cognitive radio communications and networks: principles and practice by a. m. wyglinski, m. nekovee,...
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
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Chapter 2
Radio Frequency Spectrum and Regulation
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
The Basics
An understanding of the actual physics behind the layers of interactions in cognitive radio environments Provides a valuable basis for
understanding the rest of the topic!
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Characteristics ofElectromagnetic Waves
Radiate (stone in a pond) / light bulb Decrease in intensity with distance
(R2 Rule) from point of origin Can travel in straight line (lens / laser) Can be Reflected, Refracted, Diffused,
Scattered and Absorbed
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Electromagnetic Spectrum
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Photograph of the output of a prism on a table
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
PropagationReceived Power is inverselyProportional to Distance fromThe Transmitter(radius) Squared – the R2 Rule!
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Reflection / Refraction
Velocity 1
Reflectio
n
Refraction
Interface
Incident Rayi i
rVelocity 2 RefractionRefraction
Velocity 2Velocity 2 r
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Diffraction - Absorption - Scattering
IncidentIncident Incident
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Characteristics ofElectromagnetic Waves
Radiate (stone in a pond) Can travel in straight line (lens / laser) Decrease in Intensity with distance from
point of origin Can be Reflected, Refracted, Diffused,
Scattered, and Absorbed Even more exciting, waves can and do all
these things at the same time and based on mobility, dynamically change as well!
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Reflection / Refraction
Velocity 1
Reflectio
n
Interface
Incident Rayi i
rVelocity 2Refraction
Velocity 2 r
Velocity 1 Refraction
Reflection
Incident Ray
Interference
Source
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Electromagnetic spectrum
Our FocusVisible Light
X-rays Ultraviolet Infrared Microwaves Radio
0.000000010.0000010.0001 0.01 1.0 100 10,000
Wavelength (in cm)
High Frequency
Short Wavelength
Low Frequency
Long Wavelength
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Wavelength = Speed of Light / Frequency– or –
= c / f
for WiFi – 802.11b/g, f =~ 2.4 GHz and c = ~300,000 km / sec, therefore,
=~300,000 / 2,400,000 = 12.5 cm (~ 4.9”)
For low band cellular, f = 900 MHz – therefore300,000 / 900,000 = 33.3 cm (~13”)
Frequency and Wavelengths
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Cognitive Radio Challenges Interference! Co-existence Interoperability Complexity International Standards &
Regulations Power …
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
Should a Regulator Allow Cognitive Access? Deciding not to allow it (and hence do
nothing). Enabling existing license holders to
allow cognitive access into their own bands if they chose to.
Licensing cognitive access to particular bands.
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
Exempting cognitive equipment from the need for licensing with appropriate restrictions on when, where and how they might operate.
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
How to Determine the Rules of Entry If the regulator has decided to allow
cognitive access to a particular band, the next step in to set the rules of entry.
Rules ensure a very low probability of interference to the incumbent users of the band while at the same time placing the minimum possible restrictions on the cognitive device
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
The incumbents will be seeking the maximum level of protection Will seek out situations where the
“hidden node” problem or other signal modification issues are most extreme.
Even setting an appropriate level of probability of interference occurring can be fraught with difficulties.
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
Even setting an appropriate level of probability of interference occurring can be fraught with difficulties Many other rules are also needed
including: Maximum inband power Out-of-band power limits Bandwidth Transmit power control Sensing periodicity
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
Regulatory Implications of Different Methods of Cognition Geographical Databases
Access to a database listing the frequencies allowed to secondary use at each location.
Beacon Reception Transmission of a signal from some
appropriate infrastructure providing information on which frequencies are available for cognitive use
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
Geographical Databases To what accuracy should the device
know its location? Who will maintain the database? What availability is needed for the
database? How will devices download updated
versions of the database? What about dynamic use of spectrum?
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
Beacon Reception Who provides the beacon signal? How is the information the beacon is
transmitting kept up to date, especially where the licensed services are changing rapidly?
What spectrum is used for the beacon? What technical parameters and protocols
are used by the beacon transmitter?
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
Regulatory Developments to Date Most notably in November 2008 the FCC
published its Report and Order enabling cognitive access in the white space in the TV broadcast spectrum.
In July 2009 Ofcom published a statement on ”Licence-exempting Cognitive Devices Using Interleaved Spectrum”
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Regulatory Issues for Cognitive Access
The FCC concluded that sensing alone was insufficiently proven for cognitive access. Sensing alone would result in an
unacceptable risk of interference. Geographical databases were also
required.
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Spectrum Occupancy Studies
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Radio Car – circa 1927 (photo courtesy of the Institute for Telecommunications Science (ITS), NTIA, U.S. Dept. of Commerce)
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Spectrum Occupancy Studies
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WPI team prepare for an RF spectrum measurement sweep in downtown Rochester, NY.
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Spectrum Occupancy Studies
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A map of the forty eight locations close to I-90 between Boston, MA and Blandfield, MA over which spectrum measurements were collected in June 2009
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Snapshot Studies
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Measured Spectrum Occupancy in Chicago and New York City
0.0% 25.0% 50.0% 75.0% 100.0%
PLM, Amateur, others: 30-54 MHzTV 2-6, RC: 54-88 MHz
Air traffic Control, Aero Nav: 108-138 MHzFixed Mobile, Amateur, others:138-174 MHz
TV 7-13: 174-216 MHzMaritime Mobile, Amateur, others: 216-225 MHz
Fixed Mobile, Aero, others: 225-406 MHzAmateur, Fixed, Mobile, Radiolocation, 406-470 MHz
TV 14-20: 470-512 MHzTV 21-36: 512-608 MHzTV 37-51: 608-698 MHzTV 52-69: 698-806 MHz
Cell phone and SMR: 806-902 MHzUnlicensed: 902-928 MHz
Paging, SMS, Fixed, BX Aux, and FMS: 928-906 MHzIFF, TACAN, GPS, others: 960-1240 MHz
Amateur: 1240-1300 MHzAero Radar, Military: 1300-1400 MHz
Space/Satellite, Fixed Mobile, Telemetry: 1400-1525 MHzMobile Satellite, GPS, Meteorologicial: 1525-1710 MHz
Fixed, Fixed Mobile: 1710-1850 MHzPCS, Asyn, Iso: 1850-1990 MHz
TV Aux: 1990-2110 MHzCommon Carriers, Private, MDS: 2110-2200 MHz
Space Operation, Fixed: 2200-2300 MHzAmateur, WCS, DARS: 2300-2360 MHz
Telemetry: 2360-2390 MHzU-PCS, ISM (Unlicensed): 2390-2500 MHz
ITFS, MMDS: 2500-2686 MHzSurveillance Radar: 2686-2900 MHz
Spectrum Occupancy
Chicago
New York City
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Spectrum Observatories
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IIT’s Spectrum Observatory antenna array
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Spectrum Observatories
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SQUIRRELWeb spectrum measurement interface at WPI
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
TV Spectrum Utilization
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Spectrogram of TV channels 21 − 51 taken in Chicago 22 − 29 April 2008
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Cellular Spectrum Utilization
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Spectrogram of 800 MHz cellular band in Chicago taken 17−24 April 2008
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Paging Spectrum Utilization
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Wireless spectrum of 928-948 MHz in Rochester, NY on 19 June 2008.
“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Chapter 2 Summary
Nature of the electromagnetic spectrum with specific focus on that portion of the spectrum most useful for radio networks and communications systems
Cursory review of the early use of this spectrum has been presented
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“Cognitive Radio Communications and Networks: Principles and Practice”By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Chapter 2 Summary
Rise in national and international regulatory bodies focused on both the allocation of the spectrum and in defining the acceptable parameters for its use
Emerging unlicensed approaches to the use of the spectrum have been examined Cognitive access approach to spectrum
utilization
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