COMP362 Wireless Sensor Networks What is a Sensor Node by acm31250

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									                                             What is a Sensor Node?
                                        • Sensor is a tiny electronic devices
           COMP362                        with four major components
    Wireless Sensor Networks                                                          1+1=2
                                                            Sensing      Processing
                                           25 degree



                                                         Communication     Power




                                    1                                                         2
                                                                                               2




     What is a Sensor Node?                            What is a WSN?
• Different kinds of sensor nodes




                                    3                                                         4
           What is a WSN?                 Sensor network history




                 Data




                              Query
                                                  Sensor networks on the battlefield

                                      5                                                        6




                Outline                               Great Duck Island

• Applications of WSN
• System overview
  – Sensing component
  – Communication component
• Key issues
                                                                         • 32 Mica2 motes
• Summary                                                                • temperature, barometer,
                                                                           humidity, etc.
                                                                         • 15 mins interval
                                                                         • two tiers
                                      7                                                        8
                                                                                                8
Habitat/environment monitoring                                               Scientific observation & forecasting

                                                                              • Hudson river ecosystem
 • Agriculture
    – King Family Farms, Intel Research, AgCanada, spring 2003
 • Testing water
    – Los Angeles County Sanitation District, UCLA, UC Merced, Loyola
      Marymount University, winter 2004
 • Fighting fire
    – Claremont Canyon, California , UCB, summer 2004
 • Seismology
    – San Gabriel Mountains, California, UCLA Department of Earth and
      Space Sciences, Center for Embedded Networked Sensing, spring
      2004
 • Volcano, glacial, …
                                                                        9                                                          10




Scientific observation & forecasting                                         Structural monitoring

 • Hudson river ecosystem




                                                                              Golden gate bridge monitoring, UCB, Culler, et al.
                                                                        11                                                         12
        Biomedical Sensors                Healthcare

                                           • CodeBlue, Harvard, 2004
  • Sensors help to create vision
                                              – Vital sign sensors <-> user carriers
                                              – Robustness, prioritization, security, tracking, etc.




                                    13                                                                 14
                                     13




Sensor network, the future                 Sensor network, the future




                                    15                                                                 16
  Sensor network, the future                                                     Outline
                                                                 • Applications of WSN
                                                                 • System overview
                                                                   – Sensing component
                                                                   – Communication component
                                                                 • Key issues
                                                                 • Summary



                                                           17                                  18




               System overview                                             System overview
                                      4MHz 8 bit Atmel
Radio (<100 kbps)
                                       micro-processor


                                               Sensors:
                                                 temperature
                                                 light
                                                 humidity …
                                               Memory:
                                                512 KB

             2 AA batteries, 2.5 Ah

                                                           19                                  20
                                                            19
    Sensor Board                      Sensor Board




Multiple Sensors Per Board
                             21                            22




Mica Weather Board                Ultrasonic Transceiver




                             23                            24
                  Acoustic Sensing                       Communication Component
                                                       • Communication chip and antenna


                                   Three Cars

                                                                         and
      Initial
    Calibration
   No Detection




                Detection when
               Energy Crosses
                                                  25                                      26
              Standard Deviation




   Communication Component                               Communication Component
• ZigBee is a published specification set of
  high level communication protocols for:
  – Low data rate, low power, low cost wireless
    systems operating in unlicensed RF domain

• Based on IEEE 802.15.4




                                                  27                                      28
      Communication Component                                                                                 Outline
                       ZigBee™          Bluetooth™         Wi-Fi™         GPRS/GSM
                       802.15.4          802.15.1          802.11b      1XRTT/CDMA            • Applications of WSN
                     Monitoring &                         Web, Video,
Application Focus      Control
                                      Cable Replacement
                                                            Email
                                                                        WAN, Voice/Data       • System overview
System Resource       4KB-32KB            250KB+            1MB+           16MB+
                                                                                                – Sensing component
Battery Life(days)    100-1000+             1-7              .1-5            1-7
                                                                                                – Communication component
Nodes Per
Network
                       255/65K+              7                30            1,000
                                                                                              • Key issues
Bandwidth (kbps)        20-250              720            11,000+          64-128
                                                                                              • Summary
Range(meters)            1-75+             1-10+            1-100           1,000+
                       Reliable,
                                          Cost,             Speed,
Key Attributes        Low Power,                                        Reach, Quality
                                       Convenience        Flexibility
                     Cost Effective

                                                                                         29                                     30




                              Key Issues                                                        Wireless Link characteristics
•   Wireless link characteristics                                                             • Wireless broadcast nature
•   Localization
•   Coverage
•   Topology control
•   Routing
•   Power management


                                                                                         31                                     32
  Wireless Link characteristics                  Wireless Link characteristics
• Signal interference/packet collisions        • Signal interference/packet collisions




                                          33                                             34




  Wireless Link characteristics                  Wireless Link characteristics
• Multiple Access Control (MAC)                • Multiple Access Control (MAC)
  – CSMA                                         – CSMA
                                                 – TDMA




                                          35                                             36
  Wireless Link characteristics                           Wireless Link characteristics
• Multiple Access Control (MAC)                         • Multiple Access Control (MAC)
  – CSMA                                                  – CSMA
  – TDMA                                                  – TDMA
                                                          – Hybrid




                                                   37                                               38




  Wireless Link characteristics                           Wireless Link characteristics
• Radio irregularity in physical environments           • Radio irregularity in physical environments
                                    Irregular Range       – Propagation attenuation
                                             of A            • Media
                                                             • Multipath
                                                          – Noise
                                                             • Thermal
                                    Asymmetric links         • Atmosphere absorption



 B, C, and D are of the same distance from A.
  Note that this pattern changes over time.        39                                               40
Localization                    Localization


           Where is the tank?
                                y         x



                                      z

                          41                   42




Localization                        Coverage




                          43                   44
                 Topology Control                                         Routing
                                                     • Single hop communication
                      Peer-to-Peer                  Destination



Star




       Cluster Tree
                                                                                                   Source
                                               45                                                   46




                      Routing                                     Power Management
• Multihop communication
                                                     • Increase the lifetime of the system while
       Destination                                     meeting functional requirements

                                                     • Energy consumptions
                                                         –   CPU
                                                         –   Wireless communication
                                                         –   Sensor
                                      Source             –   …
                                     Base Station
                                               47                                                   48
   Power Management                                        Projects of HKUST: Field
                                                             study at a coal mine



1-bit transmission power is about equivalent to the
           execution of 700 instructions




                                                      49                              50




           Ready to go                                     14 kilometer dark tunnel




                                                      51                              52
   Hey…             Mining Machines




               53                     54




Working face         Working face




               55                     56
Working face        Working face




               57                  58




Working face        Working face




               59                  60
Working face        Working face




               61                  62




Working face        Working face




               63                  64
                    Working face                          Working face




                                          65                                                             66




                   Coal Mine Monitoring
                                               REP Performance (location estimations)



   Energy
  Efficiency


                                                                            Seed 1 (25, 85)




                                                                                               Seed 3
                                                                                              (80, 50)


Location Sensing
 ID Assignment        WSN Prototype                                              Seed 2 (40, 10)




                                          67                                                             68
H. H. Harbor           Where is money




               69                          70




                     Ships need to wait…




               71                          72
                71
   Waiting Time Determines Profit        Ships: Waiting; Digging; Detecting




                                    73                                     74




           What we need?                                    Iso-Map

                                         • Challenges
• A Real Time                              – What should sensors report?
  Contour Map
• Traditionally:
  Sending Ships
• 100+ reasons to
  use sensor
  networks…
• Can each sensor
  sends data back?
                                    75                                     76
                               Iso-Map Design                                     Iso-Map Design

• Isoline node measurement                                           • Contour map generation
  – <Value, Location, Gradient>
  – Linear regression for gradient measurement

                              30


                              20
            Error (degrees)




                              10

                               0


                              -10
                                         p0
                              -20


                              -30
                                 3   4     5        6   7   8
                                          Node Degree

                                                                77                                         78




                              Network Model                               Sea Depth Measurement
• Restricted Floating Sensors (RFS)                                  • The Sonar Systems are Expensive!!




    The RFS model combines the features of
    both static and mobile sensor networks.




                                                                79                                         80
                Outline                           Summary
• Applications of WSN              • WSN are a widely applicable technology
• System overview
  – Sensing component
  – Communication component
• Key issues
• Summary



                              81                                              82




               Summary                            Summary
• Wireless communication           • Provide a bridge between the real physical
                                     and virtual worlds



                                                      WSN
• Self-organized networks




                              83                                              84
                   Summary                                             Acknowledgement
21 impressive technologies                                  • Zheng Yang, Ph.D. student at HKUST, helped
                                                              us significantly in putting together this note.
                                                            • Some materials are based on notes from the
10 emerging techniques                                        following people
                                                               – Jack Stankovic, University of Virginia
                                                               – Bhaskar Krishnamachari, USC
                                                               – Chenyang Lu, WUSTL
Sensor networks & M2M
Multi-channel video (Telco TV, Internet TV, DirecTV)
RFID technology
                                                       85                                                       86

								
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