Introduction to RF & Wireless - Part 4
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Introduction to RF & Wireless - Part 4

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

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

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Introduction to RF & Wireless - Part 4 Presentation Transcript

  • 1. Introduction to RF & Wireless Two Day Seminar Module 4
  • 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. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  • 4. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  • 5. 1. Broadband Fixed Wireless ChoicesAir Link Transmission Technologies
  • 6. 1. Broadband Fixed Wireless ChoicesAir Link Transmission Technologies
  • 7. Local Loop Wireless local loopTelephone Cablelocal loop local loop Broadband Fixed Wireless - Choices
  • 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. ConfigurationsPoint-To-Point Broadband Fixed Wireless - Choices
  • 10. ConfigurationsPoint-To-Multipoint Broadband Fixed Wireless - Choices
  • 11. ChoicesBroadband Fixed Wireless ♦ MMDS ♦ LMDS ♦ Unlicensed ♦ Wireless fiber Broadband Fixed Wireless - Choices
  • 12. MMDSMultichannel MultipointDistribution Service ♦ Licensed ♦ 2.6 GHz ♦ 2 Mbps ♦ Point-to-multipoint ♦ 35 miles Broadband Fixed Wireless - Choices
  • 13. LMDSLocal MultipointDistribution Service ♦ Licensed ♦ 31GHz ♦ 155 Mbps ♦ Point-to-point ♦ 3 miles Broadband Fixed Wireless - Choices
  • 14. AtmosphericAttenuation
  • 15. UnlicensedUnlicensed Spread Spectrum ♦ No license required ♦ ISM frequency bands ♦ ??? Mbps ♦ Point-to-point and point-to-multipoint ♦ ??? miles Broadband Fixed Wireless - Choices
  • 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. 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. UnlicensedTypicalDeployment t Pt to P H z 5 .8G Pt to Multipoint 2.4 GHz ISP Broadband Fixed Wireless - Choices
  • 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. Wireless FiberFree Space Optics ♦ Unlicensed ♦ Infrared frequency ♦ 622 Mbps ♦ Point to point ♦ Less than 1 mile Broadband Fixed Wireless - Choices
  • 21. Wireless Fiber Transceiver Broadband Fixed Wireless - Choices
  • 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. 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. 1. Broadband Fixed Wireless ChoicesAir Link Transmission Technologies
  • 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. Two Way CommunicationsSimplex ♦ One frequency ♦ One party transmits at a time • Walkie-talkies Frequency 1 Frequency 1 Braodband Fixed Wireless - Air Link Transmissi
  • 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. 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. 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. FDDFrequency Division Duplexing ♦ Dividing the allotted frequency into sub-bands ♦ Each sub-band has a designated direction Braodband Fixed Wireless - Air Link Transmissi
  • 31. FDD ISM bandBraodband Fixed Wireless - Air Link Transmissi
  • 32. FDDBraodband Fixed Wireless - Air Link Transmissi
  • 33. FDD + FDMA Braodband Fixed Wireless - Air Link Transmissi
  • 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. TDD ISM bandBraodband Fixed Wireless - Air Link Transmissi
  • 36. TDDBraodband Fixed Wireless - Air Link Transmissi
  • 37. Multipath Is A Problem a th Refle cted p Direct path Braodband Fixed Wireless - Air Link Transmissi
  • 38. So Is Line Of Sight a th Refle cted p Direct path
  • 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. OFDMVisually Braodband Fixed Wireless - Air Link Transmissi
  • 41. OFDM Example
  • 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. Broadband Fixed Wireless The end
  • 44. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  • 45. 2. Wireless Networks Local Area Networks Personal Area Networks Home Networks
  • 46. 2. Wireless NetworksLocal Area Networks Personal Area Networks Home Networks
  • 47. Local Area Networks (LAN)Parameters ♦ Limited area • Floor or campus ♦ Some mobility • Walking around ♦ Server centric Wireless Networks - Local Area Networks
  • 48. Basic Architecture Wireless Networks - Local Area Networks
  • 49. Basic ArchitectureBasic Service Set BSS Wireless Networks - Local Area Networks
  • 50. Basic Architecture BSS BSSExtended Service Set Wireless Networks - Local Area Networks
  • 51. Access Point Wireless Networks - Local Area Networks
  • 52. Local Area NetworksFrequency ♦ Unlicensed bands • ISM bandsAir Interface ♦ Mostly Spread spectrum • Direct sequence • Frequency hopping Wireless Networks - Local Area Networks
  • 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. FHSSWireless Networks - Local Area Networks
  • 55. FHSSWireless Networks - Local Area Networks
  • 56. FHSSWireless Networks - Local Area Networks
  • 57. FHSSWireless Networks - Local Area Networks
  • 58. FHSSWireless Networks - Local Area Networks
  • 59. FHSSWireless Networks - Local Area Networks
  • 60. FHSSWireless Networks - Local Area Networks
  • 61. FHSSWireless Networks - Local Area Networks
  • 62. FHSSWireless Networks - Local Area Networks
  • 63. FHSSWireless Networks - Local Area Networks
  • 64. FHSSHow Wireless Networks - Local Area Networks
  • 65. FHSSHow Wireless Networks - Local Area Networks
  • 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. Choices802.11 ♦ Originated in the US ♦ Based in Ethernet ♦ Shared frequencyHiperLAN ♦ Originated in Europe ♦ Based in GSM ♦ Unique frequency
  • 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. 2. Wireless Networks Local Area NetworksPersonal Area Networks Home Networks
  • 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. Personal Area NetworksRequirements ♦ Interoperability • Mobiles talking to mobiles ♦ Short range • Low power/low interference ♦ Self discovery • Auto initiate Wireless Networks - Personal Area Networks
  • 72. Personal Area NetworksApplications ♦ Impromptu networks Piconet Wireless Networks - Personal Area Networks
  • 73. Personal Area NetworksApplications ♦ Cell phone as wireless modem Wireless Networks - Personal Area Networks
  • 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. BluetoothParameter SpecificationData Rate 1 Mbps Range 30 feetFrequency 2.4 GHzTechnology FHSS Wireless Networks - Personal Area Networks
  • 76. 2.4 GHz ReduxWho Uses 2.4 GHz ♦ Microwave ovens ♦ Cordless phones ♦ Broadband fixed wireless providers ♦ Wireless networks ♦ Bluetooth networks
  • 77. 2. Wireless Networks Local Area Networks Personal Area Networks Home Networks
  • 78. Home NetworksTwo Systems ♦ HomeRF • For the home ♦ IrDA • For the home and the office Wireless Networks - Home Networks
  • 79. HomeRFParameters ♦ Limited area • The home ♦ Some mobility • Within the home ♦ Home centric • Information appliances Wireless Networks - Home Networks
  • 80. HomeRFRequirements ♦ Low cost • Consumer market ♦ Versatile • Data, voice, audio, video ♦ Interoperability • 802.11 + DECT Wireless Networks - Home Networks
  • 81. HomeRF Vision
  • 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. IrDaDescription ♦ An industry standard • For data only • Uses infrared light • Good for about 3 feet ♦ Embedded in most gadgets Wireless Networks - Home Networks
  • 84. IrDAApplications ♦ Wireless synching Wireless Networks - Personal Area Networks
  • 85. IrDAApplications ♦ Upload digital photos Wireless Networks - Personal Area Networks
  • 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. Recap Area Mobility CenterLAN Floor Walking ServerPAN Everywhere Walking PersonHome RF Home Walking HomeIrDA Few feet None Decentralized
  • 88. Wireless Networks The end
  • 89. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  • 90. Mobile Internet Wireless Internet
  • 91. Mobile InternetDefined ♦ Mobile devices • Cell phones, PDAs, laptops ♦ Wide area • City, state, country ♦ High mobility • Driving around speed Mobile Internet - Technology
  • 92. Mobile InternetChallenges ♦ Data rate • Depends on the device ♦ Screen size • Different content ♦ Ubiquity • I want it everywhere Mobile Internet - Technology
  • 93. Mobile Internet Candidates Cellular ISM LEOs Mobile Internet - Technology
  • 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. Mobile InternetInfrastructure Changes ♦ Wireless portion ♦ Internet portion Mobile Internet - Technology
  • 96. Mobile InternetWireless Infrastructure Changes ♦ Mobile switching center • Gateway for separating voice from data • Packet switching ♦ Mobile device • Microbrowser Mobile Internet - Technology
  • 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. 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. Mobile InternetVisually
  • 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. 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. WAPVisually WAP WAP Server
  • 103. WAPWorks ♦ Over all technologies • Mobile telephony • Bluetooth ♦ Over all frequencies • Cellular • PCS • ISM Mobile Internet - WAP
  • 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. M-CommercePossibilities ♦ Comparison shopping ♦ Location-specific services ♦ Advertising ♦ Financial transactions ♦ Entertainment Mobile Internet - M-Commerce
  • 106. Mobile InternetStatus ♦ Cellular • i-Mode in Japan ♦ ISM • Ricochet died ♦ LEOs • Stay tuned Mobile Internet - Status
  • 107. Mobile Internet The end
  • 108. Module 4 - Systems 21. Broadband Fixed Wireless 2. Wireless Networks 3. Mobile Internet 4. The Future
  • 109. 4. The FutureNew Technologies Security IssuesHealth Concerns
  • 110. 4. The FutureNew Technologies Security Issues Health Concerns
  • 111. New TechnologiesFive 1) Ultrawideband 2) MEMS 3) BLAST 4) RFID 5) Telematics The Future - New Technolgoies
  • 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. UltrawidebandVisually Monocycles The Future - New Technolgoies
  • 114. UltrawidebandProblem Same frequency The Future - New Technolgoies
  • 115. UltrawidebandResult The Future - New Technolgoies
  • 116. UltrawidebandWhat If Time hopping spread spectrum The Future - New Technolgoies
  • 117. UltrawidebandResult The Future - New Technolgoies
  • 118. UltrawidebandOne More Problem ♦ A single sine wave contains no information • Wheres the modulation? The Future - New Technolgoies
  • 119. UltrawidebandWhat If The Future - New Technolgoies
  • 120. MEMSMicroElectroMechanical Systems ♦ Semiconductors that can physically move • Superior electrical properties • Low cost manufacturing (in volume) The Future - New Technolgoies
  • 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. 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. BLASTThe Future - New Technolgoies
  • 124. BLASTThe Future - New Technolgoies
  • 125. BLASTThe Future - New Technolgoies
  • 126. BLASTThe Future - New Technolgoies
  • 127. RFIDRadio Frequency IDentification ♦ Control, detect and track objects ♦ Uses unique numerical codes ♦ Not a new technology (1980s) ♦ Ubiquitous The Future - New Technolgoies
  • 128. RFIDSystem ♦ Interrogator ♦ Transponder ("Tag") Interrogator Transponder Tx Tx Numerical code Rx Rx The Future - New Technolgoies
  • 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. RFID Comparison Active PassiveTransponder Battery Interrogatorpower sourceInterrogator Low Highouptut powerRange 250 feet 1.5 feetFrequency ISM Low frequencyNumerical code Re-programmable Factory programmed
  • 131. RFIDApplications ♦ Inventory tracking ♦ Toll road readers ♦ Cashless payments ♦ Electronic article surveillance The Future - New Technolgoies
  • 132. TelematicsWhat ♦ Using position-locating technology for value- added automobile services • OnStar™ The Future - New Technologies
  • 133. 4. The FutureNew TechnologiesSecurity IssuesHealth Concerns
  • 134. Wireless SecurityUnique Challenges ♦ Mobile devices ♦ Limited computing power ♦ Limited bandwidth ♦ Interface weakness The Future - Security Issues
  • 135. Wireless SecuritySome Solutions ♦ Point to point systems ♦ Encryption The Future - Security Issues
  • 136. RecallPoint-To-Multipoint
  • 137. A Better SolutionSmart Antennas The Future - Security Issues
  • 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. EncryptionHow Is It Done ♦ Just like DSSS ♦ PN replaced by encryption key Data signalEncryption key The Future - Security Issues
  • 140. 4. The FutureNew Technologies Security IssuesHealth Concerns
  • 141. Health ConcernsStatus ♦ Evidence inconclusive ♦ Results statistical in nature The Future - Health Concerns
  • 142. Adverse Health EffectsTwo 1) Ionization • Molecular changes 2) Thermal • Body heating The Future - Health Concerns
  • 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. FrequencyBad Frequencies ♦ 30 -300 MHz • Most efficient absorption by body ♦ 2.4 GHz • Efficient absorption by water The Future - Health Concerns
  • 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. TimeKey Issue ♦ Can the body dissipate the heat • Depends on blood flow • Some areas more vulnerable than others The Future - Health Concerns
  • 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. 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. The Future The end
  • 150. Module 4 -Systems 2 The end Good