3. Introduction
3
A sensor network is composed of a large number
of sensor nodes, which are densely deployed
either inside the phenomenon or very close to it.
Random deployment
Cooperative capabilities
4. Applications of sensor networks
4
Temperature
Humidity
Vehicular movement
Lightning condition
Pressure
Soil makeup
Noise levels
The presence or absence of certain kinds of objects
Mechanical stress levels on attached objects
The current characteristics such as speed, direction, and
size of an object
6. Applications of sensor networks
6
Military applications
Monitoring friendly forces, equipment and
ammunition
Battlefield surveillance
Reconnaissance of opposing forces and terrain
Battle damage assessment
Nuclear, biological and chemical attack detection
and reconnaissance
7. Applications of sensor networks
7
Environmental applications
Forest fire detection
Flood detection
Precision agriculture
8. Applications of sensor networks
8
Health applications
Tele monitoring of human physiological data
Tracking and monitoring patients and doctors inside
a hospital
Drug administration in hospitals
Home applications
Home automation
Samrt environment
9. Factors influencing sensor network design
9
Fault tolerance
Fault tolerance is the ability to sustain sensor
network functionalities without any interruption
due to sensor node failures.
The fault tolerance level depends on the
application of the sensor networks
Scalability
Scalability measures the density of the sensor
nodes.
10. Factors influencing sensor network design
10
Production costs
The cost of a single node is very important to
justify the overall cost of the networks.
The cost of a sensor node is a very challenging
issue given the amount of functionalities with a
price of much less than a dollar.
13. Factors influencing sensor network design
13
Transmission media
In a sensor network, communicating nodes are
linked by a wireless medium. To enable global
operation, the chosen transmission medium
must be available worldwide.
Radio
infrared
optical media
17. Communication architecture of sensor networks
17
Application layer
The three possible application layer protocols are -
Sensor management protocol (SMP)
Task assignment and data advertisement protocol
(TADAP)
Sensor query and data dissemination protocol
(SQDDP)
18. Communication architecture of sensor networks
18
Transport layer
This layer is especially needed when the system is
planned to be accessed through Internet or other
external networks.
No attempt thus far to propose a scheme or to
discuss the issues related to the transport layer of a
sensor network in literature.
19. Communication architecture of sensor networks
19
Network layer
Power efficiency is always an important
consideration.
Data aggregation is useful only when it does not
hinder the collaborative effort of the sensor nodes.
An ideal sensor network has attribute-based
addressing and location awareness.
21. Communication architecture of sensor networks
21
Data link layer
The data link layer is responsible for the medium
access and error control. It ensures reliable point-to-
point and point-to-multipoint connections in a
communication network.
Medium access control
Creation of the network infrastructure
Fairly and efficiently share communication resources
between sensor nodes
22. Communication architecture of sensor networks
22
Power saving modes of operation
Operation in a power saving mode is energy efficient
only if the time spent in that mode is greater than a
certain threshold.
Error control
Forward Error Correction (FEC)
Automatic Repeat Request (ARR)
Simple error control codes with low-complexity
encoding and decoding might present the best
solutions for sensor networks.
23. Communication architecture of sensor networks
23
Physical layer
The physical layer is responsible for frequency selection,
frequency generation, signal detection, modulation and
data encryption.
CONCULSION
Flexibility and fault tolerance create exciting new
applications for remote sensing
In future the wide range of applications will make sensor
networks an integral part of our lives
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