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行動計算與網路簡介 Introduction to Mobile Computing and Networking

行動計算與網路簡介 Introduction to Mobile Computing and Networking. 王國禎 國立交通大學 資訊科學系 行動計算與寬頻網路實驗室 http://pds.cis.nctu.edu.tw Email: kwang@cis.nctu.edu.tw. 大綱. 行動計算與網路發展背景 無線通信本質 電腦的行動性 無線網路技術 行動式電腦技術 研究主題 結論. 行動計算與網路發展背景. 無線數位通信技術快速發展 通信及行動電腦成本降低 行動計算應用由業者推廣至一般消費者 目標：無遠弗屆. 無線通信的本質.

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行動計算與網路簡介 Introduction to Mobile Computing and Networking

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  1. 行動計算與網路簡介Introduction to Mobile Computing and Networking 王國禎 國立交通大學 資訊科學系 行動計算與寬頻網路實驗室 http://pds.cis.nctu.edu.tw Email: kwang@cis.nctu.edu.tw

  2. 大綱 • 行動計算與網路發展背景 • 無線通信本質 • 電腦的行動性 • 無線網路技術 • 行動式電腦技術 • 研究主題 • 結論

  3. 行動計算與網路發展背景 • 無線數位通信技術快速發展 • 通信及行動電腦成本降低 • 行動計算應用由業者推廣至一般消費者 • 目標：無遠弗屆

  4. 無線通信的本質 • 頻寬窄及變動大 • 高位元錯誤率 (BER) • 電池蓄電的限制

  5. 電腦的行動性 • 新研究課題：對網路、作業系統及資訊 系統的影響 • 網路及通信主題 • 位置管理：位置不固定 (Mobile IP) • 應用軟體：位置相關性 (Location-dependent applications) • 主從架構 (on-demand) 與出版式架構 (publishing)

  6. 無線與有線環境的最大差異 • 單一頻寬為所有使用者共享 • 無干擾的情況下，同頻道 (channels) 可以再用 • cells → microcells → picocells

  7. Hierarchical Cell Structure (HCS)

  8. 無線網路技術 • Analog cellular systems • Digital cellular systems • Cordless telephony • Wireless LANs • Private wireless data networks and metropolitan area wireless networks • Satellite networks • Future PCS (IMT-2000)

  9. IMT-2000 的目標 • Expanded range of services • A unified, seamless infrastructure • Integration of mobile and fixed networks • Bridge the telecommunication gap • Broadband transport • Self-adaptive, reprogrammable terminals • Virtual home environment

  10. IMT-2000 的系統規格 • Hierarchical cell structure • Globe roaming • Terminal mobility • Personal mobility • Service provider portability (via software radio) • Expanding radio spectrum

  11. Major Difference between cdma2000 and WCDMA (1) • Duplex and multiple access scheme • cdma2000: Frequency Division Duplex Multi-Carrier CDMA (FDD MC-CDMA) • WCDMA: Frequency Division Duplex Direct-Sequence CDMA (FDD DS-CDMA) • Chip rate • cdma2000: 3.6864Mcps • WCDMA: 3.84Mcps

  12. Major Difference between cdma2000 and WCDMA (2) • Forward link pilot for channel estimation • cdma2000: CDM common pilot channel • WCDMA: Common pilot channel or TDM dedicated pilot channel • Antenna beam forming and spot beams • cdma2000: Auxiliary pilot channel • WCDMA: TDM dedicated pilot channel

  13. Major Difference between cdma2000 and WCDMA (3) • Base station synchronization • cdma2000: Synchronous • WCDMA: Asynchronous • Base station acquisition and detection • cdma2000: Synchronization through time shifted PN correlation • WCDMA: 3 step parallel code search for base station detection and slot/frame • Network Signaling Support • cdma2000: IS-41,GSM-MAP • WCDMA: GSM-MAP

  14. Next generation network service portability

  15. Frequency allocation

  16. GPRS • GPRS is an extension of existing GSM bearer services • Enlarge the data rate from 9.6 kb/s to 170 kb/s • Uses packet-switch instead of circuit -switch • GPRS is well suited to replace SMS, or may be as an SMS bearer

  17. 第三代行動電話 • 寬頻高速傳輸 • 顯示即時新聞 • 傳遞數位影像 • 連接網際網路 • 瀏覽首頁 • 收發電子郵件 • 執行電子商務

  18. 第三代行動網路應用

  19. 即時影像與電子商務

  20. 行動式電腦技術 • 電池壽命增長：doze mode • 儲存技術：flash memory v.s. disks • 使用者介面：pen-based • 顯示技術：small-size

  21. 高能源效率軟體之設計 • CPU scheduling for low power • New communication protocols • Energy-aware application designs

  22. 研究主題 • Mobile networking (DL, NL, TL) • Information services(mobile wireless clients  information resources on the fixed networks) • Power management(at the software level as well as at the hardware level) • System issues in mobile computing(key issues: the issues of disconnection) • affects file system and database design • Research prototypes

  23. 行動計算之主要研究挑戰 • Mobility (registration vs. searching) • Variable communication conditions • fading • noise • interference • Energy limitations

  24. 行動計算與行動通信 • Mobile communications involve • Physical layer: IR, radio • MAC layer: CSMA/CA, FDMA, TDMA, CDMA, W-CDMA • Mobile computing involves • Mobile networking (DL, NL, TL) • Software applications (AL)

  25. IEEE 802.11 vs. HomeRF

  26. Bluetooth • Major joint computing and telecomm industry initiative • Plan to deliver a revolutionary radio-based solution • Cable replacement, no line of sight restrictions • Prefect for mobile devices - small, low power, low cost • Open specification(license free)

  27. 應用層設計主題 • Application layer • WAP (Wireless Application Protocol) • I-mode (NTT DoCoMo) • Context-sensitive applications • Ubiquitous multimedia mobile computing

  28. PDS Entertainment Subscription Services PDS • Scroll through the menu of the phone: Services, Bookmarks, PDS. • Select PDS. You can change the language if you wish. • Give your PDS codes. • First you will see the available subscription services menu: Movie, Train, Airplane, Hotel, Restaurant. • For example: Select Hotel • Select the location of the hotel. • Select the hotel you are interesting. • Select the kind of room you want and the check in day. • Send. • You will receive a confirmation message.

  29. I-mode • 由 NTT DoCoMo 在99年2月推出之服務 • 封閉的 PDC 系統: 技術比 GSM 所提出的WAP 還要優越 • 提供一千兩百多個網站, 內容可分為: • 生活資訊: 新聞、氣象 • 金融服務: 轉帳、查詢 • 定票服務: 機票、火車票、餐廳訂位 • 線上訂貨: 超市、百貨 • 與美軍合作, 開發軍用 JINI 無線網際網路語言

  30. 結論 • Ubiquitous (seamless) multimedia mobile computing and networking • Providing right information at any time, any place, any terminal • Context-sensitive applications • Wearable computing • Personal web • Global village

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