Transcript Wireless sensor networks: a survey

Wireless Sensor Networks:
A Survey
I. F. Akyildiz, W. Su, Y.
Sankarasubramaniam and E. Cayirci
Presented by Yuyan Xue
11-30-2005
Outline
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Introduction
Applications of sensor networks
Factors influencing sensor network
design
Communication architecture of sensor
networks
Conclusion
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Introduction
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.
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Random deployment
Cooperative capabilities
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Introduction
Sensor networks VS ad hoc networks:
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The number of nodes in a sensor network can be several
orders of magnitude higher than the nodes in an ad hoc
network.
Sensor nodes are densely deployed.
Sensor nodes are limited in power, computational
capacities and memory.
Sensor nodes are prone to failures.
The topology of a sensor network changes frequently.
Sensor nodes mainly use broadcast, most ad hoc networks
are based on p2p.
Sensor nodes may not have global ID.
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Applications of
Sensor networks
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Applications of sensor networks
Military applications
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Monitoring friendly forces, equipment and
ammunition
Reconnaissance of opposing forces and
terrain
Battlefield surveillance
Battle damage assessment
Nuclear, biological and chemical attack
detection
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Applications of sensor networks
Environmental applications
 Forest fire detection
 Biocomplexity mapping of the
environment
 Flood detection
 Precision agriculture
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Applications of sensor networks
Health applications
 Tele-monitoring of human physiological
data
 Tracking and monitoring patients and
doctors inside a hospital
 Drug administration in hospitals
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Applications of sensor networks
Home and other commercial applications
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Home automation and Smart environment
Interactive museums
Managing inventory control
Vehicle tracking and detection
Detecting and monitoring car thefts
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Factors Influencing
Sensor Network Design
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Factors influencing sensor
network design
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Factors influencing sensor
network design
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Fault Tolerance
Scalability
Hardware Constrains
Sensor Network Topology
Environment
Transmission Media
Power Consumption
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Factors influencing sensor
network design
Fault tolerance
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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.
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Factors influencing sensor
network design
Scalability
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Scalability measures the density of the
sensor nodes.
Density =  (R) =(N  R2)/A
R – Radio Transmission Range
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Factors influencing sensor
network design
Production costs
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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.
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Factors influencing sensor
network design
Hardware constraints
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Factors influencing sensor
network design
Sensor network topology
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Pre-deployment and deployment phase
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Post-deployment phase
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Re-deployment of additional nodes phase
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Factors influencing sensor
network design
Environment
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Busy intersections
Interior of a large machinery
Bottom of an ocean
Surface of an ocean during a tornado
Biologically or chemically contaminated field
Battlefield beyond the enemy lines
Home or a large building
Large warehouse
Animals
Fast moving vehicles
Drain or river moving with current.
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Factors influencing sensor
network design
Transmission media
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In a multihop 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
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Factors influencing sensor
network design
Power Consumption
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Sensing
Communication
Data processing
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Communication architecture
of sensor networks
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Communication architecture of
sensor networks
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Combine power and
routing awareness
Integrates date with
networking protocols
Communicates power
efficiently through the
wireless medium
Promotes cooperative
efforts among sensor
nodes.
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Communication architecture of
sensor networks
Physical layer:
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Address the needs of simple but robust
modulation, transmission, and receiving
techniques.
frequency selection
carrier frequency generation
signal detection and propagation
signal modulation and data encryption.
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Communication architecture of
sensor networks
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Propagation Effects
Minimum output power
(dn 2=<n<4)
Ground reflect – Multihop in dense
sensor net work
Power Efficiency Modulation Scheme
M-ary Modulation scheme
Ultra wideband(impulse radio)
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Communication architecture of
sensor networks
Open research issues
 Modulation schemes
 Strategies to overcome signal
propagation effects
 Hardware design: transceiver
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Communication architecture of
sensor networks
Data link layer:
The data link layer is responsible for the
multiplexing of data stream, data frame detection,
the medium access and error control.
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Medium Access Control
Power Saving Modes of Operation
Error Control
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Communication architecture of
sensor networks
Medium access control
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Creation of the network infrastructure
Fairly and efficiently share communication
resources between sensor nodes
Existing MAC protocols (Cellular System,
Bluetooth and mobile ad hoc network)
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Communication architecture of
sensor networks
MAC for Sensor Networks
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Self-organizing medium access control for sensor networks
and Eaves-drop-and-register Algorithm
CSMA-Based Medium Access
Hybrid TDMA/FDMA-Based
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Communication architecture of
sensor networks
Power Saving Modes of Operation
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Sensor nodes communicate using short data
packets
The shorter the packets, the more dominance
of startup energy
Operation in a power saving mode is energy
efficient only if the time spent in that mode is
greater than a certain threshold.
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Communication architecture of
sensor networks
Error Control
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Error control modes in Communication Networks
(additional retransmission energy cost)
Forward Error Correction (FEC)
Automatic repeat request (ARQ)
Simple error control codes with low-complexity encoding
and decoding might present the best solutions for sensor
networks.
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Communication architecture of
sensor networks
Open research issues
 MAC for mobile sensor networks
 Determination of lower bounds on the
energy required for sensor network selforganization
 Error control coding schemes.
 Power saving modes of operation
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Communication architecture of
sensor networks
Network layer:
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Power efficiency is always an important
consideration.
Sensor networks are mostly data centric.
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.
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Communication architecture of
sensor networks
Energy Efficient Routes
•Maximum available power (PA) route:
Route 2
•Minimum energy (ME) route: Route 1
•Minimum hop (MH) route: Route 3
•Maximum minimum PA node route:
Route 3
•Minimum longest edge route: Route 1
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Communication architecture of
sensor networks
Interest Dissemination
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Sinks broadcast the interest
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Sensor nodes broadcast the advertisements
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Attribute-based naming
“The areas where the temperature is over 70oF ”
“The temperature read by a certain node ”
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Communication architecture of
sensor networks
Data aggregation
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Solve implosion and overlap
Problem
Aggregation based on same
attribute of phenomenon
Specifics (the locations of
reporting sensor nodes) should
not be left out
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Communication architecture of
sensor networks
Several Network Layer Schemes for Sensor Networks
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Communication architecture of
sensor networks
Open research issues
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New protocols need to be developed to address
higher topology changes and higher scalability.
New internetworking schemes should be developed
to allow easy communication between the sensor
networks and external networks.
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Communication architecture of
sensor networks
Transport layer:
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This layer is especially needed when the system is
planned to be accessed through Internet or other
external networks.
TCP/UDP type protocols meet most requirements
(not based on global addressing).
Little attempt thus far to propose a scheme or to
discuss the issues related to the transport layer of
a sensor network in literature.
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Communication architecture of
sensor networks
Open research issues
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Because acknowledgments are too costly,
new schemes that split the end-to-end
communication probably at the sinks may
be needed.
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Communication architecture of
sensor networks
Application layer:
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Management protocol makes the hardware
and software of the lower layers transparent
to the sensor network management
applications.
Sensor management protocol (SMP)
Task assignment and data advertisement
protocol (TADAP)
Sensor query and data dissemination
protocol (SQDDP)
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Communication architecture of
sensor networks
Sensor management protocol (SMP)
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Introducing the rules related to data aggregation, attribute-based
naming, and clustering to the sensor nodes
Exchanging data related to the location
finding algorithms
Time synchronization of the sensor nodes
Moving sensor nodes
Turning sensor nodes on and off
Querying the sensor network configuration and the status of
nodes, and reconfiguring the sensor network
Authentication, key distribution, and security in data
communications
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Some Other Interesting
Applications
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MIT d'Arbeloff Lab – The ring
sensor
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Monitors the physiological status of
the wearer and transmits the
information to the medical
professional over the Internet
Oak Ridge National Laboratory
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Nose-on-a-chip is a MEMS-based
sensor
It can detect 400 species of gases
and transmit a signal indicating the
level to a central control station
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iButton
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A 16mm computer chip armored in a stainless
steel can
Up-to-date information can travel with a
person or object
Types of i-Button
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Memory Button
Java Powered Cryptographic iButton
Thermochron iButton
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iButton Applications
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Caregivers Assistance
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Do not need to keep a bunch of keys. Only one
iButton will do the work
Elder Assistance
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They do not need to enter all their personal
information again and again. Only one touch of
iButton is sufficient
They can enter their ATM card information and
PIN with iButton
Vending Machine Operation Assistance
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iBadge - UCLA
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Investigate behavior of children/patient
Features:
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Speech recording / replaying
Position detection
Direction detection / estimation(compass)
Weather data: Temperature, Humidity,
Pressure, Light
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iBadge - UCLA
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Conclusion
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Applications of sensor networks
Factors influencing sensor network
design
Communication architecture of sensor
networks
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