1 / 34

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.

fuller
Download Presentation

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

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related