Wireless 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 Xue
• 11-30-2005

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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 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
• 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, 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
• 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 2ltnlt4) 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 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.
• 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
  (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 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
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
• Sinks broadcast the interest
• Sensor nodes broadcast the advertisements
• Attribute-based namingThe 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
  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
• 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 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
• 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 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

• 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