無線網路與行動計算簡介 Introduction to Wireless Networks and Mobile Computing

1. 無線網路與行動計算簡介Introduction to Wireless Networks and Mobile Computing 王國禎 國立交通大學 資訊工程系 行動計算與寬頻網路實驗室 http://mbl.cs.nctu.edu.tw Email: kwang@cs.nctu.edu.tw

2. 大綱 • 無線網路與行動計算發展背景 • 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. 無線網路與行動計算發展背景 • 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：無遠弗屆及充滿智慧 (Ubiquitous and Intelligent) • Information seeks people

6. 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

7. 電腦的行動性 • 新研究課題：對網路、作業系統及資訊 (應用）系統的影響 • 網路及通信主題 • 位置管理：位置不固定 (Mobile IPv4, IPv6) • 應用軟體：文脈感測： 如位置相關性 (Context-sensitive applications, e.g., location-dependent applications) • 主從架構 (on-demand) ，出版式架構 (publishing) 與 同輩式（peer to peer)

8. 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 • Macrocells → microcells → picocells

9. Hierarchical Cell Structure (HCS)

10. 無線網路技術(1) • 1G: Analog cellular systems • 2G: Digital cellular systems • Cordless telephony • Wireless LANs: 802.11a/b/g/n • Private wireless data networks and metropolitan area wireless networks • Satellite networks • 3G: IMT-2000: WCDMA, cdma2000

11. 無線網路技術(2) • WiMax (802.16a/e for MAN) and MobileFi (802.20- for WAN – Pending) • ITU 4G: 100 Mbps (when moving) (2010 or earlier); 1 Gbps (when standstill)

12. 無線網路技術(3) • Principal 4G candidates: LTE (Long-Term Evolution, GSM oriented, 3GPP), UMB (Ultra Mobile Broadband, CDMA-oriented, 3GPP2), and IEEE 802.16m (also called WiMax II) • GSM (2.3 billion); CDMA (450 million) (Source: IEEE Computer, Nov. 2007)

13. 下一代無線網路評比

14. Wireless Technology Roadmap (Source: Dell) GSM GPRS EDGE WCDMA (UMTS) HSPDA 2 Mbps 115 kbps 384 kbps WWAN 1xEV-DV 1xEV-DO CDMA2000 1xRTT 3.1 Mbps 144 kbps 2.4 Mbps MobileFi 802.20 BWA 802.16e WiMAX 802.16a 2-60 Mbps 802.11g Wi-Fi 802.11b 802.11n WLAN 54 Mbps 11 Mbps 802.11a 100+ Mbps Bluetooth 1.1 Bluetooth 1.2 Bluetooth EDR Bluetooth 2.x 1 Mbps 3 Mbps WPAN Zigbee 802.15.4’ Zigbee 802.15.4 1 Mbps 250 Kbps NG UWB UWB 802.15.3a 100 Mbps+ 480 Mbps Past 2004 2005 2006 2007+ Wireless technologies, categorized by mobility and range, will continue to evolve to higher data rates... Increasing Range and Mobility 

15. Wireless Application Landscape: Wireless technologies, categorized by mobility and range, will continue to evolve to higher data rates... (Source: Dell) Text, Graphics, Internet, Compressed Audio Multi-channel Video & HDTV Data, Streaming Video, Internet, Hi-Fi Audio MAN 802.16e 802.16a Long Range WAN GSM/CDMA GPRS/3G MMDS/LMDS 802.11b/g LAN 802.11n 802.11g/a Short Range Bluetooth 2 (MR) UWB Zigbee PAN Bluetooth 1.1 Low Data Rate High Data Rate Very high Data Rate

16. 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 (software radio) • Virtual home environment (VHE)

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

18. Next generation heterogeneous network services

19. Frequency allocation

20. 2.5G: 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 • Evolution: GSM → GPRS → EDGE/ EGPRS (384Kbps, 470 Kbps)

21. 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 • MExE • 瀏覽首頁 • 收發電子郵件 • 執行電子商務

22. MExE • Mobile Station Application Execution Environment • Specified in the 3G UMTS to provide a standard execution environment for an MS to access Internet and Intranet services • A mechanism supporting VHE concept

24. 第三代行動網路應用

25. 即時影像與電子商務

26. 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 • Decoupling the user interface logic and communication logic from the processing logic of each application • 顯示技術：small-size, display independence

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

28. 研究主題 (1) • Mobile networking (DL, NL, TL) • Information services(mobile wireless clients  information resources on the fixed networks; peer-to-peer computing) • 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

29. 研究主題 (2) • Research prototypes • http://www.mobileinfo.com/Education/universities_MobileResearch.htm • http://www.intel.com/research/exploratory/ubiqcomp_research.htm • http://www.research.ibm.com/WearableComputing/ • http://mobileandpervasive.blogspot.com

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

31. 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, OFDM, OFDMA • Mobile computing involves • Mobile networking (DL, NL, TL) • Software applications (AL)

32. IEEE 802.11 vs. HomeRF

34. 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)

35. Bluetooth (cont.) • Basic use of Bluetooth: • Data/voice access point • Personal ad hoc network • Cable replacement

36. 應用層設計主題 • Application layer • WAP 2.0 (Wireless Application Protocol) • XHTML MP (mobile profile) • I-mode (NTT DoCoMo) • Context-sensitive applications • Ubiquitous intelligent mobile multimedia computing

37. 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. • Input your PDS customer ID and password. • 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 interested. • Select the kind of room you want and the check-in day. • Send. • You will receive a confirmation message.

38. I-mode • 由 NTT DoCoMo 在1999年2月推出之服務 • 由封閉的 PDC 系統 至 3G WCDMA • 加入JAVA, Jini, Java Card 技術 • Three-fold way: subscriber, service provider, content provider • 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

39. 結論 • Ubiquitous intelligent mobile multimedia computing and IP-based broadband wireless networking (3G, 4G (HSDPA, HSUPA), 802.11n, WiMax, WiMax II, NG UWB) • Ad hoc and sensor networks • Actively providing right information at any time, any place, any terminal (context-sensitive applications) • Peer to peer computing • Wearable computing • Personal web • Global village • Digital home (smart home care)

40. 結論 (cont.) • RFID tags are an example of the embedded intelligence delivered by ubiquitous wireless networks (EE Times) • A high level of computational intelligent distributed services through the network (EE Times) • Obstacles yet to overcome for ubiquitous intelligent wireless networking (EE Times) • Regulation • Consumer acceptance • Device scaling • Power consumption • Nanoscaling

41. 結論 (cont.)(Source: Dr. William C.Y. Lee) • Future 4G system is based on selection and integration • Future 4G system is aiming at the user-centric • The lifestyle will be changed due to the future communications

42. 結論 (cont.)(Source: Dr. William C.Y. Lee) • The future wireless • In the past – selecting a better system • In the future – achieving a defined goal from user’s aspect

43. 結論 (cont.)(Source: Dr. William C.Y. Lee) • The user’s perspective in the future • No need to be physically in any meeting due to digital conferencing technology • Anything can be found and located by RFID • Reducing crime by camera, GPS and E911 • Mobile office