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Wireless commonsense fontsfixed

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  • 1. Wireless Common SenseShifting the Collection of Prejudices Robert J. Berger Internet Bandwidth Development Consulting rberger@ibd.com 1
  • 2. 2
  • 3. Common sense is the collection ofprejudices acquired by age eighteen - Albert Einstein 2
  • 4. Tech You Grew Up withShapes your Prejudices ofWireless Tech Capabilities 3
  • 5. Tech You Grew Up withShapes your Prejudices ofWireless Tech Capabilities 3
  • 6. Claude Shannon’s Communications TheoryShows us the Realitybeyond our prejudices 4
  • 7. C=W log (1+S/N) 5
  • 8. Shannon’s Theory C=W log (1+S/N)where; C=channel capacity (bits/second) 5
  • 9. Shannon’s Theory C=W log (1+S/N) where; C=channel capacity (bits/second)W=Bandwidth (How much Spectrum we are using) 5
  • 10. Shannon’s Theory C=W log (1+S/N) where; C=channel capacity (bits/second)W=Bandwidth (How much Spectrum we are using) S=signal power, and N=noise power 5
  • 11. Propagation Characteristics & Path Loss 6
  • 12. Propagation Characteristics & Path Loss• Determines how much of the signal power gets to the receiver 6
  • 13. Propagation Characteristics & Path Loss• Determines how much of the signal power gets to the receiver• The higher the frequency - the less easily the signal propagates 6
  • 14. Propagation Characteristics & Path Loss• Determines how much of the signal power gets to the receiver• The higher the frequency - the less easily the signal propagates 6
  • 15. Propagation Characteristics & Path Loss• Determines how much of the signal power gets to the receiver• The higher the frequency - the less easily the signal propagates - The more buildings, trees, hills the more attenuation 6
  • 16. Propagation Characteristics & Path Loss• Determines how much of the signal power gets to the receiver• The higher the frequency - the less easily the signal propagates - The more buildings, trees, hills the more attenuation• Physical Reality is such a Drag!! 6
  • 17. Radio & TV: Broadcast HIGH POWER & low frequency 7
  • 18. Radio & TV: Broadcast HIGH POWER & low frequency MEGA WATTS of Power!!! 7
  • 19. Radio & TV: Broadcast HIGH POWER & low frequency MEGA WATTS of Power!!! Spectrum in the 80 - 800 MHz range 7
  • 20. Radio & TV: Broadcast HIGH POWER & low frequency MEGA WATTS of Power!!! Spectrum in the 80 - 800 MHz range 50Khz - 6Mhz Channel Bandwidth 7
  • 21. Radio & TV: Broadcast HIGH POWER & low frequency MEGA WATTS of Power!!! Spectrum in the 80 - 800 MHz range 50Khz - 6Mhz Channel BandwidthGets Large Channel Capacity via Power and Significant Spectrum 7
  • 22. Tech from the 1930’sVery simple analog modulation Uses spectrum inefficiently Receiver has difficulty rejecting noise 8
  • 23. Cell Phones: Tiny Channel Capacity 9
  • 24. Cell Phones: Tiny Channel Capacity Low Signal Power & Advanced Modulation 9
  • 25. Cell Phones: Tiny Channel Capacity Low Signal Power & Advanced Modulation 800 - 1900Mhz a bit more difficult propagation, but still good 9
  • 26. Cell Phones: Tiny Channel Capacity Low Signal Power & Advanced Modulation 800 - 1900Mhz a bit more difficult propagation, but still good But only requires 4kbps Channel Capacity 9
  • 27. Cell Phones: Tiny Channel Capacity Low Signal Power & Advanced Modulation 800 - 1900Mhz a bit more difficult propagation, but still good But only requires 4kbps Channel Capacity High speed data phones will have less coverage or need more basestations 9
  • 28. Past Experience Does Not Apply to WiFi 10
  • 29. Past Experience Does Not Apply to WiFi Uses Unlicensed Spectrum 2.4Ghz & 5 - 6Ghz, Very Low Power 10
  • 30. Past Experience Does Not Apply to WiFi Uses Unlicensed Spectrum 2.4Ghz & 5 - 6Ghz, Very Low Power Rapid comidification & evolution - Very low cost & advanced modulation 10
  • 31. Past Experience Does Not Apply to WiFi Uses Unlicensed Spectrum 2.4Ghz & 5 - 6Ghz, Very Low Power Rapid comidification & evolution - Very low cost & advanced modulation Developed “Bottoms Up” like the Internet, not from Carriers or Broadcasters 10
  • 32. Unlicensed Wireless Constraints 11
  • 33. Unlicensed Wireless ConstraintsOriginal Spectrum considered “Junk Spectrum” 2.4Ghz is absorption frequency of water 5 - 6 Ghz propagates about 1/2 as well 11
  • 34. Unlicensed Wireless ConstraintsOriginal Spectrum considered “Junk Spectrum” 2.4Ghz is absorption frequency of water 5 - 6 Ghz propagates about 1/2 as well Can’t interfere, but must accept interference 11
  • 35. Unlicensed Wireless ConstraintsOriginal Spectrum considered “Junk Spectrum” 2.4Ghz is absorption frequency of water 5 - 6 Ghz propagates about 1/2 as well Can’t interfere, but must accept interference Very low power, but lots of spectrum 11
  • 36. Unlicensed Wireless ConstraintsOriginal Spectrum considered “Junk Spectrum” 2.4Ghz is absorption frequency of water 5 - 6 Ghz propagates about 1/2 as well Can’t interfere, but must accept interference Very low power, but lots of spectrum Very short distance with high bandwidth 11
  • 37. Average WiFi Link Budget 12
  • 38. Average WiFi Link Budget AP to Client limited by weakest link Avg clients’ Signal Power: 15dBm Avg AP Sensitivity 1Mbps: -94dBm 12
  • 39. Average WiFi Link Budget AP to Client limited by weakest link Avg clients’ Signal Power: 15dBm Avg AP Sensitivity 1Mbps: -94dBm Link Budget avg client to AP:signal power + xmit antenna gain - free space path loss + receiv antenna gain - receive sensitivity = Margin 12
  • 40. Average WiFi Link Budget AP to Client limited by weakest link Avg clients’ Signal Power: 15dBm Avg AP Sensitivity 1Mbps: -94dBm Link Budget avg client to AP:signal power + xmit antenna gain - free space path loss + receiv antenna gain - receive sensitivity = Margin 15dBm + 2dB - (-84) + 7dB - (-94dBM) = 34 dBm Margin at 150 Meters 12
  • 41. Link Margin 1 Mbps 11 Mbps 51 Link Margin 45 42 40 39 37 35 34 31 28 26 24 0 5 0 75 50 25 15 12 10 Meters 13
  • 42. Link MarginThe Free Space Loss 1 Mbps 11 Mbpscalculations areoptimistic 51 Link Margin 45 42 40 39 37 35 34 31 28 26 24 0 5 0 75 50 25 15 12 10 Meters 13
  • 43. Link MarginThe Free Space Loss 1 Mbps 11 Mbpscalculations areoptimistic 51 Link Margin 45Realistic distance of 39 42 40 37a laptop to an AP is 35 31 34~30m in the open 24 26 28 0 5 0 75 50 25 15 12 10 Meters 13
  • 44. Link MarginThe Free Space Loss 1 Mbps 11 Mbpscalculations areoptimistic 51 Link Margin 45Realistic distance of 39 42 40 37a laptop to an AP is 35 31 34~30m in the open 24 26 28At 150 Meters, Onegood tree will knockout your link 0 5 0 75 50 25 15 12 10 Meters 13
  • 45. Real World Constraints 14
  • 46. Real World Constraints WiFi originally designed for indoor LAN 14
  • 47. Real World Constraints WiFi originally designed for indoor LANWiFi CSMA does not handle large numbers of clients accessing an AP 14
  • 48. Real World Constraints WiFi originally designed for indoor LANWiFi CSMA does not handle large numbers of clients accessing an APNearby clients and APs not associated to an SSID can cause contention 14
  • 49. Real World Constraints WiFi originally designed for indoor LANWiFi CSMA does not handle large numbers of clients accessing an AP Nearby clients and APs not associated to an SSID can cause contentionAsymmetrical Power causes client misbehavior 14
  • 50. Real World Constraints WiFi originally designed for indoor LANWiFi CSMA does not handle large numbers of clients accessing an AP Nearby clients and APs not associated to an SSID can cause contentionAsymmetrical Power causes client misbehavior Obstructions: One Tree: 20dB One Wall: 10dB 14
  • 51. WiFi has to EvolveAround Limitations 15
  • 52. WiFi has to Evolve Around Limitations802.11 Phy has already evolved from 1Mbps to 802.11n with 125Mpbs 15
  • 53. WiFi has to Evolve Around Limitations802.11 Phy has already evolved from 1Mbps to 802.11n with 125Mpbs Distance not really improved (but more bandwidth for same short distance) 15
  • 54. WiFi has to Evolve Around Limitations802.11 Phy has already evolved from 1Mbps to 802.11n with 125Mpbs Distance not really improved (but more bandwidth for same short distance)Contention by nearby nodes not addressed yet (802.11s may, Proprietary extensions today) 15
  • 55. WiFi RecapitulatesEthernet Evolution 16
  • 56. WiFi RecapitulatesEthernet Evolution Originally Considered a “Toy” 16
  • 57. WiFi RecapitulatesEthernet Evolution Originally Considered a “Toy”Started out as LAN evolved to MAN 16
  • 58. WiFi Recapitulates Ethernet Evolution Originally Considered a “Toy” Started out as LAN evolved to MAN“Good Enough” and much less expensive 16
  • 59. WiFi Recapitulates Ethernet Evolution Originally Considered a “Toy” Started out as LAN evolved to MAN“Good Enough” and much less expensive Designed by NetHeads, not BellHeads 16
  • 60. WiFi Recapitulates Ethernet Evolution Originally Considered a “Toy” Started out as LAN evolved to MAN “Good Enough” and much less expensive Designed by NetHeads, not BellHeads Continually pushed beyond originallimitations, first by proprietary extensions, that migrate to standards 16
  • 61. WiFi RecapitulatesEthernet Evolution Still at the Hub & BridgeStage Compared toEthernet Evolution 16
  • 62. Mesh: Ideal Architecture for Unlicensed Bands 17
  • 63. Mesh: Ideal Architecture for Unlicensed Bands• Take advantage of 17
  • 64. Mesh: Ideal Architecture for Unlicensed Bands• Take advantage of - Limited range 51 45 42 40 39 35 37 34 31 28 24 26 0 5 0 75 50 25 15 12 10 17
  • 65. Mesh: Ideal Architecture for Unlicensed Bands• Take advantage of - Limited range - Low Cost components 17
  • 66. Mesh: Ideal Architecture for Unlicensed Bands• Take advantage of - Limited range - Low Cost components - Good amount of Spectrum 17
  • 67. Mesh: Ideal Architecture for Unlicensed Bands• Take advantage of - Limited range - Low Cost components - Good amount of Spectrum - Millions of Nodes 17
  • 68. Not Yet Near the Ideal 18
  • 69. Not Yet Near the IdealSome use 2.4Ghz forbackhaul & access! 18
  • 70. Not Yet Near the IdealSome use 2.4Ghz forbackhaul & access!Uses standard 802.11CSMA protocol 18
  • 71. Not Yet Near the IdealSome use 2.4Ghz forbackhaul & access!Uses standard 802.11CSMA protocolGives great demo: Worksgreat unloaded 18
  • 72. Not Yet Near the IdealSome use 2.4Ghz forbackhaul & access!Uses standard 802.11CSMA protocolGives great demo: Worksgreat unloadedAs usage grows,contention is multiplied& becomes unusable 18
  • 73. Not Yet Near the IdealSome use 2.4Ghz forbackhaul & access!Uses standard 802.11CSMA protocolGives great demo: Worksgreat unloadedAs usage grows,contention is multiplied& becomes unusable 18
  • 74. Today’s Best Practices for Mesh 19
  • 75. Today’s Best Practices for MeshUse different bands for Mesh& Access 19
  • 76. Today’s Best Practices for MeshUse different bands for Mesh& AccessCoordinate transmissions &directional antennas 19
  • 77. multi-node and DELIVERS INDUSTRYÊÂS HIGHEST THROUGHPUT, hitecture. LOWEST LATENCY ACROSS MULTIPLE HOPSh throughput ess hops. Today’s Best Practices for The award winning Access/One® Outdoor Wireless System (OWS) 3600 is the industry’s highest highest throughput, lowest latency modular multi-radio meshnode Mesh networking system. Utilizing Strix DMATM, the Access/One OWS delivers multi- radio, multi-RF and multi-channel capabilities using advanced algorithms to deliver high throughput over multiple hops from the core to the edge of the network.ver and self- Use different bandsself-tunes, self-configures and The OWS intelligently for Meshhealing mesh & Access to optimize the overall performance and self-heals availability. The OWS architecture makes 802.11 a full tion. duplex technology, moving traffic more efficientlywith voice, tization. Coordinate the network and utilizing different RF through transmissions & radio. directional antennas for network connectivity and frequencies and channels client access. RF Channels are selected dynamically,network and making the network more resilient to interference than tagging, with standard mesh networks. Working closely together, parameters Multiple Mesh Radios pluses these features deliver higher throughput and lower and minuses multiple hops, supporting real time latency acrossor roaming, failover. voice, video, and data applications. The OWS scales interface efficientlyof intuitive OWS is the most secure mesh and econ- the network, networking systemavailable, with omically s. the tools to authenticate users, minimizing the number of wired encrypt wireless traffic, and anagement monitor network activity all termination points required in the P, CLI over provided as standard features. network, greatly reduces deployment/HTTPS, Secure private networks can and operating costs and the Total Cost operate in tandem with open of Ownership (TCO). Extended 19
  • 78. Today’s Best Practices for MeshUse different bands for Mesh& AccessCoordinate transmissions &directional antennasMultiple Mesh Radios plusesand minusesMultiple tiers of Wirelessbackhaul 19
  • 79. Today’s Best Practices for MeshUse different bands for Mesh& AccessCoordinate transmissions &directional antennasMultiple Mesh Radios plusesand minusesMultiple tiers of WirelessbackhaulExpect < 1Mbps delivered 19
  • 80. State of Muni-Wireless (US Centric View) 20
  • 81. State of Muni-Wireless (US Centric View) 20
  • 82. State of Muni-Wireless (US Centric View) First phase build-outs 20
  • 83. State of Muni-Wireless (US Centric View) First phase build-outs Significant Learning Curve 20
  • 84. State of Muni-Wireless (US Centric View) First phase build-outs Significant Learning Curve First Generation Equipment 20
  • 85. State of Muni-Wireless (US Centric View) First phase build-outs Significant Learning Curve First Generation Equipment Be prepared for negative Hype Cycle People’s expectations too high 20
  • 86. State of Muni-Wireless (US Centric View) First phase build-outs Significant Learning Curve First Generation Equipment Be prepared for negative Hype Cycle People’s expectations too high Its still very early 20
  • 87. WiMax? 21
  • 88. WiMax? If WiFi recapitulates the evolution of Ethernet; WiMax recapitulates theevolution of all of Ethernet’s competitors 21
  • 89. WiMax? 22
  • 90. WiMax?No real advantage when comparing unlicensed WiMax & WiFi 22
  • 91. WiMax?No real advantage when comparing unlicensed WiMax & WiFi Licensed WiMax can be useful (ATM was useful for some things too) 22
  • 92. WiMax?No real advantage when comparing unlicensed WiMax & WiFi Licensed WiMax can be useful (ATM was useful for some things too)Getting a License can be difficult & Expensive 22
  • 93. WiMax?No real advantage when comparing unlicensed WiMax & WiFi Licensed WiMax can be useful (ATM was useful for some things too)Getting a License can be difficult & Expensive Very good for feeding WiFi Mesh 22
  • 94. WiMax? Beware of HypeVery few deployments of “real” WiMax No deployments of Mobile WiMax 23
  • 95. Wireless Tech of the Future 24
  • 96. Wireless Tech of the Future• Ultrawideband - Ultra Short Range - 2 to 3 x bandwidth over 802.11n 24
  • 97. Wireless Tech of the Future• Ultrawideband - Ultra Short Range - 2 to 3 x bandwidth over 802.11n• 60 - 70 Ghz - Extreme Bandwidth & Directionality 24
  • 98. Wireless Tech of the Future• Ultrawideband - Ultra Short Range - 2 to 3 x bandwidth over 802.11n• 60 - 70 Ghz - Extreme Bandwidth & Directionality• Super Mesh - 802.11s evolution? - Short Range is good - More Bandwidth! 24
  • 99. Wireless Tech of the Future 25
  • 100. Wireless Tech of the FutureNo Silver Bullets on the Horizon 25
  • 101. Wireless Common SenseShifting the Collection of Prejudices Robert J. Berger Internet Bandwidth Development Consulting rberger@ibd.com 26

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