sensor networks a survey
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Wireless Sensor Networks: A Survey
I. F. Akyildiz, W. Su, Y. Sankarasubramaniam and E. Cayirci
Presented by Yuyan Xue11-30-2005
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Outline
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.
Random deployment Cooperative capabilities
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Introduction
Sensor networks VS ad hoc networks: 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 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 enviro
nment 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
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
Fault Tolerance Scalability Hardware Constrains Sensor Network Topology Environment Transmission Media Power Consumption
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Factors influencing sensor network design
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.
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Factors influencing sensor network design
Scalability
Scalability measures the density of the sensor nodes.
Density = (R) =(N R2)/AR – Radio Transmission Range
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Factors influencing sensor network design
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.
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Factors influencing sensor network design
Hardware constraints
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Factors influencing sensor network design
Sensor network topology Pre-deployment and deployment phase Post-deployment phase Re-deployment of additional nodes
phase
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Factors influencing sensor network design
Environment 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 In a multihop sensor network, communicati
ng 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
Sensing Communication Data processing
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Communication architecture of sensor
networks
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Communication architecture of sensor networks
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: 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 Propagation Effects
Minimum output power (dn 2=<n<4) Ground reflect – Multihop in dense sensor net work
Power Efficiency Modulation SchemeM-ary Modulation schemeUltra wideband(impulse radio)
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Communication architecture of sensor networks
Open research issues Modulation schemes Strategies to overcome signal propag
ation 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.
Medium Access Control Power Saving Modes of Operation Error Control
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Communication architecture of sensor networks
Medium access control
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 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 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 Error control modes in Communication Networks (addi
tional 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 self-organization
Error control coding schemes. Power saving modes of operation
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Communication architecture of sensor networks
Network layer: 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
•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
Energy Efficient Routes
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Communication architecture of sensor networks
Interest Dissemination
Sinks broadcast the interest Sensor nodes broadcast the advertisements 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
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 New protocols need to be developed to address hi
gher topology changes and higher scalability. New internetworking schemes should be develope
d to allow easy communication between the sensor networks and external networks.
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Communication architecture of sensor networks
Transport layer: 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 Because acknowledgments are too costl
y, 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: 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) 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
MIT d'Arbeloff Lab – The ring sensor
Monitors the physiological status of the wearer and transmits the information to the medical professional over the Internet
Oak Ridge National Laboratory Nose-on-a-chip is a MEMS-based se
nsor It can detect 400 species of gases a
nd transmit a signal indicating the level to a central control station
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iButton
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 Memory Button Java Powered Cryptographic iButton Thermochron iButton
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iButton Applications
Caregivers Assistance Do not need to keep a bunch of keys. Only one
iButton will do the work Elder Assistance
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 Investigate behavior of
children/patient Features:
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
Applications of sensor networks Factors influencing sensor network
design Communication architecture of
sensor networks
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