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20-751 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless Technologies.

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Presentation on theme: "20-751 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless Technologies."— Presentation transcript:

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2 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless Technologies

3 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Outline Wireless technology overview Cellular communications Satellite systems Wireless LAN –802.11, Bluetooth, UWB Mobility support –WAP Wireless applications

4 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Why Wireless? Human freedom –Portability v. Mobility Objective: anything, anytime, anywhere Mobility –Size, weight, power –Functionality –Content Infrastructure required Cost –Capital, operational

5 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Worldwide Mobile Subscribers SOURCE: CTIA, iGillottResearch, 2001

6 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Electromagnetic Spectrum SOURCE: JSC.MILJSC.MIL SOUND LIGHT RADIO HARMFUL RADIATION VHF = VERY HIGH FREQUENCY UHF = ULTRA HIGH FREQUENCY SHF = SUPER HIGH FREQUENCY EHF = EXTRA HIGH FREQUENCY 4G CELLULAR GHz 3G CELLULAR GHz 1G, 2G CELLULAR GHz UWB GHz

7 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS MOBILE FIXED MARITIME MOBILE BROADCAST AERO RADIOLOCATION

8 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless Telephony SOURCE: IEC.ORGIEC.ORG AIR LINK PUBLIC SWITCHED TELEPHONE NETWORK WIRED

9 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Cell Clusters SOURCE: IEC.ORGIEC.ORG ACTUAL COVERAGE AREA OF CELL 1 ACTUAL COVERAGE AREA OF CELL 3 CELL 1 OVERLAPS 6 OTHERS DIFFERENT FREQUENCIES MUST BE USED IN ADJACENT CELLS SEVEN DIFFERENT SETS OF FREQUENCIES REQUIRED

10 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Space Division Multiple Access (SDMA) PATTERN CAN BE REPLICATED OVER THE ENTIRE EARTH 200 FREQUENCIES IN ONE CELL TOTAL NUM BER OF FREQUENCIES = 1400 WORLDWIDE MANY CELLS CAN SHARE SAME FREQUENCIES IF SEPARATED IN SPACE

11 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Cell Handover SOURCE: R. C. LEVINE, SMU AS PHONE MOVES FROM CELL A TO CELL B: CELL A MUST HAND THE CALL OVER TO B PHONE MUST CHANGE FREQUENCIES CELL A MUST STOP TRANSMITTING Minimum performance contour Handover threshold contour A Bxy z ANIMATION

12 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Cell Sizes MACROCELL: $1M MICROCELL: $250K SLOW-MOVING SUBSCRIBERS FAST-MOVING SUBSCRIBERS PICOCELLS GSM: 100m - 50 km 250 km/hr

13 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Multiple Access Many users sharing a resource at the same time Needed because user must share cells FDMA (frequency division) –Use different frequencies TDMA (time division) –Use same frequency, different times CDMA (code division) –Use same frequency, same time, different codes

14 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Frequency Division Multiplexing (FDMA) Advantages: No dynamic coordination Disadvantages: Inflexible & inefficient if channel load is dynamic and uneven k2k2 k3k3 k4k4 k5k5 k6k6 k1k1 f t c Each channel gets a band (range) of frequencies Used in traditional radio, TV, 1G cellular EACH CHANNEL OCCUPIES SAME FREQUENCY AT ALL TIMES SOURCE: NORMAN SADEH

15 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS k2k2 k3k3 k4k4 k5k5 k6k6 k1k1 Time Division Multiplexing (TDMA) Each channel gets entire spectrum for a certain (rotating) time period Advantage: Can assign more time to senders with heavier loads 3X capacity of FDMA, 1/3 of power consumption Disadvantage: Requires precise synchronization SOURCE: NORMAN SADEH f t c FREQUENCY BAND

16 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Combining TDMA and FDMA f t c k2k2 k3k3 k4k4 k5k5 k6k6 k1k1 Each channel gets a certain frequency band for a certain amount of time. Example: GSM Advantages: More robust against frequency- selective interference Much greater capacity with time compression Inherent tapping protection Disadvantages Frequency changes must be coordinated SOURCE: NORMAN SADEH

17 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Time-Division Multiple Access SOURCE: QUALCOMMQUALCOMM

18 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Code Division Multiplexing (CDMA) Each channel has unique code All channels use same spectrum at same time but orthogonal codes Advantages: –bandwidth efficient – code space is huge –no coordination or synchronization between different channels –resists interference and tapping –3X capacity of TDMA, 1/25 power consumption Disadvantages: –more complex signal regeneration Implemented using spread spectrum k2k2 k3k3 k4k4 k5k5 k6k6 k1k1 f t c

19 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Cellular Generations First –Analog, circuit-switched (AMPS) Second –Digital, circuit-switched (GSM, Palm) 10 Kbps Advanced second –Digital, circuit switched, Internet-enabled (WAP) 10 Kbps 2.5 –Digital, packet-switched, TDMA (GPRS, EDGE) Kbps Third –Digital, packet-switched, wideband CDMA (UMTS) 0.4 – 2 Mbps Fourth –Data rate 100 Mbps; achieves telepresence

20 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS GSM Architecture SOURCE: UWC LIST OF ROAMING VISITORS LIST OF SUBSCRIBERS IN THIS AREA STOLEN, BROKEN CELLPHONE LIST ENCRYPTION, AUTHENTICATION INTERFACE TO LAND TELEPHONE NETWORKS HIERARCHY OF CELLS CELL TRANSMITTER & RECEIVER PHONE SIM: IDENTIFIES A SUBSCRIBER DATA RATE: 9.6 Kbps

21 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS SMS – Short Message Service Integral part of GSM standard –Added to other standards as well Uses control channel of phone –Send/Receive short text messages –Sender pays (if from mobile phone) Phone has " " address –SMTP Interface Only in the US, not the rest of the world Allows messages to be sent for free! 1 BILLION SMS/day worldwide TechnologyMessage Length 2 way? GSM160 bytesYes TDMA/PDC160 bytesNo CDMA256 bytesYes iDEN140 bytesYes SOURCE: GEMBROOK SYSTEMS

22 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS SMS in Banking Credit card used Joes HiFi $1245 Bank Back-end Systems Internet Bank Web Site Message from YourBank: Credit card purchase of $1245 at Joes HiFi. Message appears within seconds on the customers phone SMS Monitoring Application Customer Alert me to all credit card transactions greater than $100. Cell Tower Air Wireless Carrier SMS Carrier SOURCE: GEMBROOK SYSTEMS

23 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Satellite Systems SOURCE: WASHINGTON UNIV.WASHINGTON UNIV. GEO M EO LEO GEO (22,300 mi., equatorial) high bandwidth, power, latency MEO high bandwidth, power, latency LEO (400 mi.) low power, latency more satellites small footprint V-SAT (Very Small Aperture) private WAN SATELLITE MAP

24 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Geostationary Orbit SOURCE: BILL LUTHER, FCCBILL LUTHER, FCC

25 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS GPS Satellite Constellation Global Positioning System Operated by USAFUSAF 28 satellites 6 orbital planes at a height of 20,200 km Positioned so a minimum of 5 satellites are visible at all times Receiver measures distance to satellite SOURCE: NAVSTAR

26 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS GPS Trilateration DISTANCE MEASUREMENTS MUST BE VERY PRECISE LIGHT TRAVELS 1018 FEET EACH MICROSECOND SOURCE: PETER DANA

27 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Automatic Vehicle Location (AVL) SOURCE: TRIMBLE NAVIGATION Benefits of AVL Fast dispatch Customer service Safety, security Digital messaging Dynamic route optimization Driver compliance Sample AVL Users Chicago 911 Inkombank, Moscow Taxi companies Intelligent Highway demo CA

28 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Location-Aware Applications Vehicle tracking Firemen in buildings, vital signs, oxygen remaining Asset tracking Baggage Shoppers assistance Robots Corporate visitors Insurance Barges

29 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless LAN Idea: just a LAN, but without wires Not as easy since signals are of limited range –Unlike wired LAN, if A can hear B and B can hear C, not necessarily true that A can hear C Uses unlicensed frequencies, low power from 2 Mb to 54 Mb Bluetooth UWB

30 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless LAN Components SOURCE: LUCENT WavePOINT II Transmitter Extended Range Antenna Ethernet Converter 11 Mbps WaveLAN PCMCIA Card WaveLAN ISA (Industry Standard Architecture) Card

31 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless LAN Configurations SOURCE: PROXIM.COMPROXIM.COM WIRELESS PEER-TO-PEER CLIENT AND ACCESS POINT MULTIPLE ACCESS POINTS + ROAMING BRIDGING WITH DIRECTIONAL ANTENNAS UP TO 17 KM !

32 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Bluetooth A standard permitting for wireless connection of: Personal computers Printers Mobile phones Handsfree headsets LCD projectors Modems Wireless LAN devices Notebooks Desktop PCs PDAs

33 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Bluetooth Characteristics Operates in the 2.4 GHz Industrial-Scientific-Medical (ISM) (unlicensed)! band. Packet switched. 1 milliwatt (as opposed to 500 mW cellphone. Low cost. 10m to 100m range Uses Frequency Hop (FH) spread spectrum, which divides the frequency band into a number of hop channels. During connection, devices hop from one channel to another 1600 times per second Bandwidth 1-2 megabits/second Supports up to 8 devices in a piconet (two or more Bluetooth units sharing a channel). Built-in security. Non line-of-sight transmission through walls and briefcases. Easy integration of TCP/IP for networking.

34 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Bluetooth Devices NOKIA FUJI DIGITAL CAMERA ERICSSON COMMUNICATOR ERICSSON R520 GSM 900/1800/1900 ALCATEL One Touch TM 700 GPRS, WAP ERICSSON BLUETOOTH CELLPHONE HEADSET

35 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Bluetooth Piconets Piconet = small area network Ad hoc network: no predefined structure Based on available nodes and their locations Formed (and changed) in real time

36 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Bluetooth Scatternets Master Slave Piconet ScatterNet Master / Slave Scatternet Piconets SOURCE: KRISHNA BHOUTIKAKRISHNA BHOUTIKA

37 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Time-Modulated Ultra-Wideband (TM-UWB) Not a sinewave, but millions of pulses per second Time coded to make noise-like signal Pulse position modulation 500 ps Time Randomized Time Coding Amplitude ps 01 Power Spectral Density (dB) Frequency (GHz) Random noise signal SOURCE: TIME DOMAIN Spread Spectrum

38 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Ultra Wideband Properties VERY low power: 0.01 milliwatt –Bluetooth 1 milliwatt (100 x UWB) –Cellphone 500 milliwatts (50,000 x UWB) Range: 30 to 300 feet Very small Low cost 100 Mbits/second Up to 500 Mbps for short distances (USB speed) No interference Secure PulsON, A Chip Based Solution

39 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless Application Support WAP (Wireless Application Protocol) and iMode High-level protocols that use cellular transport WAP: –Uses WML (Wireless Markup Language) –Divides content into cards equal to one telephone screen –Simplified but incompatible form of HTML –To send to a WAP phone, must broadcast WML content

40 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS WAP Applications Web Content Server Mobile Terminal Mobile Network Internet WAP Gateway Non Mobile Internet User Database Server SOURCE: DANET WAP simulator iNexware

41 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS iMode Telephone, pager, , browser, location tracking, banking, airline tickets, entertainment tickets, games bankingairline ticketsentertainment tickets NTT DoCoMo ( means anywhere) Japan is the wireless Internet leader: SOURCE: EUROTECHNOLOGY JAPAN K.K. iMode FAQFAQ

42 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS iMode Sits on top of packet voice/data transport As of July 31, 2003, > 39 million subscribers –28,000 new ones per day 26% of Japan >3000 official sites >1000 application partners >40,000 unofficial sites Fee based on amount of data transmitted SOURCES: XML.COM, EUROTECHNOLOGY.COMXML.COMEUROTECHNOLOGY.COM

43 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS iMode Phonetic text input (better for Japanese) SLOW: 9.6 Kbps, but 3G will raise to 384 K Uses cHTML (compact HTML) –same rendering model as HTML (whole page at a time) –low memory footprint (no tables or frames) Standby time: 400 min., device weight 2.4 oz. (74g) SOURCES: XML.COM, NTTXML.COMNTT

44 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS iMode Operation IP DoCoMoPacketNetwork(PDC-P) INFO PROVIDER INTERNET iMode Servers BILLING DB USER DB PACKET DATA HTTP SOURCE: SAITO & SHIN

45 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Wireless Standards b (2.4 GHz 300 radius 11 Mbps) a (5 GHz 54 Mbps incompatible with b) g (2.4 GHz 54 Mbps backward compatible with b) ( 1 kph) BlueTooth (2.4 Ghz 30 radius) GSM (9.6 Kbps) GPRS (28.8 Kbps up to 60 Kbps ) 3G (UMTS 1.1 Mbit/s shared typically giving 80 Kbit/s ) 4G 2010? (10 Mbs? ) UWB potential to deliver 500 Mbps over short distances SOURCE: JOHN DOWNARDJOHN DOWNARD

46 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Key Takeaways Mobile growing very rapidly Cell systems need large infrastructure Wireless LAN does not Content preparation is a problem Wireless business models largely unexplored Bandwidth, bandwidth, bandwidth

47 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Q A &

48 Code Division SOURCE: JOCHEN SCHILLER 110DATA CODE DATA CODE +1 ACTUAL SIGNAL

49 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Code Division SOURCE: JOCHEN SCHILLER 100DATA B CODE B DATA CODE +1 ACTUAL SIGNAL B

50 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Two CDMA Signals SOURCE: JOCHEN SCHILLER +1 ACTUAL SIGNAL A +1 ACTUAL SIGNAL B ACTUAL SIGNAL A+B +2 -2

51 ECOMMERCE TECHNOLOGY FALL 2003 COPYRIGHT © 2003 MICHAEL I. SHAMOS Recovering Data A From A+B SOURCE: JOCHEN SCHILLER ACTUAL SIGNAL A+B CODE A (A+B) * CODE A +1 INTEGRAL 1 0 1


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