algorithm for heterogeneous wireless sensor networks

Designing energy efficient communication protocols for wireless sensor networks (WSNs) to conserve the sensors' energy is one of the prime concerns. Clustering in WSNs significantly reduces the energy consumption in which the nodes are organized in clusters, each having a cluster head (CH). The CHs collect data from their cluster members and transmit it to the base station via a single or multihop communication. The main issue in such mechanism is how to associate the nodes to CHs and how to route the data of CHs so that the overall load on CHs are balanced. Since the sensor nodes operate autonomously, the methods designed for WSNs should be of distributed nature, i.e., each node should run it using its local information only. Considering these issues, we propose a distributed multiobjective‐based clustering method to assign a sensor node to appropriate CH so that the load is balanced. We also propose an energy‐efficient routing algorithm to balance the relay load among the CHs. In case any CH dies, we propose a recovery strategy for its cluster members. All our proposed methods are completely distributed in nature. Simulation results demonstrate the efficiency of the proposed algorithm in terms of energy consumption and hence prolonging the network lifetime. We compare the performance of the proposed algorithm with some existing algorithms in terms of number of alive nodes, network lifetime, energy efficiency, and energy population.