Introduction to RF & Wireless - Part 4

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Part 4 covers broadband wireless systems, wireless networks, mobile internet and future wireless systems

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Introduction to RF & Wireless - Part 4

  1. 1. Introduction to RF & Wireless Two Day Seminar Module 4
  2. 2. Course AgendaDay One • Morning (Module 1) – Introduction to RF • Afternoon (Module 2) – RF hardwareDay Two • Morning (Module 3) – Older systems & mobile telephony • Afternoon (Module 4) – Newer systems & the future
  3. 3. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  4. 4. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  5. 5. 1. Broadband Fixed Wireless ChoicesAir Link Transmission Technologies
  6. 6. 1. Broadband Fixed Wireless ChoicesAir Link Transmission Technologies
  7. 7. Local Loop Wireless local loopTelephone Cablelocal loop local loop Broadband Fixed Wireless - Choices
  8. 8. Local LoopBroadband Fixed Wireless ♦ Exists to compete in the local loop ♦ Used primarily for Internet access ♦ Line of sight is an issue ♦ Multipath is an issue ♦ Two configurations ♦ Four choices Broadband Fixed Wireless - Choices
  9. 9. ConfigurationsPoint-To-Point Broadband Fixed Wireless - Choices
  10. 10. ConfigurationsPoint-To-Multipoint Broadband Fixed Wireless - Choices
  11. 11. ChoicesBroadband Fixed Wireless ♦ MMDS ♦ LMDS ♦ Unlicensed ♦ Wireless fiber Broadband Fixed Wireless - Choices
  12. 12. MMDSMultichannel MultipointDistribution Service ♦ Licensed ♦ 2.6 GHz ♦ 2 Mbps ♦ Point-to-multipoint ♦ 35 miles Broadband Fixed Wireless - Choices
  13. 13. LMDSLocal MultipointDistribution Service ♦ Licensed ♦ 31GHz ♦ 155 Mbps ♦ Point-to-point ♦ 3 miles Broadband Fixed Wireless - Choices
  14. 14. AtmosphericAttenuation
  15. 15. UnlicensedUnlicensed Spread Spectrum ♦ No license required ♦ ISM frequency bands ♦ ??? Mbps ♦ Point-to-point and point-to-multipoint ♦ ??? miles Broadband Fixed Wireless - Choices
  16. 16. ISM Frequency BandsOverview ♦ 900 MHz, 2.4 GHz, 5.8 GHz ♦ Industrial, scientific, medical equipment ♦ 100s of MHz of bandwidth ♦ Limited output power ♦ Must use spread spectrum ♦ Open usage Broadband Fixed Wireless - Choices
  17. 17. UnlicensedGood News ♦ No license requiredBad News ♦ Interference from non-RF items ♦ Interference from RF items ♦ Interference from competitors ♦ Limited output power Broadband Fixed Wireless - Choices
  18. 18. UnlicensedTypicalDeployment t Pt to P H z 5 .8G Pt to Multipoint 2.4 GHz ISP Broadband Fixed Wireless - Choices
  19. 19. UnlicensedOther Issues ♦ Inexpensive RF hardware ♦ Expensive customer premises equipment (CPE) ♦ Questionable market acceptance • Businesses • Single family homes • MDUs and MTUs Broadband Fixed Wireless - Choices
  20. 20. Wireless FiberFree Space Optics ♦ Unlicensed ♦ Infrared frequency ♦ 622 Mbps ♦ Point to point ♦ Less than 1 mile Broadband Fixed Wireless - Choices
  21. 21. Wireless Fiber Transceiver Broadband Fixed Wireless - Choices
  22. 22. Wireless FiberOther Issues ♦ Data rates compete with fiber ♦ Adversely effected by rain and fog ♦ Well defined market • Campuses • Building to building • Emergency bandwidth Broadband Fixed Wireless - Choices
  23. 23. Recap MMDS LMDS Unlicensed Wireless Fiber Frequency 2.6 GHz 31 GHz 900 MHz 10,000 THz 2.4/5.8 GHzConfiguration PmP P2P P2P P2P PmP Range 35 miles 3 miles 25 miles < 1 mile 5 miles Data Rate 2 Mbps 155 Mbps 1 Mbps 622 Mbps 100 Mbps
  24. 24. 1. Broadband Fixed Wireless ChoicesAir Link Transmission Technologies
  25. 25. Air Link Transmission Technologies Challenge ♦ Some wireless services are allocated a single lump of frequency • Unlike cellular ♦ How to do two-way communications Braodband Fixed Wireless - Air Link Transmissi
  26. 26. Two Way CommunicationsSimplex ♦ One frequency ♦ One party transmits at a time • Walkie-talkies Frequency 1 Frequency 1 Braodband Fixed Wireless - Air Link Transmissi
  27. 27. Two Way CommunicationsHalf Duplex ♦ Two frequencies ♦ One party transmits at a time • Wireless LANs Frequency 1 Frequency 2 Braodband Fixed Wireless - Air Link Transmissi
  28. 28. Two Way CommunicationsFull Duplex ♦ Two frequencies ♦ Both parties can transmit at the same time • Cellular phones Frequency 1 Frequency 2 Braodband Fixed Wireless - Air Link Transmissi
  29. 29. Air Link Transmission Technologies What ♦ To make optimum use of available bandwidth ♦ To overcome transmission problems Choices ♦ FDD ♦ TDD ♦ OFDM Braodband Fixed Wireless - Air Link Transmissi
  30. 30. FDDFrequency Division Duplexing ♦ Dividing the allotted frequency into sub-bands ♦ Each sub-band has a designated direction Braodband Fixed Wireless - Air Link Transmissi
  31. 31. FDD ISM bandBraodband Fixed Wireless - Air Link Transmissi
  32. 32. FDDBraodband Fixed Wireless - Air Link Transmissi
  33. 33. FDD + FDMA Braodband Fixed Wireless - Air Link Transmissi
  34. 34. TDDTime Division Duplexing ♦ Dividing the allotted frequency into time slots ♦ Each time slot goes in one of two directions Braodband Fixed Wireless - Air Link Transmissi
  35. 35. TDD ISM bandBraodband Fixed Wireless - Air Link Transmissi
  36. 36. TDDBraodband Fixed Wireless - Air Link Transmissi
  37. 37. Multipath Is A Problem a th Refle cted p Direct path Braodband Fixed Wireless - Air Link Transmissi
  38. 38. So Is Line Of Sight a th Refle cted p Direct path
  39. 39. OFDMOrthogonal Frequency Division Multiplexing ♦ Solves multipath ♦ Deals with Non-Line Of Sight (NLOS) situationsHow ♦ By dividing up a broadband signal into multiple signals • Which slows it down Braodband Fixed Wireless - Air Link Transmissi
  40. 40. OFDMVisually Braodband Fixed Wireless - Air Link Transmissi
  41. 41. OFDM Example
  42. 42. Recap What CommentsFDD Divides a frequency band Good for telephony into sub-bands for two-way communicationsTDD Divides a frequency band Optimum use of into time slots for two-way bandwidth communictionsOFDM Divides a broadband signal To overcome into multiple narrowband multipath and NLOS signals
  43. 43. Broadband Fixed Wireless The end
  44. 44. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  45. 45. 2. Wireless Networks Local Area Networks Personal Area Networks Home Networks
  46. 46. 2. Wireless NetworksLocal Area Networks Personal Area Networks Home Networks
  47. 47. Local Area Networks (LAN)Parameters ♦ Limited area • Floor or campus ♦ Some mobility • Walking around ♦ Server centric Wireless Networks - Local Area Networks
  48. 48. Basic Architecture Wireless Networks - Local Area Networks
  49. 49. Basic ArchitectureBasic Service Set BSS Wireless Networks - Local Area Networks
  50. 50. Basic Architecture BSS BSSExtended Service Set Wireless Networks - Local Area Networks
  51. 51. Access Point Wireless Networks - Local Area Networks
  52. 52. Local Area NetworksFrequency ♦ Unlicensed bands • ISM bandsAir Interface ♦ Mostly Spread spectrum • Direct sequence • Frequency hopping Wireless Networks - Local Area Networks
  53. 53. FHSSFrequency Hopping Spread Spectrum ♦ Uses a PN signal to generate a series of random carrier frequencies • Transmitter and receiver use the same PN signal Wireless Networks - Local Area Networks
  54. 54. FHSSWireless Networks - Local Area Networks
  55. 55. FHSSWireless Networks - Local Area Networks
  56. 56. FHSSWireless Networks - Local Area Networks
  57. 57. FHSSWireless Networks - Local Area Networks
  58. 58. FHSSWireless Networks - Local Area Networks
  59. 59. FHSSWireless Networks - Local Area Networks
  60. 60. FHSSWireless Networks - Local Area Networks
  61. 61. FHSSWireless Networks - Local Area Networks
  62. 62. FHSSWireless Networks - Local Area Networks
  63. 63. FHSSWireless Networks - Local Area Networks
  64. 64. FHSSHow Wireless Networks - Local Area Networks
  65. 65. FHSSHow Wireless Networks - Local Area Networks
  66. 66. ComparisonFHSS vs DSSS ♦ FHSS has better noise immunity ♦ DSSS has higher instantaneous bandwidth • 10 MHz vs 1 MHz ♦ FHSS deals better with multipath Wireless Networks - Local Area Networks
  67. 67. Choices802.11 ♦ Originated in the US ♦ Based in Ethernet ♦ Shared frequencyHiperLAN ♦ Originated in Europe ♦ Based in GSM ♦ Unique frequency
  68. 68. Details System Band Data Rate Technology 802.11 2.4 GHz 2 Mbps FHSS or DSSSWi Fi 802.11b 2.4 GHz 11 Mbps DSSS + CCK 802.11a 5.8 GHz 54 Mbps OFDM HiperLAN 5.8 GHz 20 Mbps GMSK HiperLAN II 5.8 GHz 50 Mbps OFDM Wireless Networks - Local Area Networks
  69. 69. 2. Wireless Networks Local Area NetworksPersonal Area Networks Home Networks
  70. 70. Personal Area Networks (PAN)Parameters ♦ Unlimited area • Where ever you go ♦ Some mobility • Walking around ♦ Person centric • You become the AP Wireless Networks - Personal Area Networks
  71. 71. Personal Area NetworksRequirements ♦ Interoperability • Mobiles talking to mobiles ♦ Short range • Low power/low interference ♦ Self discovery • Auto initiate Wireless Networks - Personal Area Networks
  72. 72. Personal Area NetworksApplications ♦ Impromptu networks Piconet Wireless Networks - Personal Area Networks
  73. 73. Personal Area NetworksApplications ♦ Cell phone as wireless modem Wireless Networks - Personal Area Networks
  74. 74. PAN StandardsBluetooth ♦ Developed by Ericsson (Sweden) ♦ Based on 802.11 ♦ Voice + data ♦ Designated 802.15 ♦ Internationally accepted standard & frequency Wireless Networks - Personal Area Networks
  75. 75. BluetoothParameter SpecificationData Rate 1 Mbps Range 30 feetFrequency 2.4 GHzTechnology FHSS Wireless Networks - Personal Area Networks
  76. 76. 2.4 GHz ReduxWho Uses 2.4 GHz ♦ Microwave ovens ♦ Cordless phones ♦ Broadband fixed wireless providers ♦ Wireless networks ♦ Bluetooth networks
  77. 77. 2. Wireless Networks Local Area Networks Personal Area Networks Home Networks
  78. 78. Home NetworksTwo Systems ♦ HomeRF • For the home ♦ IrDA • For the home and the office Wireless Networks - Home Networks
  79. 79. HomeRFParameters ♦ Limited area • The home ♦ Some mobility • Within the home ♦ Home centric • Information appliances Wireless Networks - Home Networks
  80. 80. HomeRFRequirements ♦ Low cost • Consumer market ♦ Versatile • Data, voice, audio, video ♦ Interoperability • 802.11 + DECT Wireless Networks - Home Networks
  81. 81. HomeRF Vision
  82. 82. Infrared Data Association (IrDa) Parameters ♦ Very limited area • A few feet ♦ Almost no mobility • A few inches ♦ Decentralized • Point to point Wireless Networks - Home Networks
  83. 83. IrDaDescription ♦ An industry standard • For data only • Uses infrared light • Good for about 3 feet ♦ Embedded in most gadgets Wireless Networks - Home Networks
  84. 84. IrDAApplications ♦ Wireless synching Wireless Networks - Personal Area Networks
  85. 85. IrDAApplications ♦ Upload digital photos Wireless Networks - Personal Area Networks
  86. 86. Network Comparison 802.11b Bluetooth HomeRF IrDAFrequency 2.4 GHz 2.4 GHz 2.4 GHz IRTechnology DSSS FHSS FHSS IRRange 300 feet 30 feet 150 feet 3 feetData Rate 11 Mbps 1Mbps 1.6 Mbps 4 MbpsVoice None Some Good NoneNo of nodes 127 8 127 2
  87. 87. Recap Area Mobility CenterLAN Floor Walking ServerPAN Everywhere Walking PersonHome RF Home Walking HomeIrDA Few feet None Decentralized
  88. 88. Wireless Networks The end
  89. 89. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  90. 90. Mobile Internet Wireless Internet
  91. 91. Mobile InternetDefined ♦ Mobile devices • Cell phones, PDAs, laptops ♦ Wide area • City, state, country ♦ High mobility • Driving around speed Mobile Internet - Technology
  92. 92. Mobile InternetChallenges ♦ Data rate • Depends on the device ♦ Screen size • Different content ♦ Ubiquity • I want it everywhere Mobile Internet - Technology
  93. 93. Mobile Internet Candidates Cellular ISM LEOs Mobile Internet - Technology
  94. 94. Mobile Internet Candidates PROS CONSCellular Existing infrastructure Not much bandwidth Existing customer base Need a licenseISM Lots of bandwidth Build from the ground up No license required Limited powerLEOs Use it anywhere Very expensive buildout Heavy frequency reuse Requires more power Mobile Internet - Technology
  95. 95. Mobile InternetInfrastructure Changes ♦ Wireless portion ♦ Internet portion Mobile Internet - Technology
  96. 96. Mobile InternetWireless Infrastructure Changes ♦ Mobile switching center • Gateway for separating voice from data • Packet switching ♦ Mobile device • Microbrowser Mobile Internet - Technology
  97. 97. Mobile InternetPacket Switching ♦ Shared access to a given channel ♦ More efficient use of spectrum ♦ Better for bursty (Internet) traffic ♦ Higher instantaneous data rates Mobile Internet - Technology
  98. 98. Mobile InternetInternet Infrastructure Changes ♦ New markup language • C-HTML (web guys) • WML (phone guys) ♦ Multiple servers (possibly) • Unique content ♦ New protocols • WAP (non-proprietary) Mobile Internet - Technology
  99. 99. Mobile InternetVisually
  100. 100. WAPWireless Access Protocol 1) Wireless Markup Language (WML) • No tables, frames, other fancy stuff 2) Protocols • WDP (wireless datagram protocol) • WTP (wireless transaction protocol) • WSP (wireless session protocol) Mobile Internet - WAP
  101. 101. WAPInfrastructure ♦ WAP gateways • Remote access server for WAP • wap.company.com ♦ WAP servers • Stores WAP data • Some translate pages on the fly Mobile Internet - WAP
  102. 102. WAPVisually WAP WAP Server
  103. 103. WAPWorks ♦ Over all technologies • Mobile telephony • Bluetooth ♦ Over all frequencies • Cellular • PCS • ISM Mobile Internet - WAP
  104. 104. M-CommerceMobile Commerce ♦ A trillion dollar business (some day) ♦ Take advantage of unique aspects of mobility ♦ Not meant to replace e-commerce Mobile Internet - M-Commerce
  105. 105. M-CommercePossibilities ♦ Comparison shopping ♦ Location-specific services ♦ Advertising ♦ Financial transactions ♦ Entertainment Mobile Internet - M-Commerce
  106. 106. Mobile InternetStatus ♦ Cellular • i-Mode in Japan ♦ ISM • Ricochet died ♦ LEOs • Stay tuned Mobile Internet - Status
  107. 107. Mobile Internet The end
  108. 108. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  109. 109. 4. The FutureNew Technologies Security IssuesHealth Concerns
  110. 110. 4. The FutureNew Technologies Security Issues Health Concerns
  111. 111. New TechnologiesFive 1) Ultrawideband 2) MEMS 3) BLAST 4) RFID 5) Telematics The Future - New Technolgoies
  112. 112. UltrawidebandWhat ♦ Periodic single sine wave • Monocycle ♦ Covers multiple licensed bands • Must not interfere ♦ Not yet approved by the FCC The Future - New Technolgoies
  113. 113. UltrawidebandVisually Monocycles The Future - New Technolgoies
  114. 114. UltrawidebandProblem Same frequency The Future - New Technolgoies
  115. 115. UltrawidebandResult The Future - New Technolgoies
  116. 116. UltrawidebandWhat If Time hopping spread spectrum The Future - New Technolgoies
  117. 117. UltrawidebandResult The Future - New Technolgoies
  118. 118. UltrawidebandOne More Problem ♦ A single sine wave contains no information • Wheres the modulation? The Future - New Technolgoies
  119. 119. UltrawidebandWhat If The Future - New Technolgoies
  120. 120. MEMSMicroElectroMechanical Systems ♦ Semiconductors that can physically move • Superior electrical properties • Low cost manufacturing (in volume) The Future - New Technolgoies
  121. 121. Switch Comparison PIN Electromechanical MEMSInsertion loss 1 dB 0.1 dB 0.1 dBSwitching speed Microsec Millisec MicrosecSize Small Big TinyPower Moderate Substantial TinyPrice Low High Very low
  122. 122. BLASTBell Labs LAyered Space Time ♦ Dramatically increased data rate ♦ Send multiple signals over one frequency • Takes advantage of multipath ♦ More of a signal processing trick The Future - New Technolgoies
  123. 123. BLASTThe Future - New Technolgoies
  124. 124. BLASTThe Future - New Technolgoies
  125. 125. BLASTThe Future - New Technolgoies
  126. 126. BLASTThe Future - New Technolgoies
  127. 127. RFIDRadio Frequency IDentification ♦ Control, detect and track objects ♦ Uses unique numerical codes ♦ Not a new technology (1980s) ♦ Ubiquitous The Future - New Technolgoies
  128. 128. RFIDSystem ♦ Interrogator ♦ Transponder ("Tag") Interrogator Transponder Tx Tx Numerical code Rx Rx The Future - New Technolgoies
  129. 129. RFIDTypes Of Transponders ♦ Active • Onboard power source (i.e., battery) ♦ Passive • No onboard power source • Receives power from the transponder The Future - New Technolgoies
  130. 130. RFID Comparison Active PassiveTransponder Battery Interrogatorpower sourceInterrogator Low Highouptut powerRange 250 feet 1.5 feetFrequency ISM Low frequencyNumerical code Re-programmable Factory programmed
  131. 131. RFIDApplications ♦ Inventory tracking ♦ Toll road readers ♦ Cashless payments ♦ Electronic article surveillance The Future - New Technolgoies
  132. 132. TelematicsWhat ♦ Using position-locating technology for value- added automobile services • OnStar™ The Future - New Technologies
  133. 133. 4. The FutureNew TechnologiesSecurity IssuesHealth Concerns
  134. 134. Wireless SecurityUnique Challenges ♦ Mobile devices ♦ Limited computing power ♦ Limited bandwidth ♦ Interface weakness The Future - Security Issues
  135. 135. Wireless SecuritySome Solutions ♦ Point to point systems ♦ Encryption The Future - Security Issues
  136. 136. RecallPoint-To-Multipoint
  137. 137. A Better SolutionSmart Antennas The Future - Security Issues
  138. 138. EncryptionTwo Protocols ♦ Wired Equivalent Privacy (WEP) • For use with 802.11 networks • Weakness: Shared key ♦ Wireless Layer Transport Security (WLTS) • For use with WAP • Weakness: Wireless-wired interface The Future - Security Issues
  139. 139. EncryptionHow Is It Done ♦ Just like DSSS ♦ PN replaced by encryption key Data signalEncryption key The Future - Security Issues
  140. 140. 4. The FutureNew Technologies Security IssuesHealth Concerns
  141. 141. Health ConcernsStatus ♦ Evidence inconclusive ♦ Results statistical in nature The Future - Health Concerns
  142. 142. Adverse Health EffectsTwo 1) Ionization • Molecular changes 2) Thermal • Body heating The Future - Health Concerns
  143. 143. Health ConcernsRF Factors Effecting Heating ♦ Frequency • It depends ♦ Power density • High is bad ♦ Time of exposure • Long is bad The Future - Health Concerns
  144. 144. FrequencyBad Frequencies ♦ 30 -300 MHz • Most efficient absorption by body ♦ 2.4 GHz • Efficient absorption by water The Future - Health Concerns
  145. 145. Power DensityIn Perspective ♦ 100 mW/cm2 = microwave oven ♦ 1 mW/cm2 = measurable body heating ♦ 1 µW/cm2 = at the bottom of a cell tower The Future - Health Concerns
  146. 146. TimeKey Issue ♦ Can the body dissipate the heat • Depends on blood flow • Some areas more vulnerable than others The Future - Health Concerns
  147. 147. FCCExposure Guidelines ♦ Whole body • Power density (mW/cm2) • Averaged over 30 minutes ♦ Partial body • Specific absorption rate (W/Kg) • 1.6 W/Kg maximum The Future - Health Concerns
  148. 148. The Bottom LineYoure more likely to be injured in a car crash while youre talking onyour cell phone than youare from its RF radiation The Future - Health Concerns
  149. 149. The Future The end
  150. 150. Module 4 -Systems 2 The end Good

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