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					An Introduction of Wireless Sensor
         Networks (WSN)
           Technology



        Zhan Yi (Student ID:80423272)

                 Kuroda Lab.
      Department of Electrical Engineering
               Keio University
                                Outline
Introduction
What is WSN?
Why we need it?


WSN structure
How WSN is organized?
What are the specialties of WSN?


The achievement some research units have made
UCB (David Culler)
Intel
UCB (Kris Pister )
MIT Media Lab. (Joe Paradiso)

Some fields interesting
    WSN Introduction (What is WSN?)
Habitat Monitoring on the Great Duck Island (USA Maine. 2002/2003.
UCB & Intel & Atlantic Univ.)




                              (1)                    (2)
                                               (3)
                  (4)                 (5)
         Communication Topology
                                 Sensor node
                                                      Multi-hop
                                                      wireless

Internet or           Sink /
Satellite             Base
                      Station                             area A


                        Cluster-Head
                        or Aggregator
Task
Manager
Node
                                               Self-organizing,
                 Density of nodes
End User                                       non-homogenous
                   (R) = N R2/A
                                               sensor network
              N is number of nodes in area A
              R is radio range
         Introduction (Why we need it?)

Seamless and Ubiquitous Communication with the real world.


Wide Usages
  Military applications
  Environmental applications
  Health applications
  Home applications
  Traffic Surveillance
  Other commercial applications …
                                Outline
Introduction
What is WSN?
Why we need it?


WSN structure
How WSN is organized?
What are the specialties of WSN?


The achievement some research units have made
UCB (David Culler)
Intel
UCB (Kris Pister )
MIT Media Lab. (Joe Paradiso)

Some fields interesting
 WSN Structure (How WSN is organized?)

Sensor node (For example, Mote
made by UCB)

  Mote – node used for low-power, wireless,
  sensor networks’ terminal.

  Multi-channels transceiver with extended
  range.

  Support TinyOS- special operating system
  developed for WSN.

  Support for wireless remote
  reprogramming.

  sensor boards and data acquisition add-
  on boards.
  WSN Structure (How WSN is organized?)
 Sensor node



Sink /
Base
Station          What is behind it?
                 Why it can work?




                                                                                                               Task management plane
                                                                                   Mobility management plane
                                      Application Layer




                                                          Power management plane
   Multi-hop                          Transport Layer
   wireless
                                      Network Layer

                                      Data-link Layer

                                      Physical Layer
WSN Structure (How WSN is organized?)
Power management plane:
Manage a sensor node how to use its energy.    know itself


Mobility management plane:
Detects and registers the movement of sensor nodes, know its neighbors and
balance their power and task usage.  know others around


Task management plane:
Balances and schedules the sensing tasks given to a specific region.
  know whole sensor nodes in the network
WSN Structure (How WSN is organized?)
Physical Layer: responsible for frequency selection, modulation
and data encryption.


Data-link Layer: responsible for multiplexing of data streams,
data frame detection, Medium Access control (MAC) and error
control.


Network Layer:    route the data supplied by the Transport layer,
special multi-hop wireless routing protocols between sensor
nodes and sink nodes.


Transport Layer: maintain the flow of data if the Application
Layer requires it. Needed if End-User accesses the Sensor
Network through the Internet.


Application Layer: Makes the hardware and software of the lower
layers transparent to the End-User.
WSN Structure (What are the specialties of WSN?)
 WSN’s special characters
    Person unattended, inaccessible.
   Limited resource - power, memory, MPU…
   Topology changes/breaks frequently (war field, etc).
    High density employed, broadcast communication paradigm (normal ad-hoc
   networks uses point-to-point communications).


 WSN’s research characteristics
    Self-organization.
    Scientific topology, routing and low power..
    Fault tolerance & robustness.
    Security



    Must be self-organized, self-maintaining and operate at low
  duty cycle.
                                Outline
Introduction
What is WSN?
Why we need it?


WSN structure
How WSN is organized?
What are the specialties of WSN?


The achievement some research units have made.
UCB (David Culler)
Intel
UCB (Kris Pister )
MIT Media Lab. (Joe Paradiso)

Some fields interesting
Achievement some research units have made
Prof. David Culler (UC. Berkeley)
   Mote (Sensor node)
                        Mote Platform Evolution
Achievement some research units have made
 Tiny OS -- An operating system for tiny devices embedded in
 physical world
  a: support self-configure sensor networks.
  b: small open source, energy efficient, software OS developed by UC Berkeley.
  c: provides services to simplify writing programs (standard C) that capture and
  process sensor data and transmit message over the radio.
  d: open source community: www.tinyos.net.

 Present work
  a: efficient routing.
  b: maintain and update for the Tiny OS (version 2.0 now).
  c: application based on WSN, like habitat monitoring, structure monitoring,
  microclimate monitoring…
   Achievement some research units have made

Intel www.intel.com/research/exploratory/heterogeneous.htm
     Heterogeneous sensor networks:
     Solve problem of how to improve fault
     tolerance and energy consumption when
     the nodes grows and using multi-hoc
     broadcasting way.

     a: theory was verified effective.                       Ad-hoc sensor network with a high bandwidth 802.11
     b: lessen data transmission.                            mesh overlay network based on Intel Xscale Technology

     c: efficient routing.



     Intel mote:
     a: bases on the prototype by Berkeley mote
     (support TinyOS).
     b: now is focusing on ultra low power, function
     level integration, hardware configuration.

                                                                         Path across overlay networks
Achievement some research units have made
Prof. Kristofer Pister (UC. Berkeley)
   Smart Dust (sensor node)
   a: very small size (millimeter-scale, MEMS).
   b: micromachined CCR, solar cell array, accelerator & photoactive sensor, ADC,
   microcontroller.
   c: “Ultra-low energy microcontroller” is reported in ISSCC 2004.
Achievement some research units have made
  Smart Dust is used in company (Dust INC. – Smart Mesh)
  a: building automation
  b: industry monitoring
  c: security and protection services


  Present work
  a: Berkeley Webs – use WSN developed technology serve for the school.
  b: routing security.
  c: synthetic insect – smart dust with legs.
Achievement some research units have made.
Prof. Joe Paradiso (MIT. Media Lab)
   Electronic sensate skin   (http://web.media.mit.edu/~lifton/Tribble)




a: 33cm diameter sphere with 22 patches which sports vibration-sensitive,
   local pressure, light, sound, temperature sensors.
b: neighbor-to-neighbor wired communication, no centre controller.
c: RJ22 cable connects all the patches (15.2kb/s), each patch has
   microprocessor (8bit/22MIPS).
Achievement some research units have made.

  Wireless wearable system for Gait
  evaluation
  (http://www.media.mit.edu/resenv/GaitShoe/index.html)



  a: an on-shoe device that can be used
  for continuous and real-time gait
  monitoring.

  b: send data wirelessly, providing
  information about the three-
  dimensional motion, position, and
  pressure distribution of the foot.

  c: real-time data collecting for physical
  therapy.
               Some fields interesting


Efficient routing
Low power
Security
Programming the Ensemble (configuration)
THANK YOU !

				
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posted:3/29/2009
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