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Transcript

  • 1. Chapter 0: Overview Wireless Network Architecture & Potential Research Directions
      • Yu-Chee Tseng
      • Dept of Computer Science
      • National Chiao-Tung University
  • 2.  
  • 3. Wireless Network Models
    • With Infrastructure:
    • Without Infrastructure (ad hoc networks):
  • 4.
    • Cellular:
    • Infrared:
  • 5.
    • As relaying link
    • Packet Radio Network
  • 6. 無線隨意網路 ( Multi-hop Ad Hoc Network )
  • 7. 感測網路( Sensor Network )
  • 8. Nokia Rooftop Product
  • 9.  
  • 10.  
  • 11. Bluetooth Technology bluetooth headset bluetooth dongle bluetooth MP3 watch bluetooth remote car control
  • 12. Research Directions: Mobile Computing, Communications, and MEMS Technologies
  • 13. Three Directions Together
    • Wireless Communication Technology
    • Portable Computer Technology
      • appearance of light-weight computing devices
    • MEMS Technology
      • 微機電系統 (Micro Electro Mechanical Systems , MEMS) ,其定義為一個智慧型微小化的系統,包含感測、處理或致動的功能,包含兩個或多個電子、機械、光學、化學、生物、磁學或其他性質整合到一個單一或多晶片上。其應用領域極為廣泛,包括製造業、自動化、資訊與通訊、航太工業、交通運輸、土木營建、環境保護、農林漁牧等。
    • Vision: Ubiquitous/ Nomadic Computing, communication, and control
      • computers everywhere;
      • information anywhere anytime
      • control
  • 14. Features of Wireless Communication
    • one global bandwidth shared by all users
      • fortunately channels, such as (frequency, time-slot) pairs, can be reused
    • Radio-based
      • low bandwidth
      • high latency radio communication links
      • higher bit error rate (BER)
    • fading
      • short-term multipath fading (Rayleigh effect)
        • due to same signal taking different paths and arriving at the receiver shifted in phase
      • long-term fading (radio shadow)
        • topology of the terrain (like mountains) can cause signal dropouts
  • 15. Features of Portable Computers
    • Limited resources:
      • limited energy (battery life)
      • limited CPU speed
      • limited memory
      • limited display
    • Mobile Applications/Services
      • Pico-service: local parking lot availability, layout of a building
      • Micro-service: train and bus station information
      • Macro-service: weather information, news service, stock market information
    • Real-time multimedia applications
      • tele-medicine
      • collaborative working environment
  • 16. Features of MEMS
    • MEMS (Micro Electro Mechanical Systems) are the integration of electrical devices and mechanical structures at the micrometer (10 -6 m = 0.000001 m) scale.
      • The essence of MEMS is their ability to perform and enhance tasks, in ways and in the micro world , impossible using conventional technologies.
    digital propulsion Microthruster optical switch segway
  • 17. Research: Hardware Aspects
    • power saving
      • display, LCD
      • low-voltage CPUs
        • Example: AT&T's Hobbit chip: 5,000 times less power consumption in doze mode than active mode
      • radio: an example of IEEE 802.11 power consumption
        • transmit: 1400 mW
        • receive: 1000 mW
        • idle: 830 mW
        • sleep: 130 mW
      • “ transmitting 1 bit is equal to executing > 1000 instructions
  • 18. Research: Software Aspects
    • mobile communication protocols
      • WAP
      • wireless TCP
      • Mobile IP
      • MAC protocols
    • Energy-efficient protocol
      • related to the above send/receive/idle/sleep model
    • Mobile Operating Systems:
      • Windows Mobile, Android, etc.
  • 19. Research: Application Aspects
    • Compute, communicate, and micro-control
    • Context-aware computing
      • context includes
        • user's location
        • environment (e.g., noise level, communication b/w, communication cost etc.)
        • social situation (e.g., with boss, with co-worker etc.)
      • context-aware applications
        • context-sensitive information access (e.g. where are the bookstores in the vicinity)
        • context-sensitive commands : in active badge system
          • command format: <badge> <location> <event-type> <action>
          • Ex: Coffee Kitchen arriving “play -v 50 ~/sound/rooster.au”

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