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)
1
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 of Electromagnetic 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
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)
4
Propagation Received Power is inversely Proportional to Distance from The 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 Velocity Velocity 22
i
i
Interface rr
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Diffraction - Absorption Scattering
Incident
Incident
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Incident
Characteristics of Electromagnetic 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 Incident Ray Source
Interference
Velocity 1 Velocity Velocity 22
i
i
Interface rr
Velocity 1
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Electromagnetic spectrum Our Focus
Visible Light X-rays
Ultraviolet
Infrared
0.000000010.0000010.0001
0.01
Microwaves
1.0
Radio
100
10,000
Wavelength (in cm)
High Frequency
Low Frequency
Short Wavelength
Long Wavelength
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
Frequency and Wavelengths 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 – therefore 300,000 / 900,000 = 33.3 cm (~13”)
“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)
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
13
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. “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
15
Regulatory Issues for Cognitive Access Exempting cognitive equipment from the need for licensing with appropriate restrictions on when, where and how they might operate.
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
16
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 “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
17
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.
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
18
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
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
19
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 “Cognitive Radio Communications and Networks: Principles and Practice” 20 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? “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
21
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? “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
22
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” “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
23
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.
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
24
Spectrum Occupancy Studies
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)
25
Spectrum Occupancy Studies
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)
26
Spectrum Occupancy Studies
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)
27
Snapshot Studies Measured Spectrum Occupancy in Chicago and New York City PLM, Amateur, others: 30-54 MHz TV 2-6, RC: 54-88 MHz Air traffic Control, Aero Nav: 108-138 MHz Fixed Mobile, Amateur, others:138-174 MHz TV 7-13: 174-216 MHz Maritime Mobile, Amateur, others: 216-225 MHz Fixed Mobile, Aero, others: 225-406 MHz Amateur, Fixed, Mobile, Radiolocation, 406-470 MHz TV 14-20: 470-512 MHz TV 21-36: 512-608 MHz TV 37-51: 608-698 MHz TV 52-69: 698-806 MHz Cell phone and SMR: 806-902 MHz Unlicensed: 902-928 MHz Paging, SMS, Fixed, BX Aux, and FMS: 928-906 MHz IFF, TACAN, GPS, others: 960-1240 MHz Amateur: 1240-1300 MHz Aero Radar, Military: 1300-1400 MHz Space/Satellite, Fixed Mobile, Telemetry: 1400-1525 MHz Mobile Satellite, GPS, Meteorologicial: 1525-1710 MHz Fixed, Fixed Mobile: 1710-1850 MHz PCS, Asyn, Iso: 1850-1990 MHz TV Aux: 1990-2110 MHz Common Carriers, Private, MDS: 2110-2200 MHz Space Operation, Fixed: 2200-2300 MHz Amateur, WCS, DARS: 2300-2360 MHz Telemetry: 2360-2390 MHz U-PCS, ISM (Unlicensed): 2390-2500 MHz ITFS, MMDS: 2500-2686 MHz Surveillance Radar: 2686-2900 MHz
0.0%
Chicago New York City
25.0%
50.0%
75.0%
100.0%
Spectrum Occupancy
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
28
Spectrum Observatories
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)
29
Spectrum Observatories
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)
30
TV Spectrum Utilization
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)
31
Cellular Spectrum Utilization
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)
32
Paging Spectrum Utilization
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)
33
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
“Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
34
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 “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
35
