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
  • Wireless technologies

    1. 1. Wireless Technologies
    2. 2. Outline <ul><li>Wireless technology overview </li></ul><ul><li>Cellular communications </li></ul><ul><li>Satellite systems </li></ul><ul><li>Wireless LAN </li></ul><ul><ul><li>802.11, Bluetooth, UWB </li></ul></ul><ul><li>Mobility support </li></ul><ul><ul><li>WAP </li></ul></ul><ul><li>Wireless applications </li></ul>
    3. 3. Why Wireless? <ul><li>Human freedom </li></ul><ul><ul><li>Portability v. Mobility </li></ul></ul><ul><li>Objective: “anything, anytime, anywhere” </li></ul><ul><li>Mobility </li></ul><ul><ul><li>Size, weight, power </li></ul></ul><ul><ul><li>Functionality </li></ul></ul><ul><ul><li>Content </li></ul></ul><ul><li>Infrastructure required </li></ul><ul><li>Cost </li></ul><ul><ul><li>Capital, operational </li></ul></ul>
    4. 4. Worldwide Mobile Subscribers SOURCE: CTIA, iGillottResearch, 2001
    5. 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. 6. MOBILE FIXED MARITIME MOBILE BROADCAST AERO RADIOLOCATION
    7. 7. Wireless Telephony SOURCE: IEC.ORG AIR LINK PUBLIC SWITCHED TELEPHONE NETWORK WIRELESS WIRED
    8. 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. 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. 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. 11. Cell Sizes GSM: 100m - 50 km 250 km/hr MACROCELL: $1M MICROCELL: $250K SLOW-MOVING SUBSCRIBERS FAST-MOVING SUBSCRIBERS PICOCELLS
    12. 12. Multiple Access <ul><li>Many users sharing a resource at the “same time” </li></ul><ul><li>Needed because user must share cells </li></ul><ul><li>FDMA (frequency division) </li></ul><ul><ul><li>Use different frequencies </li></ul></ul><ul><li>TDMA (time division) </li></ul><ul><ul><li>Use same frequency, different times </li></ul></ul><ul><li>CDMA (code division) </li></ul><ul><ul><li>Use same frequency, same time, different “codes” </li></ul></ul>
    13. 13. Frequency Division Multiplexing (FDMA) <ul><li>Advantages : </li></ul><ul><li>No dynamic coordination </li></ul><ul><li>Disadvantages: </li></ul><ul><li>Inflexible & inefficient if channel load is dynamic and uneven </li></ul>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. 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. 15. Combining TDMA and FDMA Each channel gets a certain frequency band for a certain amount of time. Example: GSM <ul><li>Advantages: </li></ul><ul><li>More robust against frequency- selective interference </li></ul><ul><li>Much greater capacity with time compression </li></ul><ul><li>Inherent tapping protection </li></ul><ul><li>Disadvantages </li></ul><ul><li>Frequency changes must be coordinated </li></ul>SOURCE: NORMAN SADEH f t c k 2 k 3 k 4 k 5 k 6 k 1
    16. 16. Time-Division Multiple Access SOURCE: QUALCOMM
    17. 17. Code Division Multiplexing (CDMA) <ul><li>Each channel has unique “code” </li></ul><ul><li>All channels use same spectrum at same time but orthogonal codes </li></ul><ul><li>Advantages: </li></ul><ul><ul><li>bandwidth efficient – code space is huge </li></ul></ul><ul><ul><li>no coordination or synchronization between different channels </li></ul></ul><ul><ul><li>resists interference and tapping </li></ul></ul><ul><ul><li>3X capacity of TDMA, 1/25 power consumption </li></ul></ul><ul><li>Disadvantages: </li></ul><ul><ul><li>more complex signal regeneration </li></ul></ul><ul><li>Implemented using spread spectrum </li></ul>k 2 k 3 k 4 k 5 k 6 k 1 f t c
    18. 18. Cellular Generations <ul><li>First </li></ul><ul><ul><li>Analog, circuit-switched (AMPS) </li></ul></ul><ul><li>Second </li></ul><ul><ul><li>Digital, circuit-switched (GSM, Palm) 10 Kbps </li></ul></ul><ul><li>Advanced second </li></ul><ul><ul><li>Digital, circuit switched , Internet-enabled (WAP) 10 Kbps </li></ul></ul><ul><li>2.5 </li></ul><ul><ul><li>Digital, packet-switched , TDMA (GPRS, EDGE) 40-400 Kbps </li></ul></ul><ul><li>Third </li></ul><ul><ul><li>Digital, packet-switched , wideband CDMA (UMTS) 0.4 – 2 Mbps </li></ul></ul><ul><li>Fourth </li></ul><ul><ul><li>Data rate 100 Mbps; achieves “telepresence” </li></ul></ul>
    19. 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. 20. SMS – Short Message Service <ul><li>Integral part of GSM standard </li></ul><ul><ul><li>Added to other standards as well </li></ul></ul><ul><li>Uses control channel of phone </li></ul><ul><ul><li>Send/Receive short text messages </li></ul></ul><ul><ul><li>Sender pays (if from mobile phone) </li></ul></ul><ul><li>Phone has &quot;email&quot; address </li></ul><ul><ul><li>SMTP Interface </li></ul></ul><ul><ul><ul><li>Only in the US, not the rest of the world </li></ul></ul></ul><ul><ul><ul><li>Allows messages to be sent for free! </li></ul></ul></ul><ul><ul><li>[email_address] </li></ul></ul><ul><li>1 BILLION SMS/day worldwide </li></ul>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. 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. 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. 23. Geostationary Orbit SOURCE: BILL LUTHER, FCC
    24. 24. GPS Satellite Constellation <ul><li>Global Positioning System </li></ul><ul><li>Operated by USAF </li></ul><ul><li>28 satellites </li></ul><ul><li>6 orbital planes at a height of 20,200 km </li></ul><ul><li>Positioned so a minimum of 5 satellites are visible at all times </li></ul><ul><li>Receiver measures distance to satellite </li></ul>SOURCE: NAVSTAR
    25. 25. GPS Trilateration DISTANCE MEASUREMENTS MUST BE VERY PRECISE LIGHT TRAVELS 1018 FEET EACH MICROSECOND SOURCE: PETER DANA
    26. 26. Automatic Vehicle Location (AVL) SOURCE: TRIMBLE NAVIGATION <ul><li>Benefits of AVL </li></ul><ul><li>Fast dispatch </li></ul><ul><li>Customer service </li></ul><ul><li>Safety, security </li></ul><ul><li>Digital messaging </li></ul><ul><li>Dynamic route optimization </li></ul><ul><li>Driver compliance </li></ul><ul><li>Sample AVL Users </li></ul><ul><li>Chicago 911 </li></ul><ul><li>Inkombank, Moscow </li></ul><ul><li>Taxi companies </li></ul>Intelligent Highway demo CA
    27. 27. Location-Aware Applications <ul><li>Vehicle tracking </li></ul><ul><li>Firemen in buildings, vital signs, oxygen remaining </li></ul><ul><li>Asset tracking </li></ul><ul><li>Baggage </li></ul><ul><li>Shoppers assistance </li></ul><ul><li>Robots </li></ul><ul><li>Corporate visitors </li></ul><ul><li>Insurance </li></ul><ul><li>Barges </li></ul>
    28. 28. Wireless LAN <ul><li>Idea: just a LAN, but without wires </li></ul><ul><li>Not as easy since signals are of limited range </li></ul><ul><ul><li>Unlike wired LAN, if A can hear B and B can hear C, not necessarily true that A can hear C </li></ul></ul><ul><li>Uses unlicensed frequencies, low power </li></ul><ul><li>802.11 from 2 Mb to 54 Mb </li></ul><ul><li>Bluetooth </li></ul><ul><li>UWB </li></ul>
    29. 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. 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. 31. Bluetooth <ul><li> A standard permitting for wireless connection of: </li></ul><ul><li>Personal computers </li></ul><ul><li>Printers </li></ul><ul><li>Mobile phones </li></ul><ul><li>Handsfree headsets </li></ul><ul><li>LCD projectors </li></ul><ul><li>Modems </li></ul><ul><li>Wireless LAN devices </li></ul><ul><li>Notebooks </li></ul><ul><li>Desktop PCs </li></ul><ul><li>PDAs </li></ul>
    32. 32. Bluetooth Characteristics <ul><li>Operates in the 2.4 GHz Industrial-Scientific-Medical (ISM) (unlicensed)! band. Packet switched. 1 milliwatt (as opposed to 500 mW cellphone. Low cost. </li></ul><ul><li>10m to 100m range </li></ul><ul><li>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 </li></ul><ul><li>Bandwidth 1-2 megabits/second </li></ul><ul><li>Supports up to 8 devices in a piconet (two or more Bluetooth units sharing a channel). </li></ul><ul><li>Built-in security. </li></ul><ul><li>Non line-of-sight transmission through walls and briefcases. </li></ul><ul><li>Easy integration of TCP/IP for networking. </li></ul>
    33. 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. 34. Bluetooth Piconets <ul><li>Piconet = small area network </li></ul><ul><li>“ Ad hoc” network: no predefined structure </li></ul><ul><li>Based on available nodes and their locations </li></ul><ul><li>Formed (and changed) in real time </li></ul>
    35. 35. Bluetooth Scatternets Slave Piconet ScatterNet Master / Slave SOURCE: KRISHNA BHOUTIKA Master Scatternet Piconets
    36. 36. Time-Modulated Ultra-Wideband (TM-UWB) <ul><li>Not a sinewave, but millions of pulses per second </li></ul><ul><li>Time coded to make noise-like signal </li></ul><ul><li>Pulse position modulation </li></ul>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. 37. Ultra Wideband Properties <ul><li>VERY low power: 0.01 milliwatt </li></ul><ul><ul><li>Bluetooth 1 milliwatt (100 x UWB) </li></ul></ul><ul><ul><li>Cellphone 500 milliwatts (50,000 x UWB) </li></ul></ul><ul><li>Range: 30 to 300 feet </li></ul><ul><li>Very small </li></ul><ul><li>Low cost </li></ul><ul><li>100 Mbits/second </li></ul><ul><li>Up to 500 Mbps for short distances (USB speed) </li></ul><ul><li>No interference </li></ul><ul><li>Secure </li></ul>PulsON, A Chip Based Solution
    38. 38. Wireless Application Support <ul><li>WAP (Wireless Application Protocol) and iMode </li></ul><ul><li>High-level protocols that use cellular transport </li></ul><ul><li>WAP: </li></ul><ul><ul><li>Uses WML (Wireless Markup Language) </li></ul></ul><ul><ul><li>Divides content into “cards” equal to one telephone screen </li></ul></ul><ul><ul><li>Simplified but incompatible form of HTML </li></ul></ul><ul><ul><li>To send to a WAP phone, must broadcast WML content </li></ul></ul>
    39. 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. 40. iMode <ul><li>Telephone, pager, email, browser, location tracking, banking , airline tickets , entertainment tickets , games </li></ul><ul><li>NTT DoCoMo ( ドコモ means “anywhere”) </li></ul><ul><li>Japan is the wireless Internet leader: </li></ul>SOURCE: EUROTECHNOLOGY JAPAN K.K. iMode FAQ
    41. 41. iMode <ul><li>Sits on top of packet voice/data transport </li></ul><ul><li>As of July 31, 2003, > 39 million subscribers </li></ul><ul><ul><li>28,000 new ones per day </li></ul></ul><ul><li>26% of Japan </li></ul><ul><li>>3000 “official” sites </li></ul><ul><li>>1000 application partners </li></ul><ul><li>>40,000 unofficial sites </li></ul><ul><li>Fee based on amount of data transmitted </li></ul>SOURCES: XML.COM , EUROTECHNOLOGY.COM
    42. 42. iMode <ul><li>Phonetic text input (better for Japanese) </li></ul><ul><li>SLOW: 9.6 Kbps, but 3G will raise to 384 K </li></ul><ul><li>Uses cHTML (compact HTML) </li></ul><ul><ul><li>same rendering model as HTML (whole page at a time) </li></ul></ul><ul><ul><li>low memory footprint (no tables or frames) </li></ul></ul><ul><li>Standby time: 400 min., device weight 2.4 oz. (74g) </li></ul>SOURCES: XML.COM , NTT
    43. 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. 44. <ul><li>802.11b (2.4 GHz 300’ radius 11 Mbps) </li></ul><ul><li>802.11a (5 GHz 54 Mbps incompatible with b) </li></ul><ul><li>802.11g (2.4 GHz 54 Mbps backward compatible with b) </li></ul><ul><li>802.20 (<3.5 GHz >1 Mbps @250 kph) </li></ul><ul><li>BlueTooth (2.4 Ghz 30’ radius) </li></ul><ul><li>GSM (9.6 Kbps) GPRS (28.8 Kbps up to 60 Kbps ) </li></ul><ul><li>3G (UMTS 1.1 Mbit/s shared typically giving 80 Kbit/s ) </li></ul><ul><li>4G 2010? (10 Mbs? ) </li></ul><ul><li>UWB potential to deliver 500 Mbps over short distances </li></ul>Wireless Standards SOURCE: JOHN DOWNARD
    45. 45. Key Takeaways <ul><li>Mobile growing very rapidly </li></ul><ul><li>Cell systems need large infrastructure </li></ul><ul><li>Wireless LAN does not </li></ul><ul><li>Content preparation is a problem </li></ul><ul><li>Wireless business models largely unexplored </li></ul><ul><li>Bandwidth, bandwidth, bandwidth </li></ul>
    46. 46. Q A &
    47. 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. 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. 49. Two CDMA Signals SOURCE: JOCHEN SCHILLER ACTUAL SIGNAL A+B +2 -2 +1 -1 ACTUAL SIGNAL A +1 -1 ACTUAL SIGNAL B
    50. 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

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