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International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
OPPORTUNITIES AND TECHNICAL DEVELOPMENT
IN
WIRELESS SENSOR NETWORKS
Ms. K. VIJAYALAKSHMI , Assistant Professor
Department Of Computer Applications
Ethiraj College For Women
Egmore, Chennai – 600 008 , Tamilnadu, India.
Email id : lkviji@gmail.com
Abstract
Wireless Sensor Networks (WSN). These are small embedded sensing platforms with computing
and communication capabilities, which combine low cost, flexible and fast deployment, resilient
self management and embedded intelligence for cooperatively delivered value added
services.WSNis nothing but combining sensors, radios, and CPU’s into an effective wireless
sensor network requires a detailed understanding of the both capabilities and limitations of each
of the underlying hardware components, as well as a detailed understanding of modern
networking technologies and distributed systems theory.
Keywords
Wireless sensor networks; sensors; environmental factors; intelligent sensors; monitoring;
intelligent networks; technology; development; mobiles as sensors.
1. Introduction
Sensor networks are composed of a large number of sensingdevices, which are equipped
with limited computing and radiocommunication capabilities, a wireless sensor node (or simply
sensor node) consists of sensing, computing, communication, actuation, and power components.
Thesecomponents are integrated on a single or multiple boards, and packaged ina few cubic
inches.Due to advances in wireless communications and electronics over the last few years, the
development of networks of low-cost, low-power, multifunctional sensors has received
increasing attention. These sensors are small in size and able to sense, process data, and
communicate with each other, typically over an RF (radio frequency) channel. Wireless Sensor
Networks are new type of networked systems characterized by severely constrained
computational and energy resources. These networks will consist of hundreds or thousands of
self-organizing, low power, low cost wireless nodes. Sensor networks often have one or more
points of centralized control called base stations. A base station (sink) is typically a gateway to
another network, a powerful data processing or storage center, or an access point for human
interface which are used as a nexus to disseminate control information into the network or
extract data from it. They have enough battery power to surpass the lifetime of all sensor nodes,
sufficient memory to store cryptographic keys, stronger processors, and means for
communicating with outside networks. The sensor nodes establish a routing forest, with a base
station at the root of every tree. Base stations are many orders of magnitude more powerful than
sensor nodes.Real world sensing is undergoing a revolution. Advances in computing platform
miniaturization, low-power radio and autonomic networking have enabled networked sensor
systems that are more easily deployed and cost effective than ever before.
ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
2. Applications
The applications for WSNs are many and varied. They are used in commercial and industrial
applications to monitor data that would be difficult or expensive to monitor using wired sensors.
Figure 1: WSN Application Areas
Some of the typical applications are:
Environmental monitoring
Habitat monitoring
Acoustic detection
Seismic Detection
Military surveillance
Inventory tracking
Medical monitoring
Process Monitoring
Figure 2 : Wireless Sensor Network Module
A WSN system is ideal for an application like environmental monitoring in which the
requirements mandate a long-term deployed solution to acquire water, soil, or climate
measurements. For utilities such as the electricity grid, streetlights, and water municipals,
ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
wireless sensors offer a lower-cost method for collecting system health data to reduce energy
usage and better manage resources. In structural health monitoring, you can use wireless sensors
to effectively monitor highways, bridges, and tunnels. You also can deploy these systems to
continually monitor office buildings, hospitals, airports, factories, power plants, or production
facilities.
Figure 3 : Environmental, ground water, cathodicprotection, dams, docks, depots, stations,
areas, trucks, valves, humidity & temperature etc.
A Wireless Sensor Network is a self-configuringnetwork of small sensor nodes communicating
among themselves using radio signals, anddeployed in quantity to sense, monitor andunderstand
the physical world.Wireless Sensor nodes are called motes. WSN provide a bridge between the
real physicaland virtual worlds.Allow the ability to observe the previouslyunobservable at a fine
resolution over large spatiotemporalscales.Have a wide range of potential applications
toindustry, science, transportation, civil infrastructure,and security.
2.1. WSN application examples
1.Disaster relief operations
Drop sensor nodes from an aircraft over a wildfire
Each node measures temperature
Derive a “temperature map”
ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
2. Biodiversity mapping
Use sensor nodes to observe wildlife
3. Intelligent buildings (or bridges)
Reduce energy wastage by proper humidity, ventilation, air conditioning (HVAC) control
Needs measurements about room occupancy, temperature, air flow, …
Monitor mechanical stress after earthquakes
4. Machine surveillance and preventive maintenance
Embed sensing/control functions into places no cable has gone before
E.g., tire pressure monitoring.
5. Precision agriculture
Bring out fertilizer/pesticides/irrigation only where needed
6. Medicine and health care
Post-operative or intensive care
Long-term surveillance of chronically ill patients or theelderly
3. WSN System Architecture
In a common WSN architecture, the measurement nodes are deployed to acquire measurements
such as temperature, voltage, or even dissolved oxygen. The nodes are part of a wireless network
administered by the gateway, which governs network aspects such as client authentication and
data security. The gateway collects the measurement data from each node and sends it over a
wired connection, typically Ethernet, to a host controller.
ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
Figure 5: Common Wireless Sensor Network Architecture
4. Technology Development
WSNs form a particular class of ad hoc networks that operatewith little or no infrastructure.
WSNs are gaining momentumas they have great potential for both research and commercial
applications. The sensor network nodes themselves are ideallyof application specific sensors, a
wireless transceiver, asimple general purpose processor, possibly assisted by limited amount of
special-purpose hardware, and an energy unit thatmay be a battery or a mechanism to obtain
energy from theenvironment. We cannot assume that sensor nodes will be tamper- resistant,
although we will consider the availability of suchtamper-resistant nodes for future applications.
Sensor nodesare distributed over a potentially vast geographical area toform a static, multi-hop,
self-organizing network. However,also mobile WSNs and mobility within WSN are conceivable
Figure 6: Wireless Sensor Network architecture - Mote: a particle of dust”,
ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
4.1. Technology building blocks
WSNs are self-organizing networks of small embedded devices called motes4 as shown in
Figure 6. These are deployed in the environment being monitored, either placed individually or
scattered with high enough density relative to their sensing and communication ranges to ensure
good connectivity and sensing coverage.
The self-organization algorithms and protocols in the motes ensure that the devices form a
network and carry out their monitoring tasks. These include sensing activities, but may also
involve determining their location, exchanging sensing information, aggregating data, reasoning
in a local or distributed manner, raising alarms, activating other sensors, etc. As the devices are
generally constrained in terms of communication bandwidth, processing power and energy
supply, optimal use of the resources is an important factor in designing the monitoring tasks. In
order to communicate with the outside world, WSNs rely on gateways. These may be fixed or
mobile, permanently or intermittently present, unique or multiple. They allow access to the
monitoring services from a corporate network or the wider Internet. As a higher capability and
availability platform, the gateway can also host management, processing and security functions
for the WSN.
Figure 7 : Sensor node architecture
4.2. How Wireless Sensor Networks Work
Wireless Sensor Network mechanism is quite simple and applicable to a variety of fields. It is
based on Smaller nodes, controller, radio transceiver, and battery. The key to stimulate the sensor
networking is the algorithm sponsor multi-router phenomenon. The system is totally dependent
on the nodes and the harmony established between them through proper frequency. These nodes
are of different sizes according to the function they perform. To activate the monitoring /
tracking function of these nodes a radio transmitter is attached to forward the information in the
form of waves. They are controlled by the microcontroller according to the function and device
in which they are used. All the system remains in working condition with the help of energy
supply which is in the form of battery. The wireless sensor networks perform function
concurrently where nodes are autonomous bodies incorporated in the field spatially for the
accurate results. The information transmits through proper channel taking the information
collecting it in the form of data and send to the base.
ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
4.3. The Electromagnetic Spectrum
The Electromagnetic Spectrum can be used to fabricate Remote Sensors of a wide variety of
types. Generally the wavelength suitable for a particular application is selected based on the
propagation distance, the level of detail and resolution required, the ability to penetrate solid
materials or certain mediums, and the signal processing difficulty. Doppler techniques allow the
measurement of velocities. Millimeter waves have been used for satellite remote monitoring.
Infrared is used for night vision and sensing heat. IR motion detectors are inexpensive and
reliable. Electromagnetic waves can be used to determine distance using time-of-flight
information- Radar uses RF waves and Lidar uses light (laser). The velocity of light is c=
6
299.8x10 m/s. GPS uses RF for absolute position localization. Visible light imaging using
cameras is used in a broad range of applications but generally requires the use of sophisticated
and computationally expensive DSP techniques including edge detection, thresholding,
segmentation, pattern recognition, motion analysis, etc.
5. Advantages & Development of Wireless Sensors
5.1. Advantages :
Much cheaper to deploy than wired sensors
Sensor nodes can be added or removed easily
Node location can be changed without rewiring
Can be configured into different network topologies
- Star, Mesh, etc.
5.2. Development :
Figure 9: mobiles as sensors – a forecast
ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
International Conference on Computing and Control Engineering (ICCCE 2012), 12 & 13 April, 2012
6. Conclusion
This Paper presents an overview of the opportunities and technical development in Wireless
Sensor Networks. This paper describes briefly howall of this sensor network research is
producing a new technology. The future should see an accelerated pace of adoption of this
technology.It’s an interesting, complex, new technologyand lots of research still to be done.The
paper concludes on a note of quoting the inevitable role played by Wireless Sensor Networks and
its applications.
7. References
1. Wireless Sensor Networks: An Information Processing Approach (The Morgan
Kaufmann Series in Networking)Leonidas Guibas.
2. Fundamentals of Wireless Sensor Networks: Theory and Practice (Wireless
Communications and Mobile Computing)by Waltenegus Dargie.
3. Wireless Sensor Networks by Ian F. Akyildiz, Mehmet Can Vuran.
4. Agrawal, Dharma P.; Qing-An Zeng. 2003. Introduction to Wireless and Mobile
Systems. Brooks/Cole – Thompson, Pacific Grove, CA.
5. Wireless sensor networks: a networking perspective by Jun Zheng (Ph. D.), Jun
Zheng, Abbas Jamalipour.
6. Guide to Wireless Sensor Networks by Sudip Misra, Subhas Chandra Misra, Isaac.
7. Wireless Sensor Networks: Technology, Protocols, and Applications Kazem Sohraby,
Daniel Minoli, Taieb Znati.
8. Kazem Sohraby, Daniel Minoli, Taieb Znati., “Wireless Sensor Networks:
Technology,Protocols, and Applications”, Wiley Student Edition
9. Feng Zhao & Leonidas Guibas, “Wireless Sensor Networks, An Information
ProcessingApproach”, Morgan Kaufmann
10. Jun Zheng, Abbas Jamalipour, “Wireless Sensor Networks: A Networking
Perspective”,Wiley
11. Ian F. Akyildiz, Mehmet Can Vuran, “Wireless Sensor Networks”, Wiley
12. Waltenegus Dargie, Christian Poellabauer, “Fundamentals of Wireless Sensor
Networks:Theory and Practice”, Wiley
ISBN 978-1-4675-2248-9 © 2012 Published by Coimbatore Institute of Information Technology
