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Wireless technologies

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  • 52
  • PDC – Personal Digital Cellular PDC-P - PDC Packet
  • 802.11b ratified in1999 802.11a 802.11g 802.20 QOS, VoIP, Video, vehicle speeds up to 250kph BlueTooth PAN GSM GPRS 3G
  • Transcript

    • 1. Wireless Technologies
    • 2. Outline
      • Wireless technology overview
      • Cellular communications
      • Satellite systems
      • Wireless LAN
        • 802.11, Bluetooth, UWB
      • Mobility support
        • WAP
      • Wireless applications
    • 3. Why Wireless?
      • Human freedom
        • Portability v. Mobility
      • Objective: “anything, anytime, anywhere”
      • Mobility
        • Size, weight, power
        • Functionality
        • Content
      • Infrastructure required
      • Cost
        • Capital, operational
    • 4. Worldwide Mobile Subscribers SOURCE: CTIA, iGillottResearch, 2001
    • 5. Electromagnetic Spectrum SOURCE: JSC.MIL SOUND LIGHT RADIO HARMFUL RADIATION VHF = VERY HIGH FREQUENCY UHF = ULTRA HIGH FREQUENCY SHF = SUPER HIGH FREQUENCY EHF = EXTRA HIGH FREQUENCY UWB 3.1-10.6 GHz 4G CELLULAR 56-100 GHz 3G CELLULAR 1.5-5.2 GHz 1G, 2G CELLULAR 0.4-1.5GHz
    • 6. MOBILE FIXED MARITIME MOBILE BROADCAST AERO RADIOLOCATION
    • 7. Wireless Telephony SOURCE: IEC.ORG AIR LINK PUBLIC SWITCHED TELEPHONE NETWORK WIRELESS WIRED
    • 8. Cell Clusters SOURCE: IEC.ORG CELL 1 OVERLAPS 6 OTHERS DIFFERENT FREQUENCIES MUST BE USED IN ADJACENT CELLS SEVEN DIFFERENT SETS OF FREQUENCIES REQUIRED ACTUAL COVERAGE AREA OF CELL 1 ACTUAL COVERAGE AREA OF CELL 3
    • 9. 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
    • 10. 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 B x y z ANIMATION
    • 11. Cell Sizes GSM: 100m - 50 km 250 km/hr MACROCELL: $1M MICROCELL: $250K SLOW-MOVING SUBSCRIBERS FAST-MOVING SUBSCRIBERS PICOCELLS
    • 12. 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”
    • 13. Frequency Division Multiplexing (FDMA)
      • Advantages :
      • No dynamic coordination
      • Disadvantages:
      • Inflexible & inefficient if channel load is dynamic and uneven
      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 k 2 k 3 k 4 k 5 k 6 k 1 f t c
    • 14. 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 k 2 k 3 k 4 k 5 k 6 k 1 f t c FREQUENCY BAND
    • 15. Combining TDMA and FDMA 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 f t c k 2 k 3 k 4 k 5 k 6 k 1
    • 16. Time-Division Multiple Access SOURCE: QUALCOMM
    • 17. 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
      k 2 k 3 k 4 k 5 k 6 k 1 f t c
    • 18. 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) 40-400 Kbps
      • Third
        • Digital, packet-switched , wideband CDMA (UMTS) 0.4 – 2 Mbps
      • Fourth
        • Data rate 100 Mbps; achieves “telepresence”
    • 19. GSM Architecture SOURCE: UWC DATA RATE: 9.6 Kbps 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
    • 20. 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 "email" address
        • SMTP Interface
          • Only in the US, not the rest of the world
          • Allows messages to be sent for free!
        • [email_address]
      • 1 BILLION SMS/day worldwide
      SOURCE: GEMBROOK SYSTEMS Yes 140 bytes iDEN Yes 256 bytes CDMA No 160 bytes TDMA/PDC Yes 160 bytes GSM 2 way? Message Length Technology
    • 21. SMS in Banking SOURCE: GEMBROOK SYSTEMS Credit card used Joe’s HiFi $1245 Bank Back-end Systems Internet Bank Web Site Message from YourBank: Credit card purchase of $1245 at Joe’s HiFi. Message appears within seconds on the customer’s phone SMS Monitoring Application Customer Alert me to all credit card transactions greater than $100. Cell Tower Air Wireless Carrier SMS Carrier
    • 22. Satellite Systems SOURCE: WASHINGTON UNIV. 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 GEO M EO LEO
    • 23. Geostationary Orbit SOURCE: BILL LUTHER, FCC
    • 24. GPS Satellite Constellation
      • Global Positioning System
      • Operated by USAF
      • 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
    • 25. GPS Trilateration DISTANCE MEASUREMENTS MUST BE VERY PRECISE LIGHT TRAVELS 1018 FEET EACH MICROSECOND SOURCE: PETER DANA
    • 26. 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
    • 27. Location-Aware Applications
      • Vehicle tracking
      • Firemen in buildings, vital signs, oxygen remaining
      • Asset tracking
      • Baggage
      • Shoppers assistance
      • Robots
      • Corporate visitors
      • Insurance
      • Barges
    • 28. 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
      • 802.11 from 2 Mb to 54 Mb
      • Bluetooth
      • UWB
    • 29. Wireless LAN Components SOURCE: LUCENT WavePOINT II Transmitter Extended Range Antenna Ethernet Converter 11 Mbps WaveLAN PCMCIA Card WaveLAN ISA (Industry Standard Architecture) Card
    • 30. Wireless LAN Configurations SOURCE: PROXIM.COM WIRELESS PEER-TO-PEER CLIENT AND ACCESS POINT MULTIPLE ACCESS POINTS + ROAMING BRIDGING WITH DIRECTIONAL ANTENNAS UP TO 17 KM !
    • 31. 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
    • 32. 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.
    • 33. Bluetooth Devices NOKIA 9110 + FUJI DIGITAL CAMERA ERICSSON COMMUNICATOR ERICSSON R520 GSM 900/1800/1900 ALCATEL One Touch TM 700 GPRS, WAP ERICSSON BLUETOOTH CELLPHONE HEADSET
    • 34. 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
    • 35. Bluetooth Scatternets Slave Piconet ScatterNet Master / Slave SOURCE: KRISHNA BHOUTIKA Master Scatternet Piconets
    • 36. 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
      SOURCE: TIME DOMAIN Spread Spectrum 500 ps Time Randomized Time Coding Amplitude     ps “ 0” “ 1” Power Spectral Density (dB) -80 -40 0 Frequency (GHz) 1 2 3 4 5 Frequency (GHz) Random noise signal
    • 37. 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
    • 38. 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
    • 39. WAP Applications Web Content Server Mobile Terminal WAP Gateway Non Mobile Internet User Database Server SOURCE: DANET WAP simulator iNexware Mobile Network Internet
    • 40. iMode
      • Telephone, pager, email, browser, location tracking, banking , airline tickets , entertainment tickets , games
      • NTT DoCoMo ( ドコモ means “anywhere”)
      • Japan is the wireless Internet leader:
      SOURCE: EUROTECHNOLOGY JAPAN K.K. iMode FAQ
    • 41. 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.COM
    • 42. 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 , NTT
    • 43. iMode Operation DoCoMo Packet Network (PDC-P) iMode Servers PACKET DATA HTTP SOURCE: SAITO & SHIN IP IP INFO PROVIDER INTERNET BILLING DB USER DB
    • 44.
      • 802.11b (2.4 GHz 300’ radius 11 Mbps)
      • 802.11a (5 GHz 54 Mbps incompatible with b)
      • 802.11g (2.4 GHz 54 Mbps backward compatible with b)
      • 802.20 (<3.5 GHz >1 Mbps @250 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
      Wireless Standards SOURCE: JOHN DOWNARD
    • 45. 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
    • 46. Q A &
    • 47. Code Division SOURCE: JOCHEN SCHILLER 1 1 0 DATA 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 “ CODE” 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 DATA  CODE +1 -1 ACTUAL SIGNAL
    • 48. Code Division SOURCE: JOCHEN SCHILLER 1 0 0 DATA B 0 1 1 0 0 1 1 1 0 1 0 0 0 1 0 1 0 0 “ CODE” B 1 0 0 1 0 0 0 1 1 1 1 1 0 0 1 0 1 1 DATA  CODE +1 -1 ACTUAL SIGNAL B
    • 49. Two CDMA Signals SOURCE: JOCHEN SCHILLER ACTUAL SIGNAL A+B +2 -2 +1 -1 ACTUAL SIGNAL A +1 -1 ACTUAL SIGNAL B
    • 50. Recovering Data A From A+B SOURCE: JOCHEN SCHILLER +2 -2 -(A+B) * CODE A +1 -1 INTEGRAL 1 0 1 +2 -2 ACTUAL SIGNAL A+B 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 “ CODE” A