Scoping in wireless sensor networks

Wireless sensor networks (WSN) have specific constraints and stringent requirements in contrast to traditional wired and wireless computer networks. Among these specific requirements, energy-efficiency is the most prominent. Sensor motes have finite amount of energy supply. In most WSN applications, hundreds or thousands of motes are deployed in an area (e.g., behind enemy lines or foliage) and there is no provision for battery recharging. Therefore, a fundamental constraint on WSN applications and services is to extend the network's lifetime by making the batteries run longer. In this paper we propose an energy-efficient time synchronization protocol, referred as ETSP, which gives significant improvement in energy consumption over existing time synchronization schemes. We first evaluate the existing reference broadcast synchronization (RBS) and time-sync protocol for sensor networks (TPSN), which are two prominent examples of receiver-receiver and sender-receiver synchronization methods. This performance analysis demonstrates that combination of RBS and TPSN can work better than using these techniques separately. In the proposed ETSP protocol, we identify conditions to toggle between RBS and TPSN based on a threshold value. We experimentally and mathematically derive an optimal value of the switching threshold for different sensor motes. In this way we effectively reduce the number of transmissions which results in saving energy. Moreover, we assess the performance of our protocol on the bit error traces collected over a real WSN test bed to cater for retransmissions overload for the time synchronization protocols under consideration.

Internet of Things (IOT) is experiencing a super-fast growing phase. Wireless Sensor Networks (WSN), as the “five sense organs” and teleneuron of IOT, is developing fast along. Owing to the application-oriented characteristics of WSN, WSN applications may differ enormously in implementation methods. The WSN developers may have to rewrite the code for each and every application. Along with the increasing demand to WSN applications, WSN developers may have heavier tasks of programming for these applications. Thanks to TinyOS and NesC, an operating system and programming language designed especially for WSN, raises the WSN application's programming to a higher level. Large number of supported sensor hardware plus system provided and user-de-fined libraries eases WSN application programmers' jobs. How-ever, the massive amount of nodes' communication and networking, and security protection slows down the development pace. A unified and empirical WSN application implementation platform is one of the available solutions to the problem. This paper introduces an empirical WSN application implementation platform, which avails the WSN developers build an application with unified code template and network packet generation and processing strategies.

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.

Wireless sensor networks consist of a large number of low-cost, low-power, and multifunctional sensor nodes that communicate over short distances through wireless links. Such sensor networks are ideal candidates for a wide range of applications such as monitoring of critical infrastructures, data acquisition in hazardous environments, industry control systems, vehicular networks, and military operations. Wireless sensor networks introduce new security challenges due to their dynamic topology, severe resource constraints, and absence of a trusted infrastructure. The purpose of this special issue is to publish high-quality research papers as well as review articles addressing recent advances of wireless sensor network security. In this special issue, we will explore the topic of security challenges and solutions for the wide application of wireless sensor networks in different areas, such as RFID and smart grid. RFID has been widely used in logistics and internet of things. Smart grid leverages sensor networks to better balance the load of the power grid. Both of them have great impact on the daily life and areweak points of thewhole economy,which attract the attention of terrorists. The feasible attacks and defense solutions are still not clear.The papers in this volume also cover several important foundational security services for wireless sensor networks, such as key management, key distribution, secure cluster formation, secure architecture for multihop communication, intrusion prediction, and secure localization. All these foundational security services are critical bases for application of wireless sensor networks. We hope that the papers in this volume engender further thinking about new security challenges for wireless sensor networks and even further “out-of-the-box” ideas about how to solve new security problems for wireless sensor networks.

Wireless network of wearable biomedical sensors by human body shows great potential to enhance the biometrics performance significantly. Meanwhile, it poses prominent characteristics and challenges to physicians and engineers for its particular medical application as compared to other application of wireless sensor networks (WSN). Mobility pattern plays an important role in designing the wireless body sensor networks (WBSN) and will also affect the accuracy of modeling WBSN in health care application. Much of the mobility scenarios generated in current work of wireless body sensor networks has used fairly simple models to generate the mobile topological graph, which bear little resemblance to the actual mobility patterns. This paper is the first attempt to investigate the mobility model in WBSN based on the existing mobility models in wireless data networks and ad hoc networks. We first briefly review the existing mobility models in related research areas such as wireless ad hoc network and cellular networks. Further on, we propose a dedicated and more realistic mobility model named BAMM (Body Area Mobility Model) for wireless body sensor networks by concentrating on the unique characteristics of WBSN and finally study the effects of mobility on the performance of WBSN by simulation experiments.

Wireless sensor networks (WSNs) consist of a large number of small, low data rate and inexpensive nodes that communicate in order to sense or control a physical phenomenon. The major difference between the WSN and the traditional wireless network is that sensors are very sensitive to energy consumption. Moreover, the performance of the sensor network applications highly depends on the lifetime of the network and we expect the lifetime of several months to several years. Thus, energy saving is crucial in designing long-lived wireless sensor networks. Many researchers have focused on developing energy efficient cluster based protocols for WSNs, but there has not been much research on event driven WSNs and, their focus is on continuous driven networks. In this paper, we propose a modified algorithm of Low Energy Adaptive Clustering Hierarchy (LEACH) protocol which is a well known energy efficient clustering algorithm for WSNs. Our modified protocol called “Adaptive and Energy Efficient Clustering Algorithm for Event-Driven Application in Wireless Sensor Networks (AEEC)” is aimed at prolonging the lifetime of a sensor network by balancing energy usage of the nodes. AEEC makes the nodes with more residual energy have more chances to be selected as cluster head. Also, we use elector nodes which take the responsibility of collecting energy information of the nearest sensor nodes and selecting the cluster head. We compared the performance of our AEEC algorithm with the LEACH protocol using simulations .

We present a case study that considers the application of runtime verification technology to a wireless sensor application. The case study is performed using the SURGE TinyOS application for multi-hop routing, which executes on the Avrora TinyOS simulator. We discuss the problems we have encountered in the course of case study. The problems include unclear correctness properties for wireless network applications (indicating ad hoc development process) and inadequate tool support. A wireless sensor network usually comprises of a collection of tiny devices with built-in processors that can gather physical and environment information such as temperature, light, sound, etc., and communicate with one another over radio. Many wireless sensor network applications sit on top of an operating system called TinyOS and are mostly written in nesC, an extension of C that provides a component-based programming paradigm. Most of wireless sensor network applications are developed and tested on a simulator before they are deployed in the environment because testing and debugging directly on physical devices are very difficult, especially when the network consists of many nodes, and may not provide enough information for debugging. A simulator usually produces detailed execution information and can help find errors. However, even with the simulator and nesC, the current state of development tools for wireless sensor network still requires very low-level programming, which makes it hard for the developers to maintain a high-level view of the system operation. During the validation stage, lack of sophisticated debugging tools for sensor networks makes it difficult to make the connection between a high-level functional or performance requirement and a particular aspect of system implementation. This paper investigates a high-level approach to examine execution data from a simulator and analyze it using runtime verification. The technique 1) identifies and formally specifies high-level requirements for the system under development, 2) monitors a distributed wireless sensor network application using data provided by the simulator, and 3) checks for timing and dynamic properties to gain understanding of the relevant behaviors of wireless sensor nodes and to provide a systematic approach in finding bugs and errors. A particular runtime verification used inthis paper is MaC. MaC provides specification languages capable of expressing functional, timing, and probabilistic properties to specify requirements or patterns of errors. Properties can, for example, examine periodic behaviors or identify a faulty node. MaC then monitors and checks a wireless sensor network application against its specification by observing data produced by a simulator. The motivation for applying the monitoring and checking technique to check wireless sensor network applications is threefold: 1) raise the development level for wireless sensor network, 2) provide a mechanism for understanding high-level behaviors of the system in terms of low-level observation, and 3) provide a tool based on the acceptance of the state of the art development tool for sensor networks.

Monitoring and automatic control of building environment is a crucial application of Wireless Sensor Network (WSN) in which maximizing network lifetime is a key challenge. Previous research into the performance of a network in a building environment has been concerned with radio propagation within a single floor. We investigate the link quality distribution to obtain full coverage of signal strength in a four-storey building environment, experimentally. Our results indicate that the transitional region is of particular concern in wireless sensor network since it accommodates high variance unreliable links. The transitional region in a multi-storey building is mainly due to the presence of reinforced concrete slabs at each storey and the fac┬©ade which obstructs the radio signal and introduces an additional absorption term to the path loss.

Resource Management Approach to an Efficient Wireless Sensor Network

For mission-critical applications of wireless sensor networks (WSNs) involving extensive battlefield surveillance, medical healthcare, etc., it is crucial to have low-power, new protocols, methodologies and structures for transferring data and information in a network with full sensing coverage capability for an extended working period. The upmost mission is to ensure that the network is fully functional providing reliable transmission of the sensed data without the risk of data loss. WSNs have been applied to various types of mission-critical applications. Coverage preservation is one of the most essential functions to guarantee quality of service (QoS) in WSNs. However, a tradeoff exists between sensing coverage and network lifetime due to the limited energy supplies of sensor nodes. In this study, we propose a routing protocol to accommodate both energy-balance and coverage-preservation for sensor nodes in WSNs. The energy consumption for radio transmissions and the residual energy over the network are taken into account when the proposed protocol determines an energy-efficient route for a packet. The simulation results demonstrate that the proposed protocol is able to increase the duration of the on-duty network and provide up to 98.3% and 85.7% of extra service time with 100% sensing coverage ratio comparing with LEACH and the LEACH-Coverage-U protocols, respectively.

Congestion in Wireless Sensor Network (WSN) occurs when traffic load allocated to any sensor node is beyond its capacity. It is necessary to control the congestion traffic to support traditional quality of service (such as packet loss ratios, packet delay, wasting energy and throughput) especially, multimedia application of Wireless Multimedia Sensor Network (WMSN). Congestion control in WSN has been shown to be very effective with respect to extending lifespan of system. Hence to avoid the congestion in WSN, we proposed an efficient protocol called Priority-based Congestion Control Protocol (PCCP) which prevents an upstream congestion in WSN. The PCCP creates priority table based an importance of each node, and then sends this information to all the nodes within the network. Secondly, the major function of PCCP is to measure congestion level in the network using ratio of packet inter-arrival time along over packet service time. PCCP uses to control upstream congestion along with congestion degree and packet table. PCCP is hop-by-hop upstream congestion control protocol for WSN. PCCP provides work for packet-based computation to optimize congestion control. It can work under both single path & multipath routing. PCCP ensures guarantee of packet loss as well as delay, resulting each node can avoid unfairness and achieve flexible throughput. In this paper, we have proposed that PCCP provides better QoS by controlling network recourse management and network traffic to consuming efficient energy.

With the advancement of wireless sensor networks (WSNs) and technology, applicability of WSNs as a system is touching new heights. The development of multimedia nodes has led to the creation of another intelligent distributed system, which can transfer real-time multimedia traffic, ubiquitously. Wireless multimedia sensor networks (WMSNs) are applicable in a wide range of areas including area monitoring and video surveillance. But due to unreliable error-prone communication medium and application specific quality of service (QoS) requirements, routing of real-time multimedia traffic in WMSNs poses a serious problem. The paper discusses various existing routing strategies in WMSNs, with their properties and limitations which lead to open research issues. Further, detailed classification and analytical comparison of discussed protocols are also presented.

Using wireless sensor networks (WSNs) in delay and reliability critical environments is highly desired due to their unique advantages such as low cost, ease of deployment, and redundancy. However, successful deployment of resource-limited WSNs in such applications requires strict quality-of-service (QoS) provisioning techniques to meet the desired latency and reliability targets of those applications. Implementation of QoS techniques in WSNs is significantly challenging since WSNs have been initially devised for low-data-rate non-real-time applications. Therefore, WSN designers and developers resort to different cross-layer interaction and optimization techniques to provision QoS in WSNs. In this paper, we present a survey on the state of the art of cross-layer QoS approaches in wireless terrestrial sensor networks to achieve delay and reliability bounds in critical applications. Our paper provides a unique classification of cross-layer QoS approaches in WSNs that allows surveying a large amount of studies with utmost clarity. Furthermore, we highlight the main challenges of implementing QoS protocols in WSNs and present an overview of QoS-aware WSN applications.

Wireless Sensor Network (WSN) technology has the potential to have impact on many aspects of Precision Agriculture (PA). However, current WSN applications in Precision Agriculture all adopt the traditional client/sever model, data are sent from the source to the destination, because of hugeous data, high concurrency and strong signal interference in Precision Agriculture and the extremely limited sensor network resources, such client/sever model hampers WSN applications in Precision Agriculture.[ This paper presents a mobile-based agent of wireless sensor network model MAPA, MAPA avoids the large agricultural intermediate data transmission through migrating the computing to the resource source, and consequently it prolongs the sensor network lifetime and promotes the WSN applications in Precision Agriculture.

THE USE OF WIRELESS SENSOR NETWORKS IN AGRICULTUTE A TOOL FOR A SUSTAINABLE FOOD SUPPLY IN THE ARAB WORLD In this paper some ideas of how to apply the technological advancement of the wireless sensor networks (WSN) in agriculture as a tool for food security is discussed. This will include some examples where the technology can be applied, what changes can this technology brings to the traditional farming, which can help within the solution of the Arab World food security problems. This will help the region to develop and be part of the global strategy for the World food security. WSN features of having a low power consummation nature with different options of using different energy sources will make it as the just technology suitable in a remote and less or without infrastructural bases environment for many countries within the region. The applications of WSN which are suitable for the purpose will be discussed. Keywords: WSN, Food Security, Agriculture in Arab region, WSN Farmer Kits Tool, Energy Sources. Introduction Arabic countries are naturally rich, many countries within the region have a wide virgin land. But unfortunately some of these countries have been a focus in term of food shortages for long time which cause by many factors like land degradation, water crisis, land deals, climate change, agricultural disease, governing system, wars, population growth, land use change, living style change, high prices and lack of technology. As technology has rational parts in solving the most difficult problems for today's society, WSN can be applied in agriculture to reduce or solve this problem. Use of WSN in Agriculture as a solution As traditional farming is the lead in the region, people use their own human sense to perceive the surrounding to investigate the soil and predict the weather. But the remote sensing of the WSN as an activity of recording, observing, perceiving objects or events, wirelessly these happenings are processes and analyzed in a real time. The idea of applying this technology is to be adopted in different applications shortly can be said here. *Soil Investigation by using the specialized soil test sensor detectors to determine the fertility of soil nutrient deficiencies, elements like Nitrogen is very important for plants. *Weather Prediction by using a web data from WSN can be transmitted enabling a remote online interactive retrieval access, and then these data can be shared with the farmers. *Detection of ground water using WSN the level and the amount of sufficient water can be detected before planting. *Using the WSN the water and the area can be controlled during irrigation which will help in reducing the energy consumption. *Food storage system will be advanced by the use of WSN in knowing usage validity time and the space of storing. *Knowing where how and when to deliver what kind of product by using WSN will help in the logistical distribution of crops. *Farming Dissemination by using an integrated WSN tool kit messages can be disseminated.