wsn unit 1

1. OVERVIEW OF WIRELESS
SENSOR NETWORKS:
 Key definitions of sensor networks.
 Advantages of sensor Networks.
 Unique constraints an challenges.
 Driving Applications.
 Enabling Technologies for Wireless
Sensor Networks.

2. Key Definitions of Sensor
Networks:
•Sensor
•Sensor node
•Network topology
•Routing
•Date-centric
•Geographic routing
•Geographic routing
•Collaborative processing
•In-network

3.  Uncertainty
 State
 Task
 Detection
 Classification
 Value of information or
information utility.
 Resource
 Sensor tasking

4.  Embedded operating system
(OS)
 Evaluation metric
 Node services
 Data storage

5. Advantages of Sensor Networks:
 Energy Advantage:
Psend ∝ rα Preceive

6.  Detection Advantage
 SNRr =
10 log Psource − 10 log Pnoise − 20
log r.
 Increasing the sensor density by a factor of k
reduces the average distance to a target by a
factor of .
 Increase in sensor density by a factor of k improves
the SNR at a sensor by 10 log k db.

7. Applications of wireless
sensor networks:
Military applications
 Monitoring inimical forces
 Monitoring friendly forces and
equipment
 Military-theater or battlefield
surveillance
 Targeting
 Battle damage assessment
 Nuclear, biological, and chemical
attack detection and more ...

8. Environmental applications
 Microclimates
 Forest fire detection
 Flood detection
 Precision agriculture and more ...
Health applications
 Remote monitoring of physiological
data
 Tracking and monitoring doctors and
patients inside a hospital
 Drug administration
 Elderly assistance and more ...

9. Home applications
 Home automation
 Instrumented environment
 Automated meter reading and more ...
Commercial applications
 Environmental control in industrial and
office buildings
 Inventory control
 Vehicle tracking and detection
 Traffic flow surveillance and more ...
Disaster relief applications
Precision agriculture

10. Enabling Technologies for
Wireless Sensor Networks:
 Hardware:
 Wireless Networking:
 Collaborative Signal Processing:
 Energy scavenging:

11. Challenges for WSNs
1.Characteristic requirements
2.Required mechanisms
1.Characteristic requirements:
 Type of service
 Quality of Service
 Fault tolerance
 Lifetime
 Scalability
 Wide range of densities
 Programmability
 Maintainability

12. 2. Required mechanisms
 Multihop wireless communication
 Energy-efficient operation
 Auto-configuration
 Collaboration and in-network
processing.
 Data centric
 Locality
 Exploit trade-offs

13. ARCHITECTURES:
Single-Node Architecture –
 Hardware Components
 Energy Consumption of Sensor Nodes
 Operating Systems and Execution
Environments,
Network Architecture –
 Sensor Network Scenarios
 Optimization Goals and Figures of
Merit
 Gateway Concepts.

14. Hardware Components
 Controller.
 Memory
 Sencor and actuqtors.
 Communication.
 Power supply.

15. Overview of main sensor node
hardware components

16. Transceiver operational states

17. Energy Consumption of
Sensor Nodes
 1. Operation states with
different power consumption.
 2. Microcontroller energy
consumption.
 3. Memory.
 4. Radio transceivers.

18. Operation states with different
power consumption:

19.  Eoverhead = tup(Pactive + Psleep)/2.
 Esaved =(tevent − t1)Pactive −
(τdown(Pactive + Psleep)/2 +
(tevent − t1 − τdown)Psleep).
 Eactive = Pactive(tevent − t1) .

20. Operating Systems and
Execution Environments:
 1. Embedded operating systems:
 2. Programming paradigms:
Concurrent Programming
(sequential prog model).
Process-based prog model
Event-based programming model

22. Network Architecture –
 Sensor Network Scenarios:
1.Types of sources and sinks.
2.Single-hop versus multihop
networks.
3.Multiple sinks and sources.
4. Three types of mobility.

23.  Source-a source is an entity in the
network that can provide information
 Sink- It is the entity where information
is required
 1.Neighbour node
 2.Hand held device (PDA)
 3.INTERNET

24. 2.Single-hop versus multihop networks.

25. 3.Multiple sinks and sources

26. 4. Three types of mobility.
 Node mobility.
 Sink mobility.
 Event mobility.

27. Optimization Goals and
Figures of Merit:
 1.Quality of service.
 2. Energy efficiency.
 3. Scalability.
 4. Robustness .(QoS +scalability )

28. Quality of service
LOW LEVEL ATTRIBUTES
 DATA TRANSMISSION
 DETECTION OF EVENT
 MODULATION TECHNIQUES
 CHANNEL

29. HIGH LEVEL QOS
ATTRIBUTES
 EVENT DETECTION/REPORTING
PROBABILITY
 EVENT CLASSIFICATION-ERRORS
 EVENT DETECTION DELAY
 MISSING REPORTS
 TRACKING ACCURACY

30. Energy efficiency.
 Energy per correctly received bits
 Energy per reported event
 Delay/energy trade off
 Network life time
Payload –the energy required to
transfer I bit of information

31. DESIGN PRINCIPLES FOR
WSN
 Distributed organization
 In network processing
 Adaptive fideility and accuracy
 Data centricity (address data, not
nodes)

32. Gateway Concepts:
 The need for gateways

33.  WSN to Internet communication

34.  Internet to WSN communication

35.  WSN tunneling:(Gateways can also
act as simple extensions of one
WSN to another WSN. )