Introduction to RF & Wireless - Part 3

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Part 3 goes into details on legacy wireless systems and mobile telephony

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Introduction to RF & Wireless - Part 3

  1. 1. Why are 1988 pennies worth more than 1983 pennies?
  2. 2. Why are 1988 pennies worth more than 1983 pennies?
  3. 3. Introduction to RF & Wireless Two Day Seminar Module 3
  4. 4. Daily Schedule8:30 am – 10: 00 am Fun10:00 am – 10:15 am Break10:15 am – 11:45 am FunNoon – 1:00 pm Lunch1:00 pm – 2:30 pm Fun2:30 pm – 2:45 pm Break2:45 pm – 4:15 pm Fun
  5. 5. 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
  6. 6. Module 3 - Systems I 1. Older Systems 2. Mobile Telephony
  7. 7. Module 3 - Systems I 1. Older Systems 2. Mobile Telephony
  8. 8. 1. Older Systems Broadcasting Radar SatellitesPoint-To-Point Microwave
  9. 9. 1. Older Systems Broadcasting Radar SatellitesPoint-To-Point Microwave
  10. 10. BroadcastingAspects ♦ One way communication • Large geographical area • High power ♦ Frequency allocation • Bands • Channels Older Systems - Broadcasting
  11. 11. BroadcastingUS Band Allocations Older Systems - Broadcasting
  12. 12. BroadcastingUS Channel Allocations Service Channel Allocatiion AM Radio 10 KHz FM Radio 200 KHz Television 6 MHz Older Systems - Broadcasting
  13. 13. BroadcastingSignal ♦ Carrier • 181 MHz Carrier ♦ Information • 6 MHz Information
  14. 14. BroadcastingTuner From ♦ Part of the antenna receiver Tunable filter Tunable oscillator Older Systems - Broadcasting
  15. 15. BroadcastingBefore TheFilter Older Systems - Broadcasting
  16. 16. BroadcastingAfter TheFilter Older Systems - Broadcasting
  17. 17. BroadcastingAfter TheMixer ♦ Baseband 0-6 MHz Older Systems - Broadcasting
  18. 18. BroadcastingOne Problem ♦ Line of sight • Receiver must be able to "see" transmitter • Antenna may have to be readjusted • Tall buildings may cause ghosts • Earths curvature is a limitation Older Systems - Broadcasting
  19. 19. 1. Older Systems Broadcasting Radar SatellitesPoint-To-Point Microwave
  20. 20. RadarRAdio Detecting And Ranging ♦ Uses a reflected RF signal to determine • Distance • Direction • Velocity Older Systems - Radar
  21. 21. Types & Frequency Allocation Radar Band Frequency Uses UHF 200 MHz Early warning VHF 400 MHz Satellite L-band 1000 MHz Air traffic control S-band 2 GHz Shipboard C-band 5 GHz Altimeter X-band 10 GHz Weather, police Ku-band 14, 15 GHz Airborne fighter Older Systems - Radar
  22. 22. RadarHow It Determines Distance Distance = Velocity x Time Older Systems - Radar
  23. 23. RadarHow It Determines Direction Older Systems - Radar
  24. 24. RadarBeamwidthTradeoffs Older Systems - Radar
  25. 25. AtmosphericAttenuation
  26. 26. RadarMore Tradeoffs ♦ Power vs size Older Systems - Radar
  27. 27. RadarHow It Determines Velocity ♦ Doppler shift Frequency 1 Frequency 2 Older Systems - Radar
  28. 28. RadarApplications Altimeter Older Systems - Radar
  29. 29. Radar Applications Near Object AdaptiveDetection (NODS) Cruise Control Older Systems - Radar
  30. 30. 1. Older Systems Broadcasting Radar SatellitesPoint-To-Point Microwave
  31. 31. SatellitesWhy? ♦ Long range communications Uplink Downlink Older Systems - Satellites
  32. 32. SatellitesWhere ♦ Geosynchronous Orbit (GEO) • Approximately 22,000 miles up • Only at the equator Older Systems - Satellites
  33. 33. GEO Satellites Band Frequency AllocationC-band downlink 3.7 – 4.2 GHzC-band uplink 5.925 – 6.425 GHzKu-band downlink 11.7 – 12. 2 GHzKu-band uplink 14.0 – 14. 5 GHzKa-band downlink 27.5 –29.5 GHzKa-band uplink 29.5 – 31.0 GHz Older Systems - Satellites
  34. 34. GEO SatellitesFootprint ♦ "Antenna pattern" • CONUS Older Systems - Satellites
  35. 35. GEO Satellites3 Topologies ♦ Point to point • Telephony, backhaul Older Systems - Satellites
  36. 36. GEO Satellites3 Topologies ♦ Point to multipoint • Direct to home (DTH) TV Older Systems - Satellites
  37. 37. GEO Satellites3 Topologies ♦ Multipoint to point • VSAT Older Systems - Satellites
  38. 38. GEO SatellitesSpacecraft Hardware 1) Antennas 2) Transponders Older Systems - Satellites
  39. 39. GEO SatellitesSpacecraft Antennas ♦ Frequency vs size tradeoff • Ku-band must be CONUS Older Systems - Satellites
  40. 40. GEO SatellitesTransponders ♦ "Bent pipe" Older Systems - Satellites
  41. 41. SatellitesGround Hardware ♦ Dish antennas • "Funnel reflectors" Older Systems - Satellites
  42. 42. SatellitesDish Antennas ♦ Bigger the dish = higher the power • Transmitting • Receiving Older Systems - Satellites
  43. 43. SatellitesGPS ♦ Global Positioning System • Run by DOD • 24 satellites • Medium Earth Orbit (MEO) • Used to determine location Older Systems - Satellites
  44. 44. GPSHow It Works Distance = Velocity x Time Older Systems - Satellites
  45. 45. GPSHow It Works Older Systems - Satellites
  46. 46. GPSHow It Works Older Systems - Satellites
  47. 47. GPSHow It Works Older Systems - Satellites
  48. 48. GPSHow It Works Older Systems - Satellites
  49. 49. SatellitesLEO ♦ Low Earth Orbit • Low power • No time delay • Telephony • Internet Older Systems - Satellites
  50. 50. LEOHow It Works: Approach 1 Older Systems - Satellites
  51. 51. LEOHow It Works: Approach 1 Older Systems - Satellites
  52. 52. LEOHow It Works: Approach 1 Older Systems - Satellites
  53. 53. LEOHow It Works: Approach 2 Local Earth station Older Systems - Satellites
  54. 54. LEO Constellations System # Sats Principal StatusSkybridge 80 Alcatel DelayedGlobalstar 48 Loral WorkingTeledesic 288 Lockheed 2005Iridium 66 Motorola DeadICO Global 12* McCaw 2003 Older Systems - Satellites
  55. 55. SatellitesNext Generation ♦ GEO ♦ Two way ♦ Ka-band • Spot beams • Internet Older Systems - Satellites
  56. 56. SatellitesNext Generation ♦ Pluses • Internet + programming ♦ Minuses • Expensive satellites • Susceptible to rain fade • Time delay Older Systems - Satellites
  57. 57. Ka Band Satellites System Principal StatusSpaceway Hughes 2003Astrolink Lockheed 2003EuroSkyway Alenia (Italy) ??? Older Systems - Satellites
  58. 58. 1. Older Systems Broadcasting Radar SatellitesPoint-To-Point Microwave
  59. 59. Point To Point MicrowaveWhat ♦ Licensed frequency bands ♦ "Microwave relay" ♦ Uses directional "dish" antennas Older Systems - Point To Point Microwave
  60. 60. Point To Point MicrowaveUses ♦ Voice backhaul ♦ Video backhaulLimitations ♦ Line of sight ♦ Fresnel zones ♦ Multipath Older Systems - Point To Point Microwave
  61. 61. Fresnel ZonesWhat ♦ Elliptical areas ♦ Contain much of the RF energy ♦ Result of using dish antennas ♦ Size is a function of • Distance • Frequency Older Systems - Point To Point Microwave
  62. 62. Fresnel ZonesVisual Depiction RF energy Older Systems - Point To Point Microwave
  63. 63. Fresnel ZonesVisual Depiction Fresnel zone Distance Older Systems - Point To Point Microwave
  64. 64. Fresnel ZonesConsequences Older Systems - Point To Point Microwave
  65. 65. Fresnel ZonesCure ♦ High antennas Older Systems - Point To Point Microwave
  66. 66. MultipathWhat ♦ A result of reflection ♦ Transmitted signal can take multiple paths to receiver ♦ Signals may be out of phase Older Systems - Point To Point Microwave
  67. 67. MultipathVisual Depiction a th Refle cted p Direct path Older Systems - Point To Point Microwave
  68. 68. MultipathCure ♦ Signal processing ♦ Antenna diversity • Spatial diversity Older Systems - Point To Point Microwave
  69. 69. Diversity ReviewDifferent Kinds ♦ Frequency ♦ Antenna (spatial) ♦ Polarization ♦ Temporal (time) Older Systems - Point To Point Microwave
  70. 70. RecapBroadcasting Carrier frequency vs Information bandwidth frequency Radar Distance, direction, velocity Antenna size vs frequency Satellites Three topologies Three orbits: GEO, MEO, LEOPoint-to Point Fresnel zones Multipath Diversity
  71. 71. Older Systems The end
  72. 72. Module 3 - Systems I 1. Older Systems 2. Mobile Telephony
  73. 73. 2. Mobile TelephonyOverview Cellular SystemsAir Interfaces CDMA In DepthBlock Diagram The Future
  74. 74. 2. Mobile TelephonyOverview Cellular SystemsAir Interfaces CDMA In DepthBlock Diagram The Future
  75. 75. Current Worldwide SystemsUnited States ♦ AMPS, D-AMPS, SMR, CDMA, PCS • 800 MHz, 900 MHz, 1900 MHzEurope ♦ NMT, TACS, GSM, DCS • 450 MHz, 900 MHz, 1800 MHzJapan ♦ JTACS, PDC • 800 MHz, 1500 MHz
  76. 76. DifferentiatorsFrequency Bands ♦ Multiple bands ♦ Multiple providers per bandModulation Type ♦ Analog and digitalAir Interface ♦ Dividing up the bands Mobile Telephony - Overview
  77. 77. Generations1G 2G 2.5G 3G 4G Mobile Telephony - Overview
  78. 78. Future DifferentiatorsSwitching Type ♦ Circuit vs packetOfferings ♦ Voice through multimediaData Rate ♦ 14 Kbps to 2 Mbps Mobile Telephony - Overview
  79. 79. A Quick Comparison 1G 2G 2.5G 3GModulation Analog Digital Digital DigitalSwitching Circuit Circuit Circuit/Packet PacketOfferings Voice Messaging Internet MultimediaData Rate - 14 Kbps 144 Kbps 384 Kbs – 2 Mbps Mobile Telephony - Overview
  80. 80. 2. Mobile TelephonyOverview Cellular SystemsAir Interfaces CDMA In DepthBlock Diagram The Future
  81. 81. Cellular SystemsCellular Division ♦ Frequency ♦ Geography Mobile Telephony - Cellular Systems
  82. 82. Cellular SystemsUS Frequency Allocations Mobile Telephony - Cellular Systems
  83. 83. Cellular Systems"Full Duplex" Mobile Telephony - Cellular Systems
  84. 84. Cellular SystemsBand Allocations Mobile Telephony - Cellular Systems
  85. 85. Cellular SystemsBand Allocations Mobile Telephony - Cellular Systems
  86. 86. Band AllocationsUpstream
  87. 87. One Upstream BandProblem ♦ Too much bandwidth
  88. 88. One Upstream BandSolution ♦ Divide up the band • Frequency Division Multiple Access (FDMA) • An air Interface
  89. 89. One Upstream BandSolution ♦ Divide up the band • Frequency Division Multiple Access (FDMA) • An air Interface
  90. 90. Cellular Systems RuralGeography Statistical Area (RSA) MetropolitanStatistical Area (MSA) Mobile Telephony - Cellular Systems
  91. 91. Cellular SystemsTopology
  92. 92. Cellular SystemsCellStructure
  93. 93. Cellular SystemsCell StructureAntennapattern Mobile telephony - Cellular Systems
  94. 94. Cellular SystemsCell StructureAntennapattern Mobile telephony - Cellular Systems
  95. 95. Cellular SystemsTypical Sector 1AntennaPattern Sector 3 Sector 2 Mobile telephony - Cellular Systems
  96. 96. Recap CELLULAR DIVISIONFrequency Upstream & downstreamStreams Bands (different providers) Bands Individual calls (FDMA) U.S. MSAs & RSAs Areas Cells Cells Sectors
  97. 97. Cellular SystemsUnique Aspects 1) Frequency reuse 2) Mobility 3) Low power Mobile Telephony - Cellular Systems
  98. 98. Frequency ReuseWhat ♦ The ability to use the same frequency more than once, at the same time, in an MSA or RSA Mobile telephony - Cellular Systems
  99. 99. Frequency ReuseCell Spacing ♦ Depends on S/N ratio ♦ Varies from 4 to 21 Mobile telephony - Cellular Systems
  100. 100. MobilityWhat Is It ♦ The ability to change the receiver you communicate with as you move • Handoff Mobile Telephony - Cellular Systems
  101. 101. HandoffHow ♦ All basestations periodically transmit a pilot signal • Cell phone uses power discrimination Pilot Pilot Mobile Telephony - Cellular Systems
  102. 102. HandoffHow ♦ Cell phone requests handoff • Uses access signal Access Mobile Telephony - Cellular Systems
  103. 103. MobilityHandoff Mobile Telephony - Cellular Systems
  104. 104. MobilityHandoff Mobile Telephony - Cellular Systems
  105. 105. MobilityHandoffMaximum data rate depends on speed Mobile Telephony - Cellular Systems
  106. 106. Cellular SystemsInfrastructure ♦ Area ♦ Cell ♦ Transmitter/Receiver ♦ Adding capacity Mobile Telephony - Cellular Systems
  107. 107. AreaInfrastructure
  108. 108. Cell Infrastructure Sector antennas"Basestation" Equipment hut Telco Transmitter Receiver Controller Cable Power supply Batteries
  109. 109. Cell InfrastructureSpatial Diversity ♦ To overcome multipath Multiple receive antennas Mobile Telephony - Cellular Systems
  110. 110. Cell InfrastructureTransmitter ♦ Filter after the HPA Cavity filter Most transmitters Basestation transmitters Mobile Telephony - Cellular Systems
  111. 111. Cell InfrastructureReceiver ♦ Filter before the LNA Low-loss filter Most receivers Basestation receivers Mobile Telephony - Cellular Systems
  112. 112. Cell InfrastructureReceiver ♦ Filter after the LNA Cavity or Superconducting filter Cooled LNA Most receivers Basestation receivers Mobile Telephony - Cellular Systems
  113. 113. Cell InfrastructureAnother Issue Insertion Loss 5 dB? Telco Controller Power supply Batteries
  114. 114. Cell InfrastructureA Solution Tower Top System Telco Controller Power supply Batteries
  115. 115. Cellular SystemsAdding Capacity 1) Within a cell 2) Areas without coverage in an MSA or RSA Mobile Telephony - Cellular Systems
  116. 116. Adding CapacityWithin AMacrocell Mobile Telephony - Cellular Systems
  117. 117. Adding CapacityMicrocellsPicocells Mobile Telephony - Cellular Systems
  118. 118. Adding CapacityAreas Without Coverage ♦ In buildings ♦ In tunnels ♦ Obstructed areas ♦ Fringe areas ♦ Dead spots Mobile Telephony - Cellular Systems
  119. 119. Adding CapacityUse Repeaters Repeater Macrocell Mobile Telephony - Cellular Systems
  120. 120. Adding CapacityDead Spots Mobile telephony - Cellular Systems
  121. 121. Adding Capacity1. Repeaters More cells or repeaters Mobile telephony - Cellular Systems
  122. 122. Adding CapacityDead Spots Mobile telephony - Cellular Systems
  123. 123. Adding Capacity2. Superconducting Filters Mobile telephony - Cellular Systems
  124. 124. Adding CapacityDead Spots Mobile telephony - Cellular Systems
  125. 125. Adding Capacity3. Smart Antennas Mobile telephony - Cellular Systems
  126. 126. 2. Mobile TelephonyOverview Cellular SystemsAir Interfaces CDMA In DepthBlock Diagram The Future
  127. 127. Air InterfacesFive ♦ FDMA ♦ TDMA ♦ CDMA ♦ SDMA ♦ CDPD Mobile Telephony - Air Interfaces
  128. 128. FDMAFrequency DivisionMultiple Access
  129. 129. FDMAMobile Telephony - Air Interfaces
  130. 130. TDMATime Division Multiple Access ♦ Each frequency is divided into time slots • 3 - 6 different time slots • Uses buffering Mobile Telephony - Aire Interfaces
  131. 131. TDMA + FDMA
  132. 132. CDMACode Division Multiple Access ♦ Conversations share frequencies & are distinguished by their "address" Mobile Telephony - Air Interfaces
  133. 133. CDMA ♦ The envelope gets addressed
  134. 134. CDMA ♦ The envelope gets addressed
  135. 135. CDMA
  136. 136. CDMA + FDMA
  137. 137. SDMASpatial Division Multiple Access ♦ Subdividing cell sectors into subsectors ♦ Uses smart antennas Mobile Telephony - Air Interfaces
  138. 138. SDMASmartAntennaPattern Mobile telephony - Air Interfaces
  139. 139. CDPDCellular Digital Packet Data ♦ Used for data only (no voice) ♦ Uses unused frequencies and unused time slots Mobile Telephony - Air Interfaces
  140. 140. RecapFDMA Divides a frequency band into sub-bandsTDMA Divides a sub-band into time slotsCDMA Overlapping conversations, unique addressesSDMA Divides an antenna sector into subsectorsCDPD Uses unused frequencies & time slots (data only)
  141. 141. 2. Mobile TelephonyOverview Cellular SystemsAir Interfaces CDMA In DepthBlock Diagram The Future
  142. 142. Noise Spectrum Signal Spectrum
  143. 143. CDMAWhat ♦ Takes the energy contained in a narrowband signal and spreads it over a larger bandwidth • Spread spectrum ♦ As a consequence, the power level drops • It appears to be noise Mobile Telephony - CDMA
  144. 144. CDMAVisually Narrowband signal Mobile Telephony - CDMA
  145. 145. CDMAVisually Spread signal Mobile Telephony - CDMA
  146. 146. CDMAGraphically Mobile Telephony - CDMA
  147. 147. CDMAGraphically Spectral density is constant Mobile Telephony - CDMA
  148. 148. CDMAWhy Spread ♦ Spread signals drop down into the noise ♦ Noise is noise ♦ Up to a point, noise signals can be piled on top of each other without effecting anything Mobile Telephony - CDMA
  149. 149. SpreadingWhere Does Spreading Occur Mobile Telephony - CDMA
  150. 150. CDMAWhat Is Spreading ♦ Another modulation • Much higher frequency • Chipping rate Data signal XORSpreading signal Mobile Telephony - CDMA
  151. 151. CDMAThis Kind Of Spreading ♦ Direct sequence spread spectrum (DSSS) XOR Mobile Telephony - CDMA
  152. 152. CDMASpreading Signal ♦ Spreading signal is a pseudo random Noise (PN) signal • Random • Pseudo ♦ Every user has their own unique PN signal Mobile Telephony - CDMA
  153. 153. CDMASpreading Example Mobile Telephony - CDMA
  154. 154. De-SpreadingWhere Does De-Spreading Occur Mobile Telephony - CDMA
  155. 155. CDMADe-Spreading Example Mobile Telephony - CDMA
  156. 156. CDMAReceiving Someone Elses Signal Mobile Telephony - CDMA
  157. 157. CDMAPN Signals ♦ One continuous looping signal • Everyone uses the same looping signal, BUT • They start at a different point in the loop ♦ Must be synchronized • Basestation to cell phone • Basestation to basestation Mobile Telephony - CDMA
  158. 158. PN SynchronizationHow GPS Voice + Synch + Pilot Mobile Telephony - CDMA
  159. 159. 2. Mobile TelephonyOverview Cellular SystemsAir Interfaces CDMA In DepthBlock Diagram The Future
  160. 160. Block Diagram Mobile Telephony - Block Diagram
  161. 161. 2. Mobile TelephonyOverview Cellular SystemsAir Interfaces CDMA In DepthBlock Diagram The Future
  162. 162. The FutureVision For 3G ♦ Global standard ♦ One frequency ♦ Pure packet-based networks ♦ Bandwidth on demand (up to 2 Mbps) • IMT-2000 Mobile Telephony - The Future
  163. 163. Roadmap To 3G AT&T Cingular Verizon Sprint
  164. 164. The FutureProblems On The Road To 3G ♦ No global standard ♦ Multiple frequencies ♦ Ground up vs upgrade ♦ Real world vs the lab ♦ How to make money Mobile Telephony - The Future
  165. 165. The Future3G To Date ♦ 3G services vs 3G networks ♦ Asia • i-Mode in Japan ♦ Europe • Under construction ♦ US • 2003-2007 Mobile Telephony - The Future
  166. 166. The FutureWhat About 4G ♦ Improved modulation ♦ Smart antennas ♦ >2 Mbps ♦ Video on demand ♦ Pure IP ♦ 2006 - 2010 Mobile Telephony - The Future
  167. 167. Mobile Telephony The end
  168. 168. Module 3 - Systems I The end

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