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Wireless Sensor Network
Vibhor Saraswat
Final Yr –ECE
Guide- Miss Rashmi Sharma
Poornima
College of Engineering
www.powerpointpresentationon.blogspot.c
CONTENTS
• INTODUCTION OF WIRELESS
• WIRELESS SENSOR NETWORK
• SENSOR NODE
• NETWORK TOPOLOGIES
• NETWORK APPLICATION
• CONCLUSION
Why Talk About Wireless?
• Wireless communication is not a new technology but
•
•
•
cell phones have brought revolution in wireless
communication
Wireless Technology has changed the way
o Organizations & individuals work & live today
In less than 10 years
o World has moved from fixed to wireless networks
o Allowing people, mobile devices & computers talk to
each other, connect without a cable
o Only available option for field data acquisition
Interconnectivity with multiple devices
o Using radio-waves, sometimes light
Ubiquitous Computing
• Future State of Computing Technology?
o Mobile, many computers
o Small Processors
o Low Power Consumption
o Relatively Low Cost
Growth in Wireless Systems
•Rapid growth in cellular voice services
oCell phones everywhere!
•Several wireless technology options have
been available for the last ~10-20 yrs
oMini cell stations using existing standards like
CDMA or GSM
oWireless PABX using PCS standards such as
DECT.
oSatellite and microwave backhaul
Wireless Sensor Networks (WSN)
Sensor
s
Deplo
y
What is a WSN?
Sensor: The
device
•
Observer: The end
user/computer
Phenomenon: The entity of interest to the
observer
A network that is formed when a set of small sensor
devices that are deployed in an “ad hoc fashion” no
predefined routes, cooperate for sensing a physical
phenomenon.
• A Wireless Sensor Network (WSN) consists of base
stations and a number of wireless sensors.
• It simple, tiny, inexpensive, and battery-powered
Why Wireless Sensors Now?
• Moore’s Law is making sufficient CPU performance
available with low power requirements in a small size.
• Research in Materials Science has resulted in novel
sensing materials for many Chemical, Biological, and
Physical sensing tasks.
• Transceivers for wireless devices are becoming
smaller, less expensive, and less power hungry (low
power tiny Radio Chips).
• Power source improvements in batteries, as well as
passive power sources such as solar or vibration
Typical Sensor Node Features
•A sensor node has:
oSensing Material
 Physical – Magnetic, Light, Sound
 Chemical – CO, Chemical Weapons
 Biological – Bacteria, Viruses, Proteins
oIntegrated Circuitry (VLSI)
 A-to-D converter from sensor to circuitry
oPackaging for environmental safety
oPower Supply
 Passive – Solar, Vibration
Sensor Network
Server
Sensor field
Communications
barrier
Gateway
Internet
Sensor Network
Server
Watershed
Sensor
field
Gateway
Internet
Sensor Node Hardware
Sensor + Actuator + ADC + Microprocessor + Powering
Unit
+ Communication Unit (RF Transceiver) + GPS
•Portable and self-sustained (power, communication,
intelligence).
•Capable of embedded complex data processing.
Sensors and Wireless Radio
• Types of sensors:
-Pressure,
-Temperature
-Light
-Biological
-Chemical
-Strain, fatigue
• Capable to survive harsh
environments (heat, humidity,
corrosion, pollution etc).
• No source of interference to
systems being monitored
and/or surrounding systems.
Advances in Wireless Sensor
Nodes
Consider Multiple Generations of Berkeley Motes
Model
CPU
Flash
Memory
SRAM
Radio
Rene 2 Rene 2
Mica
Mica 2
4 MHz
8 MHz
4 MHz 4 MHz
8 KB
16 KB
128 KB 128 KB
32 KB
32 KB
512 KB 512 KB
10 Kbps 10 Kbps 40 Kbps 40 Kbps
Network characteristics of WSN
•Generally, the network:
oConsists of a large number of sensors
(103 to 106 Hz)
oSpread over large geographical region
(radius = 1 to 103 km)
oSpaced out in 1, 2, or 3 dimensions
oIs self-organizing
oUses wireless media
Sensor Network Topology
• Hundreds of nodes require careful handling of topology
maintenance.
• Predeployment and deployment phase
o Numerous ways to deploy the sensors (mass, individual
placement, dropping from plane..)
• Postdeployment phase
o Factors are sensor nodes position change, reachability
due to jamming, noise, obstacles etc, available energy,
malfunctioning, theft, sabotage
• Redeployment of additional nodes phase
o Redeployment because of malfunctioning of units
Network Topologies
• Star
o Single Hop Network
o All nodes
communicate
directly with
Gateway
o No router nodes
o Cannot self-heal
o Range 30-100m
o Consumes lowest
Network Topologies
• Mesh
o Multi-hopping network
o All nodes are routers
o Self-configuring network
o Node fails, network self-heals
o Re-routes data through
shortest path
o Highly fault tolerant network
o Multi-hopping provides much
longer range
o Higher power
consumption…nodes must
always listen!
Network Topologies
• Star-Mesh Hybrid
o Combines of star’s low
power and…
o …mesh’s self-healing and
longer range
o All endpoint sensor nodes
can communicate with
multiple routers
o Improves fault tolerance
o Increases network
communication range
o High degree of flexibility
and mobility
WSN APPLICATIONS
• Potential for new intelligent applications:
o Smart Homes
o Process monitoring and control
o Security/Surveillance
o Environmental Monitoring
o Construction
o Medical/Healthcare
• Implemented with Wireless Sensor Networks!
Medical and Healthcare Appln
Remote
Databases
Backbone
Network
Net
Switch
In
Hospital
Physician
Net
Switch
Wireless Remote
consultation
Possibility for Remote consulting
(including Audio Visual
communication)
Application in Environment
Monitoring
• Measuring pollutant
concentration
Pollutants monitored by sensors
in the river
• Pass on information
to monitoring station
• Predict current
ST
location of pollutant
volume based on
various parameters
• Take corrective
Sensors report to the base
monitoring station
Putting Sensor in
vehicle
•Vehicle equipped with sensor and sort range
wireless communication capability can form
ad-hoc vehicular wireless mesh network (V
MESH)
•Two application scenarios:
•Vehicular traffic monitoring and control.
•Inter connecting Patches of sensor network.
Power Consumption
•Limited Power Source
•Battery Lifetime is limited
•Each sensor node plays a dual role of data
originator and data router (data processor)
•The malfunctioning of a few nodes
consumes lot of energy (rerouting of
Environmental Factors
•Wireless sensors need to operate in
conditions that are not encountered by
typical computing devices:
oRain, sleet, snow, hail, etc.
oWide temperature variations
 May require separating sensor from
electronics
oHigh humidity
oSaline or other corrosive substances
CONCLUSION
•Security in WSN is quite different from
traditional (Wired) network security.
•We have proposed three network
topologies for WSN.
•Our schemes substantially improves
References
• Wireless & Mobile Systems Prof Dharma Prakash
Agrawal and H. Deng
• Integrating Wireless Technology in the Enterprise by
Williams Wheeler, Elsevier Digital Press
• www.google.com
• www.wikkipedia.com
Any
Questions?