Wireless Sensor Network for Underground Mining Services Applications

Underground mines include a number of challenges due to their hostile milieu. Therefore, geotechnical and environmental monitoring mainly in underground coal mines have always been a critical task to ensure safe working conditions. If the monitoring device is cable based, then it requires an huge amount of cable deployment which can pose not only the high maintenance cost but difficulty in laying out the cable throughout the underground galleries. on the other hand, if it is direct wireless communication between sensing devices and the central processing unit, it is also not so feasible due to the crisscross, uneven and incline path. Therefore, Wireless Sensor Networks grab an opportunity to be deployed in such a hostile environment. Keeping in view, in the present chapter, attempts have been made to discuss the different aspects of wireless sensor network for underground coal mining services applications to overcome the various threats. Further, the best suited logical topology has been identified for the same.

Media Access Control Protocols for Healthcare Sensor Networks

The advancement of information and communication technology directly influences the life style of human being by making their life easier, sophisticated in many circumstances. The healthcare sensor network is one of the emerging areas of research for both computer science and health professionals. The Quality of Service (QoS) requirement of the traffic in emergency situation is one of the key challenges in this network. The Medium Access Control (MAC) layer plays vital role for reliable and on time delivery in the healthcare sensor networks. The healthcare system provides remote monitoring, real-time identification and control information which helps in identifying the unusual patterns and making more precise information about the situation. In this chapter, we present the issues and challenges of supporting sensor networks for healthcare applications. Then we present an extensive survey of MAC protocols developed to address the major challenges and improve the capacity of healthcare system in WSN.

Sensor Data Geographic Forwarding in Two-Dimensional and Three-Dimensional Spaces

A wireless sensor network is a collection of sensor nodes that have the ability to sense phenomena in a given environment and collect data, perform computation on the gathered data, and transmit (or forward) it to their destination. Unfortunately, these sensor nodes have limited power, computational, and storage capabilities. These factors have an influence on the design of wireless sensor networks and make it more challenging. In order to overcome these limitations, various power management techniques and energy-efficient protocols have been designed. Among such techniques and protocols, geographic routing is one of the most efficient ways to solve some of the design issues. Geographic routing in wireless sensor networks uses location information of the sensor nodes to define a path from source to destination without having to build a network topology. In this paper, we present a survey of the existing geographic routing techniques both in two-dimensional (2D) and three-dimensional (3D) spaces. Furthermore, we will study the advantages of each routing technique and provide a discussion based on their practical possibility of deployment.

Handover in Mobile WiMAX

WiMAX (Worldwide Interoperability for Microwave Access) is a core technology based on IEEE 802.16 standard for Broadband Wireless Access (BWA). One of the major consideration for Mobile WiMAX is seamless handoff or handover. Cellular-based standards have the facility of voice call even via internet but to deal handover with mobility is a challenging task. Many services like Voice over Internet Protocol (VoIP), Virtual Private Networks (VPNs), etc. require the presence of seamless connection to connect with near and dear one. Dealing handover is always a challenging topic for wireless technologies. Mobile WiMAX introduces the most significant new feature, mobility to support handovers. Handover delay originates during data transmission but it should be less than a threshold time duration according to WiMAX forum standard for real time applications. This chapter includes WiMAX technology, its architecture, handover schemes and improvements in mobility for handover schemes with QualNet Network Simulator.

Wireless Sensor Network

Wireless Sensor Network (WSN) has an enormous prospective in hazardous areas such as underground coal mines. However, there is a need to ensure safety while installing WSN in underground coal mine as it is hazardous in nature and WSN radiates Radio Frequency (RF) signals which can be an eminent source of ignition. Henceforth when the underground coal mines are equipped with WSN there is a need to set the threshold limits of different physical parameters in order to eradicate such hazards for enabling safety. Therefore, in the present chapter, attempts have been made to assess the required safety for WSN while installing in underground coal mines. In addition, various types of hazards associated with underground coal mines and their consequences are elaborated in details with a glimpse to mitigate them with the use of WSN.

Vampire Attacks in Wireless Ad-hoc Networks

The advancements made in the field of wireless networks have led the technology to the use of wireless ad-hoc networks in mainstream routines. The performance of these networks is heavily depends on routing protocols. Various routing protocols have been proposed. However, these protocols are prone to various type of attacks. This chapter discusses the vampire attack that is a risk to the energy resources of the wireless ad-hoc networks which drain the energy of the network by sending protocol compliant messages. In this chapter, we identify various categories of vampire attacks. This chapter discusses a secure sensor routing protocol designed to be invulnerable to various attacks but its topology discovery phase is vulnerable to the vampire attacks. This chapter also presents a modification to the protocol's topology discovery phase to detect the nodes performing vampire attacks and prevent the network from these attacks.

Target Tracking in Wireless Sensor Network

Wireless Sensor nodes are being employed in various applications like in traffic control, battlefield, and habitat monitoring, emergency rescue, aerospace systems, healthcare systems and in intruder tracking recently. Tracking techniques differ in almost every application of Wireless Sensor Network (WSN), as WSN is itself application specific. The chapter aims to present the current state of art of the tracking techniques. It throws light on how mathematically target tracking is perceived and then explains tracking schemes and routing techniques based on tracking techniques. An insight of how to code localization techniques in matlab simulation tool is provided and analyzed. It further draws the attention of the readers to types of tracking scenarios. Some of the well established tracking techniques are also surveyed for the reader's benefit. The chapter presents with open research challenges that need to be addressed along with target tracking in wireless sensor networks.

Throughput and Compatibility Analysis of TCP Variants in Heterogeneous Environment

When TCP Reno and TCP Vegas connections share a link, TCP Reno generally steals more bandwidth and dominates TCP Vegas because of its aggressive nature. This is the major reason why TCP Vegas has not gained much popularity and deployment in the Internet despite its excellent standalone performance. This work systematically examines compatibility between Reno and Vegas in wired as well as in wireless networks. Popular Active Queue Management (AQM) technique named as Random Early Detection (RED) to minimize the incompatibility between Reno and Vegas in wired network. For wireless network two ad hoc routing protocols such as Ad Hoc On-Demand Distance Vector (AODV) and Destination-Sequenced Distance Vector (DSDV) are considered. Simulation results show that the incompatibility between Reno and Vegas in wired network is minimized using popular RED techniques. But in wireless ad hoc network environment Reno's aggressive behavior gets deteriorated while sharing with Vegas. Moreover, Reno and Vegas are more compatible in wireless network than wired network when both coexist in same time.

Diameter-Aggregation Delay Tradeoff for Data Gathering Trees in Wireless Sensor Networks

We define the aggregation delay as the minimum number of time slots it takes for the data to be aggregated in a Data Gathering tree (DG tree) spanning all the nodes of the sensor network; the diameter of a DG tree is the maximum distance (number of hops) from a leaf node to the root node of the tree. We assume that intermediate nodes at the same level or different levels of a DG tree could simultaneously aggregate data from their respective child nodes using different CDMA (Code Division Multiple Access) codes; but, an intermediate node has to schedule non-overlapping time slots (one for each of its child nodes) to aggregate data from its own child nodes. We employ an algorithm to determine the minimum aggregation delay at every intermediate node of the Bottleneck Node Weight (BNW) and Bottleneck Link Weight (BLW)-based DG trees. We observe the BNW-DG trees to incur a smaller tree diameter, but a significantly larger aggregation delay; on the other hand, the BLW-DG trees incur a larger tree diameter and a relatively lower aggregation delay, especially with increase in node density.

Sensor Localization in Three-Dimensional Space

Thanks to key advances in wireless communication and electronics, sensors have emerged as an appealing technology for several interesting applications, such as civilian (health and environment monitoring), natural (disaster detection), military (battlefield surveillance), and agricultural (precision agriculture) applications, to name a few. When grouped together, these sensors form a network to measure and gather data of the surrounding environment with respect to a specific phenomenon. The sensors are battery-powered, tiny devices that possess all the characteristics of a traditional computer, including storage, processing, and communication capabilities. In addition, these sensors are capable of sensing the environment and collecting data regarding several parameters, such as temperature, light, sound, vibration, etc. Unfortunately, all the sensors' capabilities are limited due to their physical size. In particular, the sensors have limited battery power as usually they are equipped with AA/AAA batteries whose lifetime is short. Therefore, the main challenge in the design of this type of network is the sensors' battery power (or energy), which is a critical component for the operation of the whole network. Moreover, these sensors communicate (possibly) wirelessly with each other to collect sensed data and accomplish the goals of their missions. To this end, the sensors are required to know their locations and those of their neighbors. Therefore, sensor localization is a crucial aspect for the design and development of wireless sensor networks. Various algorithms and protocols have been developed for sensor localization in both two-dimensional and three- dimensional wireless sensor networks. However, the problem of sensor localization in a three-dimensional space has not been investigated in the literature as extensively as its counterpart in a two-dimensional space. In this book chapter, we propose to study the sensor localization problem in three-dimensional wireless sensor networks. More precisely, this book chapter's sole focus will be on three-dimensional sensor deployment, and it aims to provide an overview of the existing solutions to the localization problem in a three-dimensional space. Basically, it proposes a classification of localization algorithms, and discusses different three-dimensional sensor localization approaches along with their motivation and evaluation.