sensors are what we experience the most in our life. they are even working in our body in different aspects. they may be as eyes, ears, skin, tongue etc. when we combine them they make a network. it may be a human sensor network. but i have shared something interesting about wireless sensor networks.
1. WIRELESS SENSOR NETWORKS
(WSN)
Muhammad Jawwad
12MDTLC0585
University of Engineering and Technology Peshawar
Telecommunication Department (Mardan Campus)
2. CONTENTS LAYOUT
• Introduction
• Sensor Node
• Some Design issues and Routing Challenges
• Routing Protocols in WSNs
• Applications of WSNs
• References
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3. WHAT IS A WIRELESS SENSOR
NETWORK??
• Highly distributed networks of small
light-weighted wireless nodes,
• Deployed in large numbers,
• With sensing, computation and
wireless communication capabilities.
• Monitors the environment or system
by measuring the physical
parameters such as temperature,
pressure etc.
• Figure[1]
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4. INTRODUCTION
• With the recent technological advancements, the
manufacturing of small and low cost sensors became
technically and economically feasible.
• The sensing electronics collects the information from the
surroundings and transforms into an electric signal.
• Processing these signal gives us the properties about the
object located near the sensor nodes.
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5. INTRODUCTION (CONTD.)
• A Wireless Sensor Network (WSN) consists
of hundreds or thousands of sensor
nodes.
• These sensors have the ability to
communicate either among themselves
or directly to an external base station
(BS).
• A greater number of sensors allows for
sensing over larger geographical regions
with greater accuracy.
• The architecture of a simple WSN is shown
in the figure[1].
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6. SENSOR NODES
• A general sensor node is made up of four basic components as
shown in figure.
A Sensing Unit.
Sensing units are usually composed of two subunit: sensors and
analog to digital converter (ADC). The analog signal sensed by the
sensors is converted to digital signals by ADC and then feeds into
processing unit.
A Processing Unit.
It is a small storage unit, that manages to collaborate the nodes with
other nodes to carry out the assigned task.
A Transceiver Unit.
A transceiver unit connects the node to the network.
A Power Unit.
One of the most important unit of a sensor is a power unit. It may be
supported by a power scavenging unit such as solar cells.figure[2]
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8. ROUTING CHALLENGES & DESIGN
ISSUES
• Despite of innumerable applications of WSNs, these networks
have some restrictions.
• The design of routing protocols in WSNs is influenced by many
challenging factors. These factors must be overcome before
efficient communication can be achieved in WSNs.
• In the following slide I have summarized some of the routing
challenges and design issues that effect routing process in
WSNs.
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9. ROUTING CHALLENGES & DESIGN
ISSUES
• Node Deployment.
Node deployment in WSNs is application dependent and effects the
performance of the routing protocol. The deployment can be of two types:
1. Deterministic Deployment.
In deterministic deployment, the sensors are manually placed and data is routed through
pre-defined paths.
2. Randomized Deployment.
In randomized deployment, the sensor nodes are scattered randomly creating an
infrastructure in an ad-hoc manner. In this technique optimal clustering becomes necessary
to allow connectivity and enable energy efficient network operations.
• Fault Tolerance.
Sensors may fail due to lack of power, physical damage or environmental
interference. This should not effect the sensor networks.
If sensor nodes fail, the routing protocol must be able to accommodate
formation of new links or routes to data collection base station.
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10. ROUTING CHALLENGES & DESIGN
ISSUES
• Energy Consumption (without loosing accuracy).
Most important point to be considered in this case is energy efficiency.
Sensor nodes can use up their limited energy supply over computation
and transmitting information in a wireless environment.
As such, energy conserving forms of communication and computation
are essential.
• And some of the others are;
Scalability
Network Dynamics
Data Aggregation
Quality of Service etc. etc.
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11. NOW HEADING TOWARDS
ROUTING PROTOCOLS IN WSNs[2]
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12. ROUTING PROTOCOLS IN WSN
• As I discussed there must be some specific set of rules, routing
techniques or to be specific routing protocols for sending data
between sensor nodes and base stations.
• Different routing protocols are defined for WSNs.
• These protocols can be classified according to different
parameters.
• P.T.O
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13. UNIVERSITY OF ENGINEERING AND TECHNOLOGY PESHAWAR (TELECOMMUNICATION ENGG.)
Classification of
Routing Protocols
Based on Mode of
Functioning and Type
of Target Applications
Proactive Reactive
Hybrid
According to the
Participation style of
the Nodes.
Direct Communication Flat
Clustering Protocols
Depending on the
Network Structure
Data Centric Hierarchical
Location Based
14. PROACTIVE PROTOCOLS:
• In a Proactive Protocol the nodes switch on their sensors and
transmitters,
• Sense the environment
• Transmit the data to a BS through the predefined route.
• These are also called table driven routing protocols.
• Examples: The Low Energy Adaptive Clustering hierarchy
protocol (LEACH) utilizes this type of protocol.
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15. • This type of protocol is used in Time Critical applications.
• The nodes react immediately to the sudden changes of the
environment,
• Beyond the predetermined threshold values.
• Examples: The Threshold sensitive Energy Efficient sensor
Network (TEEN) is an example of a reactive protocol.
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REACTIVE PROTOCOLS:
16. HYBRID PROTOCOLS:
• Hybrid protocols use a combination of both Proactive and
Reactive protocols.
• First the sensor nodes calculate the length of the routes and
then they choose the best (shortest) route.
• It is energy efficient.
• Adaptive Periodic TEEN(APTEEN) is an example of a reactive
protocol.
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17. UNIVERSITY OF ENGINEERING AND TECHNOLOGY PESHAWAR (TELECOMMUNICATION ENGG.)
Classification of
Routing Protocols
Based on Mode of
Functioning and Type
of Target Applications
Proactive Reactive
Hybrid
According to the
Participation style of
the Nodes.
Direct
Communication
Flat
Clustering Protocols
Depending on the
Network Structure
Data Centric Hierarchical
Location Based
18. DIRECT COMMUNICATION:
• In this type of protocols, any node can send information to the
Base Station(BS) directly.
• When applied to a very large network, the energy of sensor
nodes may be drained quickly.
• Its scalability is very small.
• SPIN is an example of this type of protocol.
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19. FLAT:
• In this protocol, if any node needs to transmit data, it first
searches for a valid route to the BS and then transmits the
data.
• Nodes around the base station may drain their energy quickly.
• Its scalability is average.
• Examples: Rumor Routing is an example of this type of
protocol.
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20. CLUSTERING PROTOCOLS:
• In this type of protocols,
network is divided into a
number of clusters having
sensors.
• Each cluster has its own cluster
head (CH).
• This a CH only communicates
with the BS directly.
• All the other sensors in the
cluster collect data and send
to CH.
• TEEN and LEACH is an example
of this type of protocol.
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21. UNIVERSITY OF ENGINEERING AND TECHNOLOGY PESHAWAR (TELECOMMUNICATION ENGG.)
Classification of
Routing Protocols
Based on Mode of
Functioning and Type
of Target Applications
Proactive Reactive
Hybrid
According to the
Participation style of
the Nodes.
Direct Communication Flat
Clustering Protocols
Depending on the
Network Structure
Data Centric Hierarchical
Location Based
22. DATA CENTRIC:
• These are query based protocols.
• It depends upon the naming of the desired data, it decreases
the redundancy.
• The BS sends queries to specific section of the network for
information.
• Depending on the query, sensor collects particular data of the
interest and sends back to BS.
• It also reduces the number of transmissions.
• SPIN was the first data centric protocol.
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23. HIERARCHICAL:
• It is energy efficient routing protocol.
• Nodes with higher energy are used to transmit data to the
base station.
• And nodes with low energy do the sensing and data
collection tasks.
• LEACH,TEEN and APTEEN are some examples.
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24. LOCATION BASED:
• In this type of protocols location information of sensor nodes is
required.
• Location information can be obtained from Global Positioning
System(GPS)signals.
• Using location information an optimal path can be formed.
• Geographic and Energy-Aware Routing(GEAR)protocol is
example of this.
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25. SOME OTHER PROTOCOLS ARE:
• Sensor Protocols for Information via Negotiation (SPIN).
• Directed Diffusion.
• Rumor Routing.
• Gradient-Based Routing.
• COUGAR.
• ACQUIRE.
• Energy Aware Routing etc.
• If you want to study them more deeply study [2].
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26. APPLICATIONS OF WSN
• Wireless sensor networks are now becoming the basic needs of
our technological World.
• It has already many applications in our daily life.
• Whether it is commercial use or domestic use, military use or
medical use.
• Some of them are listed in next slides.
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27. APPLICATIONS OF WSN
• Environmental Applications:
Forrest Fire Detection (Figure 1.1)[1].
Flood Detection.
Precision Agriculture.
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28. APPLICATIONS OF WSN
• Military Applications:
Monitoring opposing forces movement and ammunitions.
Battle field surveillance.
Nuclear, Biological and Chemical attack detection.
Shooter Localization [3].
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29. APPLICATIONS OF WSN
• Health Applications:
Monitoring of human
physiological data.
Such as ibadge.[4]
Investigate behavior of
children/patient
Features
o Speech recording / replaying
o Position detection
o Direction detection /
estimation(compass)
o Weather data: Temperature,
Humidity, Pressure, Light.
Tracking and monitoring patients
and doctors inside a hospital.
Drug administration in hospital.
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30. APPLICATIONS OF WSN
• Home and other Commercial Applications:
Home automation and smart environment.
Interactive museums.
Vehicle tracking and detection.
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31. REFERENCES
1. Google
2. Jamal N. Al-Karaki, Ahmed E. Kamal,” Routing Techniques in
Wireless Sensor Networks: A Survey”, Dept. of Electrical and
Computer Engineering Iowa State University, Ames, Iowa
50011 .
3. J. Sallai, J., A. Ledeczi, and P. Volgyesi, "Acoustic Shooter
Localization with a Minimal Number of Single-Channel
Wireless Sensor Nodes", SenSys 2011.
4. www.slideshare.com, “Wireless Sensor Networks:
A Survey”, Presented by Yuyan Xue, 11-30-2005.
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