PDPDSS

無線網路與行動計算簡介Introduction to Wireless Networks a

nd 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

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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

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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

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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

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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)

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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

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Hierarchical Cell Structure (HCS)

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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

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無線網路技術 (2)• WiMax (802.16a/e for MAN) and Mobil

eFi (802.20- for WAN – Pending)

• ITU 4G: 100 Mbps (when moving) (2010 or earlier); 1 Gbps (when standstill)

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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)

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下一代無線網路評比

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Wireless technologies, categorized by mobility and range, will continue to evolve to higher data rates...

Wireless Technology Roadmap (Source: Dell)WLAN

WLAN

Wi-Fi802.11b

Wi-Fi802.11b 802.11g802.11g

802.11a802.11a

802.11n802.11n 11 Mbps

100+ Mbps 54 Mbps

Incr

easi

ng

Ran

ge

and

Mo

bil

ity

WWAN

WWAN GSM

GPRSGSM

GPRS115 kbps

WCDMA(UMTS)

WCDMA(UMTS)

EDGEEDGE HSPDAHSPDA384 kbps 2 Mbps

CDMA2000

1xRTTCDMA2000

1xRTT 1xEV-DV1xEV-DV1xEV-DO1xEV-DO144 kbps 2.4 Mbps 3.1 Mbps

2007+2007+200620062005200520042004PastPast

WPAN

WPAN

Bluetooth1.1

Bluetooth1.1

Bluetooth1.2

Bluetooth1.2

BluetoothEDR

BluetoothEDR

Zigbee802.15.4Zigbee

802.15.4UWB

802.15.3aUWB

802.15.3a

Zigbee802.15.4’Zigbee

802.15.4’

3 Mbps

250 Kbps1 Mbps

100 Mbps+NG UWBNG UWB

480 Mbps

Bluetooth2.x

Bluetooth2.x 1 Mbps

BWA

BWA

WiMAX802.16aWiMAX

802.16a 802.16e802.16e

MobileFi802.20

MobileFi802.20

2-60 Mbps

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Shor

t R

ange

Lon

g R

ange

Low Data Rate High Data Rate Very high Data Rate

PAN

LAN

WAN

Text, Graphics,Internet, Compressed Audio

Data, Streaming Video,Internet, Hi-Fi Audio

Multi-channel Video & HDTV

Wireless Application Landscape: Wireless technologies, categorized by mobility and range, will continue to evolve to higher data rates... (Source: Dell)

UWB

MMDS/LMDS

802.11b/g

802.11g/a

GSM/CDMAGPRS/3G

Bluetooth 1.1

ZigbeeBluetooth 2 (MR)

802.11n

802.16eMAN

802.16a

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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)

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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

Next generation heterogeneous network services

Frequency allocation

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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)

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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

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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

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第三代行動網路應用

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即時影像與電子商務

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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

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高能源效率軟體之設計

• CPU scheduling for low power

• New communication protocols

• Energy-aware application designs

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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

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研究主題 (2)• Research prototypes– http://www.mobileinfo.com/Education/u

niversities_MobileResearch.htm– http://www.intel.com/research/explorato

ry/ubiqcomp_research.htm– http://www.research.ibm.com/Wearable

Computing/– http://mobileandpervasive.blogspot.com

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行動計算之主要研究挑戰• Mobility (registration vs. searching)

• Variable communication conditions– fading– noise– interference

• Energy limitations

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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)

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IEEE 802.11 vs. HomeRF

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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)

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

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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

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•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.

PDS Entertainment Subscription Services

PDS

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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 provid

er, 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

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結論• Ubiquitous intelligent mobile multimedia computing a

nd 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)

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結論 (cont.)• RFID tags are an example of the embedded intelli

gence 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

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結論 (cont.) (Source: Dr. William C.Y. Le

e)

• 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

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結論 (cont.) (Source: Dr. William C.Y. Le

e)

• The future wireless– In the past – selecting a better system– In the future – achieving a defined goal

from user’s aspect

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結論 (cont.) (Source: Dr. William C.Y. Le

e)

• 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