A Wireless Tipping Point, Open Spectrum Implications
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As presented at eComm Europe, October 2009. Are we using radio spectrum efficiently? No. Is this likely to change? Not soon. "Smart" radios have the potential to support much more efficient and productive use of spectrum, but spectrum regulation is a political issue with well established stakeholders. What's more, our limited experiments with commons-based spectrum management have had widely differing results: WiFi, enormous success; UltraWideBand, disappointment. WiFi's success happened in "junk" spectral bands where established players weren't interested. That will be difficult to repeat, but Brough will describe some very simple physical principals of radio propagation which, when combined with the next five years of Moore's law progress in semiconductors, suggest a path forward that's very different from TV white spaces. Indeed, the most important result of regulatory decisions on UltraWideBand and TV white spaces is they validate the concept of secondary access.
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A Wireless Tipping Point, Open Spectrum Implications
- 1. A Wireless Tipping Point, Open Spectrum Implications Brough Turner http://www.broughturner.com
- 2. 1920s consumer radio receivers Philips 2501 Very early tech, i.e. primitive Crystal, Regenerative, Tuned RF … Poor selectivity, low sensitivity, low stability Tuned RF Crystal 2
- 3. Radio Spectrum Occupancy Urban areas, 30 MHz to 3 GHz. Above 3 GHz mostly vacant. As measured by Shared Spectrum Company and the University of Kansas Center for Research for the NSF National Radio Network Research Testbed (NRNRT) 3
- 4. New York City Unusually heavy communications during Republican National Convention August 30 to September 3, 2004 brought spectrum occupancy up to 13%. 4
- 5. Most spectrum idle most of the time 806 – 928 MHz Dublin Ireland Spectrum Occupancy Measurements Collected On April 16-18, 2007 Shared Spectrum Company, www.sharedspectrum.com 5
- 6. Most spectrum idle most of the time 806 – 928 MHz Dublin Ireland Spectrum Occupancy Measurements Collected On April 16-18, 2007 Shared Spectrum Company, www.sharedspectrum.com 6
- 7. Most spectrum idle most of the time 806 – 928 MHz Dublin Ireland Spectrum Occupancy Measurements Collected On April 16-18, 2007 Shared Spectrum Company, www.sharedspectrum.com 7
- 8. Open Spectrum Noise, Interference, Chaos … ! How could it work? 8
- 9. Open Spectrum Noise, Interference, Chaos … ! How could it work? Focus on Receiver Performance 9
- 10. Visible light analogy Our vision system (eyes + visual cortex) = extremely efficient 400-790 THz receiver The product of years of evolution! 10
- 11. Spatial discrimination For Humans: ~ 1/60th of a degree 11
- 12. Enormous knowledge base Detailed catalog of the characteristics of most potential visible light sources 12
- 13. Leveraging source motion to increase received information … 13
- 14. 1920: Regulation made sense 14
- 15. 1920: Regulation made sense 2009: We’ve come a long way 15
- 16. 1920: Regulation made sense 2009: We’ve come a long way Shared use of unlicensed spectrum Enormous value creation 16
- 17. 1920: Regulation made sense 2009: We’ve come a long way Shared use of unlicensed spectrum Enormous value creation Thermex Thermatron RF Dryers 17
- 18. Open spectrum prospects Regulation Vested interests TV White Spaces Crippled for now… 18
- 19. Open spectrum prospects Regulation Vested interests TV White Spaces Crippled for now… What about higher frequencies? 19
- 20. Spectrum Myth TV Spectrum is “beach front” spectrum 20
- 21. Spectrum Myth TV Spectrum is “beach front” spectrum Based on legacy technology, not physics! Travels farther – No! Goes thru walls – Not that different… 21
- 22. Refraction and reflections More at shorter wavelengths Multiple versions “Multipath” 22
- 23. MIMO: Multiple Input Multiple Output Multiple paths improve link reliability and increase spectral efficiency (bps per Hz), range and directionality 23
- 24. Rich Indoor MIMO Multipath Source: Fanny Mlinarsky, Octoscope 24
- 25. Municipal Multipath Environment Source: Fanny Mlinarsky, Octoscope 25
- 26. TVWS – Beach-front Property? MIMO antenna separation >= ½ wavelength 2.1 meters at 70 MHz 21 cm at 700 MHz But 2.5 cm for 5.8 GHz Wi-Fi D-Link DAP-2553 Wavion Networks 26
- 27. Multiple radios per chip Like CPU cores … Intel 2x2 MIMO – 2008 4x4 MIMO – 2010-11 then Fujitsu 8 radios, 16 radios?, … what to use the silicon for? Beam-forming ! AMD 27
- 28. Beamforming 2014: >200 Mbps Wi-Fi to >1 Km at mass market prices ? 4x4 MIMO with 12-16 antenna elements 28
- 29. Beamforming 2014: >200 Mbps Wi-Fi to >1 Km at mass market prices ? 4x4 MIMO with 12-16 antenna elements 29
- 30. Gaining spectrum for open use Seeking only “Secondary access” No interference with existing users Geographic database; Listen-before-talk License-exempt stations under positive control of a “lightly” licensed station 30
- 31. Wi-Fi 802.11y - 2008 Rich protocol set for “secondary access” 31
- 32. Open spectrum Wireless tipping point ahead Focus on spectrum blocks above 3 GHz More access at 5 GHz (4.9-6 GHz) Anything between 6-10 GHz “Secondary use” Light licensing – 802.11y protocols 32
- 33. Thank You Brough Turner broughturner@gmail.com rbt@ashtonbrooke.com
- 34. Credits Beyond those noted on individual pages… Images… Office building facade: http://commons.wikimedia.org/wiki/User:Beek100 Laptop icon: http://www.flickr.com/photos/ichibod/ Microwave oven: http://www.flickr.com/photos/code_martial/ 802.11n performance in the field http://www.tomshardware.com/reviews/beamforming-wifi-ruckus,2390.html http://www.muniwireless.com/2009/02/23/80211n-dramatically-improves- outdoor-wifi/ 34