Proposal for Part 15.244 Cognitive Radio Operation in the TV Band

1
Proposal for Part 15.244 Cognitive Radio
Operation in the TV Band
IEEE 802.18 Radio Regulatory TAG
2
Outline

• Introduction
• TV Band Incumbents
• Identifying Characteristics of Incumbents
• Elements of Cognitive Radio Operation
• Proposed Cognitive Radio Rules
• Analysis for Personal/Portable Devices
• Operating Range of Personal/Portable Devices
• Detection of DTV Signals
• DFS Sensitivity vs DTV Service Contour Field
  Strength
• Co-Channel Interference Range Margin
• Terrain Blocking
• Analysis for Fixed Devices
• Wrap Up

3
Introduction
Kenwood FreeTalk XL and the TalkAbout Distance
and DPS radios use GMRS - "General Mobile Radio
Service" UHF frequencies with 2 watts of output
power. Channels 1 - 7 on the FreeTalk XL and
Motorola Distance and DPS radios are compatible
with channels 1 - 7 on all Motorola FRS radios.
In most circumstances, with the exception of
mountainous and ski environments, 2 Kenwood
FreeTalk XL radios will talk twice as far as 2
Motorola TalkAbout FRS radios. When used from
inside a lodge or condo, because the
obstructions, there is usually a significant
increase in range using these radios. We have not
seen large increases in range when used skiing on
the same slope. This has been in situations where
the radios have been used from the top of the
slope to the bottom with a clear line of sight
path. The benefit of the 2 watts of power output
shows best when they are used in very thick
woodlands or dense steel and/or concrete
buildings. The extra power of the Kenwood
FreeTalk XL really pays off for campers, hikers,
and hunters.
Many other factors can affect the range of these
radiosTerrain - flat land, hills, or mountains
Foliage - woodlands, jungle, plains, or urban
areas Weather Buildings and StructuresBattery
Condition The range you can expect will vary
depending upon the conditions and terrain you use
the radios in. General "Rule of Thumb" for
Radio Range All other factors being equal To
achieve twice the range, 4 times the output power
is necessary. If the antenna height is tripled
then you have the potential to double your range.
These concepts are very broad "rules of thumb"
and your results may vary.
On site business radios such as the Kenwood
ProTalk T3100 or Motorola Spirit use UHF
frequencies very similar to UHF GMRS frequencies.
Performance of these radios will be identical to
the UHF GMRS radios listed above. Kenwood ProTalk
TK3100 radios can be dealer programmed for use on
commercial UHF repeater systems.
2 Watt UHF GMRS RadiosFreeTalk XL TK3101
ProTalk TK3100 Motorola TalkAbout Distance
VHF frequencies are better suited for outdoor
applications requiring maximum coverage areas.
The VHF signals penetrate natural foliage and
vegetation much better than the higher UHF
frequencies. VHF frequencies are more susceptable
to man made objects like steel, steel reinforced
concrete buildings. In most cases, outdoors in
rural environments a 2 watt VHF radio will have
50 more range than a 2 watt UHF radio.
1 Watt UHFGMRS RadiosFreeTalk XLSProTalk XLS
1/2 Watt FRSFamily RadiosMotorola TallkAbout FRS
2 Watt VHF RadiosProTalk TK21002 Watt MURS
FRS radios like the Motorola TalkAbout use
"Family Radio Service" UHF frequencies and do not
require a FCC license. FRS radios are required to
have a maximum 1/2 watt power output. Their range
is normally 1/2 of the GMRS 2 watt radios.
OutsideClear Flat Terrain
1/2 to 3/4 mile15 floors
1 mile20 floors
1/2 mile10 Floors
                                            More
Kenwood Radio Information
Two Way Radio Range Guidelines
FRS Radios
GMRS Radios
2 Watt UHF Business Radios
2 Watt VHF Business and MURS Radios
Other Factors
Terrain
1.5 to 2 miles
2 to 3 miles
3 to 4 miles
3 to 5 miles
Suburban Neighborhoods
1 to 1.5 miles
1 to 2 miles
1.5 to 2 miles
1.5 to 3 miles
Urban Areas
1/2 to 1 mile
1/2 to 1.5 miles
1 to 1.5 miles
1 to 1.5 miles
Inside Buildings or Malls
1/2 mile or 5 floors
Between Buildings or Houses
1/8 to 1/2 mile
1/2 to 1 mile
1/2 to 2 miles
1 to 3 miles
Woodlands, Moderate Vegetation
1 to 1.5 miles
1 to 2 miles
1.5 to 2 miles
2 to 3 miles
Woodlands, Thick Vegetation
1/2 to 1 mile
1/2 to 1.5 miles
1 to 1.5 miles
1.5 to 2 miles These figures are averages based
upon our tests and customer feedback. Your
results will vary depending upon obstructions,
elevation, terrain, vegetation and building
construction.
TK3101 FreeTalk XL
TK3131 FreeTalk XLS
TK3100 UHF ProTalk
TK3130 ProTalk XLS
TK2100 VHF ProTalk
Accessories
Frequencies and Codes
FCC Licensing Info


                                                  

• On May 13, 2004, the FCC adopted ET Docket No.
  04-186, Unlicensed Operation in the TV Broadcast
  Bands in a Notice of Proposed Rulemaking (NPRM).
• As written, ET-04-186 proposes the following two
  classes of devices under a new rules section,
  Part 15.244
• Personal/Portable Devices
• 100 mW peak transmitter power, 400 mW peak EIRP
  (6 dBi antenna)
• Transmission is permitted only when receiving a
  control signal indicating which TV channels are
  vacant from one of the following sources a TV
  Broadcast station, an FM Broadcast station, or an
  unlicensed transmitter
• Fixed Access Devices
• 1 W peak transmitter power, 4 W peak EIRP (6 dBi
  antenna)
• Must meet one of the following criteria
• Include a GPS receiver and means of determining
  vacant TV channels in the area
• Be installed by professionals to operate only on
  unused channels.

4
Introduction
Kenwood FreeTalk XL and the TalkAbout Distance
and DPS radios use GMRS - "General Mobile Radio
Service" UHF frequencies with 2 watts of output
power. Channels 1 - 7 on the FreeTalk XL and
Motorola Distance and DPS radios are compatible
with channels 1 - 7 on all Motorola FRS radios.
In most circumstances, with the exception of
mountainous and ski environments, 2 Kenwood
FreeTalk XL radios will talk twice as far as 2
Motorola TalkAbout FRS radios. When used from
inside a lodge or condo, because the
obstructions, there is usually a significant
increase in range using these radios. We have not
seen large increases in range when used skiing on
the same slope. This has been in situations where
the radios have been used from the top of the
slope to the bottom with a clear line of sight
path. The benefit of the 2 watts of power output
shows best when they are used in very thick
woodlands or dense steel and/or concrete
buildings. The extra power of the Kenwood
FreeTalk XL really pays off for campers, hikers,
and hunters.
Many other factors can affect the range of these
radiosTerrain - flat land, hills, or mountains
Foliage - woodlands, jungle, plains, or urban
areas Weather Buildings and StructuresBattery
Condition The range you can expect will vary
depending upon the conditions and terrain you use
the radios in. General "Rule of Thumb" for
Radio Range All other factors being equal To
achieve twice the range, 4 times the output power
is necessary. If the antenna height is tripled
then you have the potential to double your range.
These concepts are very broad "rules of thumb"
and your results may vary.
On site business radios such as the Kenwood
ProTalk T3100 or Motorola Spirit use UHF
frequencies very similar to UHF GMRS frequencies.
Performance of these radios will be identical to
the UHF GMRS radios listed above. Kenwood ProTalk
TK3100 radios can be dealer programmed for use on
commercial UHF repeater systems.
2 Watt UHF GMRS RadiosFreeTalk XL TK3101
ProTalk TK3100 Motorola TalkAbout Distance
VHF frequencies are better suited for outdoor
applications requiring maximum coverage areas.
The VHF signals penetrate natural foliage and
vegetation much better than the higher UHF
frequencies. VHF frequencies are more susceptable
to man made objects like steel, steel reinforced
concrete buildings. In most cases, outdoors in
rural environments a 2 watt VHF radio will have
50 more range than a 2 watt UHF radio.
1 Watt UHFGMRS RadiosFreeTalk XLSProTalk XLS
1/2 Watt FRSFamily RadiosMotorola TallkAbout FRS
2 Watt VHF RadiosProTalk TK21002 Watt MURS
FRS radios like the Motorola TalkAbout use
"Family Radio Service" UHF frequencies and do not
require a FCC license. FRS radios are required to
have a maximum 1/2 watt power output. Their range
is normally 1/2 of the GMRS 2 watt radios.
OutsideClear Flat Terrain
1/2 to 3/4 mile15 floors
1 mile20 floors
1/2 mile10 Floors
                                            More
Kenwood Radio Information
Two Way Radio Range Guidelines
FRS Radios
GMRS Radios
2 Watt UHF Business Radios
2 Watt VHF Business and MURS Radios
Other Factors
Terrain
1.5 to 2 miles
2 to 3 miles
3 to 4 miles
3 to 5 miles
Suburban Neighborhoods
1 to 1.5 miles
1 to 2 miles
1.5 to 2 miles
1.5 to 3 miles
Urban Areas
1/2 to 1 mile
1/2 to 1.5 miles
1 to 1.5 miles
1 to 1.5 miles
Inside Buildings or Malls
1/2 mile or 5 floors
Between Buildings or Houses
1/8 to 1/2 mile
1/2 to 1 mile
1/2 to 2 miles
1 to 3 miles
Woodlands, Moderate Vegetation
1 to 1.5 miles
1 to 2 miles
1.5 to 2 miles
2 to 3 miles
Woodlands, Thick Vegetation
1/2 to 1 mile
1/2 to 1.5 miles
1 to 1.5 miles
1.5 to 2 miles These figures are averages based
upon our tests and customer feedback. Your
results will vary depending upon obstructions,
elevation, terrain, vegetation and building
construction.
TK3101 FreeTalk XL
TK3131 FreeTalk XLS
TK3100 UHF ProTalk
TK3130 ProTalk XLS
TK2100 VHF ProTalk
Accessories
Frequencies and Codes
FCC Licensing Info


                                                  

• Although ET 04-186 seeks comment on the
  possibility of using spectrum sensing, and other
  cognitive radio techniques, to identify and avoid
  TV channels occupied by an incumbent, and select
  channels for unlicensed operation, the
  Commissions proposed rules sections do not
  permit that approach.
• This presentation does the following
• Proposes a set of rules for an additional class
  of devices which permit cognitive radio
  technologies to be used in unlicensed devices
  operating in the TV band under Part 15.244.
• Establishes that devices operating under these
  rules protect the operations of TV band
  incumbents based on widely available operational
  data and supporting analysis.

5
TV Band Incumbents
Kenwood FreeTalk XL and the TalkAbout Distance
and DPS radios use GMRS - "General Mobile Radio
Service" UHF frequencies with 2 watts of output
power. Channels 1 - 7 on the FreeTalk XL and
Motorola Distance and DPS radios are compatible
with channels 1 - 7 on all Motorola FRS radios.
In most circumstances, with the exception of
mountainous and ski environments, 2 Kenwood
FreeTalk XL radios will talk twice as far as 2
Motorola TalkAbout FRS radios. When used from
inside a lodge or condo, because the
obstructions, there is usually a significant
increase in range using these radios. We have not
seen large increases in range when used skiing on
the same slope. This has been in situations where
the radios have been used from the top of the
slope to the bottom with a clear line of sight
path. The benefit of the 2 watts of power output
shows best when they are used in very thick
woodlands or dense steel and/or concrete
buildings. The extra power of the Kenwood
FreeTalk XL really pays off for campers, hikers,
and hunters.
Many other factors can affect the range of these
radiosTerrain - flat land, hills, or mountains
Foliage - woodlands, jungle, plains, or urban
areas Weather Buildings and StructuresBattery
Condition The range you can expect will vary
depending upon the conditions and terrain you use
the radios in. General "Rule of Thumb" for
Radio Range All other factors being equal To
achieve twice the range, 4 times the output power
is necessary. If the antenna height is tripled
then you have the potential to double your range.
These concepts are very broad "rules of thumb"
and your results may vary.
On site business radios such as the Kenwood
ProTalk T3100 or Motorola Spirit use UHF
frequencies very similar to UHF GMRS frequencies.
Performance of these radios will be identical to
the UHF GMRS radios listed above. Kenwood ProTalk
TK3100 radios can be dealer programmed for use on
commercial UHF repeater systems.
2 Watt UHF GMRS RadiosFreeTalk XL TK3101
ProTalk TK3100 Motorola TalkAbout Distance
VHF frequencies are better suited for outdoor
applications requiring maximum coverage areas.
The VHF signals penetrate natural foliage and
vegetation much better than the higher UHF
frequencies. VHF frequencies are more susceptable
to man made objects like steel, steel reinforced
concrete buildings. In most cases, outdoors in
rural environments a 2 watt VHF radio will have
50 more range than a 2 watt UHF radio.
1 Watt UHFGMRS RadiosFreeTalk XLSProTalk XLS
1/2 Watt FRSFamily RadiosMotorola TallkAbout FRS
2 Watt VHF RadiosProTalk TK21002 Watt MURS
FRS radios like the Motorola TalkAbout use
"Family Radio Service" UHF frequencies and do not
require a FCC license. FRS radios are required to
have a maximum 1/2 watt power output. Their range
is normally 1/2 of the GMRS 2 watt radios.
OutsideClear Flat Terrain
1/2 to 3/4 mile15 floors
1 mile20 floors
1/2 mile10 Floors
                                            More
Kenwood Radio Information
Two Way Radio Range Guidelines
FRS Radios
GMRS Radios
2 Watt UHF Business Radios
2 Watt VHF Business and MURS Radios
Other Factors
Terrain
1.5 to 2 miles
2 to 3 miles
3 to 4 miles
3 to 5 miles
Suburban Neighborhoods
1 to 1.5 miles
1 to 2 miles
1.5 to 2 miles
1.5 to 3 miles
Urban Areas
1/2 to 1 mile
1/2 to 1.5 miles
1 to 1.5 miles
1 to 1.5 miles
Inside Buildings or Malls
1/2 mile or 5 floors
Between Buildings or Houses
1/8 to 1/2 mile
1/2 to 1 mile
1/2 to 2 miles
1 to 3 miles
Woodlands, Moderate Vegetation
1 to 1.5 miles
1 to 2 miles
1.5 to 2 miles
2 to 3 miles
Woodlands, Thick Vegetation
1/2 to 1 mile
1/2 to 1.5 miles
1 to 1.5 miles
1.5 to 2 miles These figures are averages based
upon our tests and customer feedback. Your
results will vary depending upon obstructions,
elevation, terrain, vegetation and building
construction.
TK3101 FreeTalk XL
TK3131 FreeTalk XLS
TK3100 UHF ProTalk
TK3130 ProTalk XLS
TK2100 VHF ProTalk
Accessories
Frequencies and Codes
FCC Licensing Info


                                                  

• Full Service TV Broadcast Stations (CFR1 Title
  47 Part 73).
• Class A TV Broadcast Stations (CFR Title 47 Part
  73 subpart J).
• LPTV, TV Translator, TV Booster Stations,
  Auxiliary Operations, and Wireless Microphones
  (CFR Title 47 Part 74).
• Private Land Mobile Radio Services (PLMRS) in 13
  Metro Areas (CFR Title 47 Part 90), including
  Public Safety communications systems.
• Commercial Land Mobile Radio Services (CMRS) in
  13 Metro Areas (CFR Title 47 Part 20).
• Wireless Medical Telemetry Services (WMTS) (CFR
  Title 47 Part 95 subpart H).

6
TV Band Incumbent Protection from Cognitive
Devices

• In order to insure that public safety operations
  are protected, Ch 14-20 are excluded from the
  proposed cognitive radio class of operation.
• Wireless Medical Telemetry Services operate on
  Ch 37 within the TV band, which is excluded by
  the Commissions proposed rules from Part 15.244
  device operations.
• Wireless microphone operation as a Low Power
  Auxiliary Station under Part 74 can protected by
  cognitive techniques, or by rule (assignment to
  specific channels in each service area, etc).
  This presentation does not address wireless
  microphones.
• Wireless video assist devices are provided for as
  Low Power Auxiliary Devices in Part 74, but no
  equipment is presently authorized or licensed for
  operation. This class of equipment should be
  considered for termination.
• The remaining incumbents are TV broadcast
  signals, which, because of their unique
  signatures (analog/NTSC, and digital/ATSC), are
  readily identifiable.

7
Analog TV (NTSC) Spectrum

• Power primarily confined to Video and Audio
  carriers.
• Distinctive double peaked spectrum makes
  identification by spectrum profiling relatively
  easy.
• Relatively high narrowband power levels compared
  to DTV.

8
Digital TV (ATSC) Spectrum

• Power spread over center 5.38 MHz within a TV
  channnel.
• Pilot tone is a distinctive feature when observed
  in a narrowband receiver.
• Pilot tone power is 11.3 dB below average power
  measured in a 6 MHz bandwidth.

9
Elements of Cognitive Radio Operation (1)

• Network Frequency Allocation (NFA)
• Survey and monitor spectrum use patterns.
• Avoid incumbents, operate network on an unused or
  lightly used channel.
• Link Power Control (LPC)
• Keep network transmitter power low while
  maintaining good link quality.
• LPC mitigates interference and promotes frequency
  reuse with networks located nearby.
• Incumbent Profile Detection (IPD)
• Detect incumbent users based on specific spectrum
  signature (supports NFA)
• Example detecting the presence of a sound/video
  carriers in NTSC (analog TV) systems or a pilot
  tone in ATSC (DTV) systems.
• Collision Detection And Avoidance (CDAA)
• Transmitters wait until the channel is quiet
  before transmitting (listen before talk).
• A receiving node acknowledges valid data by
  transmitting a response.
• A transmitting node detects a collision if it
  does not receive an acknowledgement before a
  timeout occurs.
• The protocol implements an appropriate
  backoff/retry timing mechanism for retransmission
  when a collision is detected.

1. Notor, J., Radio Architectures for Unlicensed
Reuse of Broadcast TV Channels, Communications
Design Conference 2003.
10
Proposed Cognitive Radio Rules

• These rules extend the FCCs proposed rules for
  Part 15.244 devices to authorize cognitive radio
  techniques.
• Dynamic Frequency Selection (DFS) threshold a TV
  channel shall be considered unoccupied when the
  electric field strength at the receiving antenna
  is less than the following averaged for 10 ms
  over the entire 6 MHz channel.
• For Ch 5-6, E(dBu) lt -7 dBuV/m/10 kHz
• For Ch 7-13, E(dBu) lt 1 dBuV/m/10 kHz
• For Ch 21-51, excluding Ch 37 E(dBu) lt 11
  dBuV/m/10 kHz
• To operate on a channel whose ambient field
  strength is greater than the DFS threshold, the
  cognitive device must, using appropriate
  Incumbent Profile Detection techniques, verify
  that the channel is not being occupied by either
  an analog or a digital TV signal.
• The cognitive radio network shall give priority
  to operation on empty or lightly occupied
  channels.

11
Proposed Cognitive Radio Rules

• Transmit Power Control (TPC)
• Link Power Control protocols must be included in
  the cognitive radio devices to minimize
  transmitter power while supporting reliable
  communications between any transmitter and any
  single receiver.
• The LPC protocol operation shall cause the
  transmitter in any single node to single node
  link to begin reducing output power when the
  signal level at the receiver is greater than 20
  dB above the receivers nominal sensitivity.
• The TPC function shall keep the signal level at
  the receiver less than 30 dB above the receivers
  nominal sensitivity at least 50 of the time,
  including the impact of any regular broadcast
  operations (transmission from a controlling node
  to all other nodes).
• Listen Before Talk
• The transmitters must operate in burst mode, with
  a maximum continuous burst length less than 1
  second.
• Cognitive radio devices must monitor the
  operational channel periodically to verify that
  the channel remains unoccupied by an analog or
  digital TV signal.

12
Analysis for Personal/Portable Devices

• The following analyses establishes the
  performance limits of cognitive radio operation
  for personal/portable devices
• Expected loss exponent (L.E.) for
  personal/portable operation.
• Detection performance for DTV signals.
• DFS sensitivity margin.
• Co-channel interference range margin.
• Terrain blocking footprint and issues.

13
Operating Range of Personal/Portable Devices
Table 1 Range data based on customer survey
information (2)
2. Table provided by Southern Communications and
Electronics at the following web
site http//www.southernce.com/cgi-bin/SoftCart.e
xe/range.htm?Lscstorejosy37491088643303
14
Operating Range of Personal/Portable Devices

• VHF Loss Exponent estimates based on the
  operational characteristics of MURS radio
  handsets (151.820 MHz lt fc lt 154.600 MHz).
• Sensitivity 0.2 uV at limit of range, or -121
  dBm
• Antenna Gain 0 dBi
• Tx Power 2 W (33 dBm)
• Loss to limit of sensitivity 33 (-121) 154
  dB.
• Loss Exponent (LE) 154/10log(d), where d is
  the range in m.
• Table 2 Anecdotal range data based on Table 1
  with loss exponent

Est. Range (m) LE Conditions
6436 4.0 Outdoors, clear flat terrain
3620 4.3 Suburban outdoor environments
2011 4.7 Urban outdoor environments
805 5.3 Inside shopping mall
15
Operating Range of Personal/Portable Devices

• UHF Loss Exponent estimates based on the
  operational characteristics of FRS radio handsets
  (462.5625 MHz lt fc lt 467.7125 MHz).
• Sensitivity 0.2 uV at limit of range, or -121
  dBm
• Antenna Gain 0 dBi
• Tx Power 500 mW (27 dBm)
• Loss to limit of sensitivity 27 (-121) 148
  dB.
• Loss Exponent (LE) 148/10log(d), where d is
  the range in m.
• Table 3 Anecdotal range data from various
  sources with loss exponent

Data Source Est. Range (m) LE Conditions
Manufacturers 3218 4.2 Over water
McGuinn 2413 4.4 Hotel to hotel, 15th story room to lobby, Disney World
Various 1609 4.6 Normal cluttered outdoor environment
Notor 984 4.9 Outdoors in Willow Glen Neighborhood, San Jose, CA
Other 402 5.7 Inside shopping mall
16
Operating Range of Personal/Portable Devices

• VHF/UHF Loss Exponent (LE) range 4-5.7
• Loss exponents by environment
• Clear flat terrain LE 4
• Outdoor suburban/urban environment LE 4.3 -
  4.9
• Indoor to indoor, 15th floor hotel room to hotel
  lobby LE 4.4
• Inside shopping mall 5.3-5.7
• Operational experience based on loss exponent
  analysis tracks well between VHF and UHF portable
  radios.

17
Detection of DTV Signals

• DTV is the limiting case re DFS/IPD for TV
  signals.
• Receiver Assumptions
• CNR 6 dB is sufficient for detection of a
  narrowband signal like an ATSC pilot tone.
• NF 5 dB
• Antenna Gain 0 dBi
• Predetection Bandwidth 10 kHz
• Post Detection Time Constant 10 ms
• Square Law Detector
• Sensitivity Calculation (CNR 6 dB)
• S -174 dBm/Hz 10log(10 kHz) 5 dB 6 dB
• S -123 dBm

18
Detection of DTV Signals

• For a DFS detection threshold of -123 dBm/10 kHz
  applied to identifying a DTV signal by detecting
  the pilot tone, the equivalent clear channel DFS
  threshold for a DTV signal becomes
• DTV DFS -123 dBm 11.3 dB -111.7 dBm -112
  dBm in a 6 MHz bandwidth
• -112 dBm is below the thermal noise floor for a 6
  MHz bandwidth, i.e. Np -174 dBm 10log(6 MHz)
  -106.2 dBm gt -112 dBm, but the analysis remains
  valid, since the pilot tone can be detected in a
  10 kHz bandwidth.
• Assuming a 0 dBi antenna and a 50 Ohm reference
  impedance, the equivalent DFS threshold in terms
  of electric field strength in a 6 MHz bandwidth
  is
• E(dBu) P(dBm) 20logf(MHz) 77.2
• For Ch 6, E(dBu) -112 20log85 77.2 4
  dBuV/m
• For Ch 13, E(dBu) 12 dBuV/m
• For Ch 51, E(dBu) 22 dBuV/m

19
DFS Sensitivity Margin - Personal/Portable Devices

• The sensitivity margin relative to the minimum
  in-service DTV field strength for a 30 ft high
  receive antenna is
• For Ch 6, margin 28 4 24 dB
• For Ch 13, margin 36 12 24 dB
• For Ch 51, margin 41 22 19 dB
• For a receiver outdoor antenna height of 2 m
  (nomadic personal/portable device), reduce the
  sensitivity margin by a 9 dB correction factor
  (3).
• Table 4 (p.19) shows sensitivity margin
  calculations for various stations in the FCC
  database, using the FCC calculator at
  http//www.fcc.gov/mb/audio/bickel/curves.html.
• The DFS detector operating outdoors with an
  antenna height of 2 m can sense a TV channel
  outdoors at ranges gt 21 farther than the service
  contour (Table 4) in unobstructed terrain.

3. Mehrotra, A., Cellular Radio Performance
Engineering, Artech House, 1994, p146
20
Table 4 DFS Sensitivity Margin
Personal/Portable Devices
          Service        
          Area Contour DFS (4) DFS Range Range
  DTV Band HAAT ERP Limit Range Limit Range Margin Margin
Station, Locale Ch (MHz) (m) (kW) (dBu) (km) (dBu) (km) (km) ()
WCFT-TV, Tuscaloosa, AL 5 76-82 625.4 9.5 28 128.7 12 182.4 53.7 41.7
KNSO, Merced, CA 5 76-82 575.0 11.0 28 126.5 12 181.7 55.2 43.6
KYES, Anchorage, AK 6 82-88 277.0 45.0 28 120.5 13 180.5 60.0 49.8
WEDY, New Haven, CT 6 82-88 88.0 0.4 28 56.0 13 83.9 27.9 49.8
KMBC-TV, Kansas City, MO 7 174-180 357.0 85.0 36 114.7 19 173.6 58.9 51.4
KNTV, San Jose, CA 12 204-210 376.6 103.1 36 118.2 20 174.7 56.5 47.8
WDAF-TV,Kansas City, MO 34 590-596 295.0 1000.0 41 96.2 30 125.1 28.9 30.0
KLCS, Los Angeles, CA 41 626-632 900.8 162.0 41 115.5 30 140.5 25.0 21.6
WMSY-TV, Marion, VA 42 638-644 448.0 100.0 41 89.8 30 112.9 23.1 25.7
KWDK, Tacoma, WA 42 638-644 695.0 144.0 41 107.0 31 129.7 22.7 21.2
WTVX, Fort Pierce, FL 50 686-692 438.3 704.0 41 106.0 31 132.2 26.2 24.7
KOPX, Oklahoma City, OK 50 686-692 483.0 200.0 41 97.8 31 120.1 22.3 22.8
KDTV, San Francisco, CA 51 692.698 701.0 476.3 41 118.5 31 144.1 25.6 21.6
4. The DFS limit is calculated at a 2 m antenna
height, assuming a 9 dB loss relative to signal
strength at 30 ft (9 m). So, for Ch 6, DFS Limit
4 dBuV/m 9 dB 13 dBu. These calculations
exclude terrain blockage effects.
21
Co-Channel Interference Range Margin

• Part 15.244 Device Tx Operating Parameters
• EIRP 400 mW, or 26 dBm
• E(dBu) 104.8 EIRP(dBm) 20log(D) 131 dBu
  at D 1 m.
• Loss exponent (LE) 4 (lower limit of operational
  experience for portable devices).
• DTV Co-channel D/U 23 dB at the edge of the
  service area.
• Maximum allowed co-channel interference field
  strength at the edge of the service contour (Full
  service DTV)
• Ch 5-6 28 23 5 dBu
• Ch 7-13 36 23 13 dBu
• Ch 14-51 41 23 18 dBu
• Interference Range (R), LE 4, to DTV co-channel
  D/U 23 dB limit
• Ch 5-6 R 10(131 5) / 40 1.4 km
• Ch 7-13 R 891 m
• Ch 14-51 R 668 m

22
Co-Channel Interference Range Margin

• FCC propagation calculations indicate that a
  unlicensed spectrum sensing device operating
  outdoors can sense a DTV signal 22-60 km outside
  the service contour of a DTV station, excluding
  terrain blocking effects.
• The range of a Part 15.244 personal/portable
  device transmitter operating at a 26 dBm EIRP to
  the field strength limit for an undesired
  co-channel signal within a service contour is 668
  m to 1.4 km.
• So, DTV services areas are protected by a buffer
  zone (excluding terrain blockage effects) of
  greater than 20 km using spectrum sensing
  techniques.

23
Co-Channel Interference Range Margin
Limit of DFS Sensing Capability
DTV Service Area
22-60 km
Edge of Service Contour
Cognitive Radio Range to 23 dB D/U Limit
R lt1.4 km (26 dBm EIRP, LE 4)
24
Terrain Blocking

• Reduces the available signal level significantly
  in the blocked area relative to adjacent
  unblocked areas due to terrain features
  mountains, buildings, interior walls. Example
  terrain blocking losses
• 40 dB over an 8 km stretch in Virginia for 50 of
  the cases, much fewer instances of 40 dB change
  for smaller geographic segments (5)
• 37 dB over a 4 km stretch in Boulder, CO (6)
  (see p24)
• 27 dB over an 2.4 km stretch (7) in Boulder, CO
  (see p.25)
• 10 dB for building shadowing losses, and 10-20 dB
  for building penetration losses (8,9) (see p 26).
  Note For the data in Table 5, the indoor
  antenna was placed next to a window on the same
  side of the building where the outdoor signal
  strength was measured, which tends to produce
  more optimistic results than otherwise.
• Reduces the range margin at the edge of a service
  contour over that available in an unblocked
  situation.

5. McHenry Byrnes, Shared Spectrum Company
Comments to FCC ET-02-380, p9 6. Holoway,
Sanders, McKenna, NTIA Report 01-387, p24 and
Figure 14 7. Holoway, Sanders, McKenna, NTIA
Report 01-387, p24 and Figure 16 8. McHenry
Byrnes, Shared Spectrum Company Comments to FCC
ET-02-380, p.6 8. Salehian, Khalil, Comparison
Between the Field Strength of DTV Signals Inside
and Outside of the Buildings, Communications
Research Centre Canada.
25
Geographic Terrain Blocking
4 km
1.3 V/m
37 dB
0.018 V/m
Figure 14 reproduced from Holoway, Sanders,
McKenna, NTIA Report 01-387
26
Geographic Terrain Blocking
2.4 km
1.2 V/m
27 dB
0.055 V/m
Figure 16 reproduced from Holoway, Sanders,
McKenna, NTIA Report 01-387
27
Terrain Blocking By Buildings
Table 5 Outdoor to Indoor Propagation Data (10)
Site Number Outdoor Outdoor Indoor Floor Outdoor 10 m - Outdoor 2m (dB) Outdoor 10 m - Indoor (dB)
Site Number 10 meters 2 meters Indoor Floor Outdoor 10 m - Outdoor 2m (dB) Outdoor 10 m - Indoor (dB)
2 -54.6 -72 -62.2 2 17.4 7.60
3 -71 -77 -70 2 6 -1.00
4 -35.3 -47.2 -51 1 11.9 15.70
4 -35.3 -47.2 -34.6 2 -0.70
5 -47 -67 -60.4 1 20 13.40
5 -47 -67 -58.1 2 11.10
6 -37.7 -53.2 -46.1 2 15.5 8.40
7 -69.2 -74.3 -67 2 5.1 -2.20
8 -44.9 -63.1 -61.9 1 18.2 17.00
8 -44.9 -63.1 -54.2 2 9.30
9 -50.2 -60.5 -58.9 4 10.3 8.70
Average 13.44 7.94
Notes Min 5.10 -2.20
Sites 1-8 are 1-2 story suburban brick homes. Sites 1-8 are 1-2 story suburban brick homes. Sites 1-8 are 1-2 story suburban brick homes. Sites 1-8 are 1-2 story suburban brick homes. Max 20.00 17.00
2. Site 9 is a tall concrete apartment building. 2. Site 9 is a tall concrete apartment building. 2. Site 9 is a tall concrete apartment building. 2. Site 9 is a tall concrete apartment building. Std Dev 5.63 6.65
(10) Ibid, adapted from the original CRC Canada
report, including the addition of the last two
columns of analysis.
28
Terrain Blocking Mitigation

• Limit transmit power of personal/portable
  devices.
• At 26 dBm EIRP, the range of personal/portable
  devices to the co-channel D/U threshold is lt 1.4
  km on Ch 5-6, lt 900 m on higher frequency
  channels, i.e., less than the expected shadow
  footprint (see p.28).
• Using TPC reduces the interference range by
  reducing network aggregate transmitter power.
• Burst mode operation reduces the impact of
  transmissions to DTV operation relative to the
  assumption of continuous operation built into the
  D/U regulatory limits.
• Require all devices to include DFS/IPD
  capability, not just access points
• If all devices include DFS/IPD capability, the
  spectrum sensing footprint is increased, reducing
  the probability that an occupied channel will go
  undetected.
• Avoids the possibility of a shadowed master
  control device accidentally trying to set up the
  network co-channel with a TV broadcast incumbent.

29
Co-Channel Interference in Blocked Terrain
DTV Service Area
Terrain Shadow
Lb
Cognitive Radio Range to 23 dB D/U 668 m lt R lt1.4
km at 26 dBm EIRP
Edge of Service Contour
Shadow Depth (dB) Lb (km)
27 2.4
37 4.0
40 8.0
30
Analysis for Fixed Devices

• The following analyses establishes the
  performance limits of cognitive radio operation
  for fixed devices
• DFS sensitivity margin.
• Co-channel interference range margin.
• Terrain blocking footprint and issues.

31
DFS Sensitivity Margin Fixed Devices

• The sensitivity margin relative to the minimum
  in-service DTV field strength for a 30 ft high
  receive antenna is
• For Ch 6, margin 28 4 24 dB
• For Ch 13, margin 36 12 24 dB
• For Ch 51, margin 41 22 19 dB
• Table 6 (p.32) shows sensitivity margin
  calculations for various stations in the FCC
  database, using the FCC calculator at
  http//www.fcc.gov/mb/audio/bickel/curves.html.
• The DFS detector operating outdoors with an
  antenna height of 30 ft (9 m) can sense a TV
  channel outdoors at ranges gt 46 farther than the
  service contour (Table 6) in unobstructed terrain.

32
Table 6 DFS Sensitivity Margin Fixed Devices
          Service     DFS DFS
          Area Contour DFS DFS 11,12 Range Range
  DTV Band HAAT ERP Limit Range Limit Range Margin Margin
Station, Locale Ch (MHz) (m) (kW) (dBu) (km) (dBu) (km) (km) ()
WCFT-TV, Tuscaloosa, AL 5 76-82 625.4 9.5 28 128.7 3 190.0 61.3 47.6
KNSO, Merced, CA 5 76-82 575.0 11.0 28 126.5 3 189.8 63.3 50.0
KYES, Anchorage, AK 6 82-88 277.0 45.0 28 120.5 4 201.3 80.8 67.1
WEDY, New Haven, CT 6 82-88 88.0 0.4 28 56.0 4 89.3 33.3 59.5
KMBC-TV, Kansas City, MO 7 174-180 357.0 85.0 36 114.7 10 233.8 119.1 103.8
KNTV, San Jose, CA 12 204-210 376.6 103.1 36 118.2 11 233.8 115.6 97.8
WDAF-TV,Kansas City, MO 34 590-596 295.0 1000.0 41 96.2 21 164.3 68.1 70.8
KLCS, Los Angeles, CA 41 626-632 900.8 162.0 41 115.5 21 171.9 56.4 48.8
WMSY-TV, Marion, VA 42 638-644 448.0 100.0 41 89.8 21 136.5 46.7 52.0
KWDK, Tacoma, WA 42 638-644 695.0 144.0 41 107.0 22 156.7 49.7 46.4
WTVX, Fort Pierce, FL 50 686-692 438.3 704.0 41 106.0 22 166 60.0 56.6
KOPX, Oklahoma City, OK 50 686-692 483.0 200.0 41 97.8 22 146.3 48.5 49.6
KDTV, San Francisco, CA 51 692-698 701.0 476.3 41 118.5 22 177.3 58.8 49.6
11. The FCC calculator won't accept E field levels less than 10 dBu, so for channels 5, 6, 10 dBu was used for the calculation of range. 12. DFS Range assumes a 30 ft receiver antenna height for the fixed antenna.
33
Interference Range Margin Fixed Devices

• Table 7 shows the interference range margin for
  23 dB D/U, assuming 30 m base station antenna
  height and 9 m client antenna height.
• The interference range margin is 58 213 km (see
  p34).

Table 7 Interference Range Margin
          Range to   D/U
TV     D/U Required D/U limit DFS Range
Channel Center Freq E _at_ 1 m E limit Loss ITM Range Margin
  (MHz) (dBu) (dBu) (dB) (km) (km) (km)
6 85 140.8 5 135.8 31.2 89.3 58.1
12 207 140.8 13 127.8 20.6 233.8 213.2
51 695 140.8 18 122.8 14.3 177.3 163
34
Co-Channel Interference Range Margin
Limit of DFS Sensing Capability
DTV Service Area
89-234 km
Edge of Service Contour
Cognitive Radio Range to 23 dB D/U Limit
R lt 31 km (36 dBm EIRP)
35
Wrap Up

• Based on the proposed rules, the operational
  data, and the analysis presented herein,
  cognitive devices using spectrum sensing
  techniques can reliably operate in the TV band
  without causing interference to TV broadcast
  channels.
• The cognitive radio mode of operation is proposed
  as an addition to the rules for Part 15.244
  devices already proposed by the FCC in the TV
  Band NPRM.
• The application of cognitive radio technology to
  TV band unlicensed operation is an important step
  in realizing the full potential for a wide range
  of centralized and distributed networks utilizing
  otherwise unoccupied spectrum.

36
Acknowledgements

• The following organizations and individuals were
  immensely helpful in preparing this presentation
• The Berkeley Wireless Research Center, especially
• Professor Robert W. Brodersen
• Gary Kelson
• Danielja Cabric
• The Communications Research Centre Canada,
  especially
• Gerald Chouinard
• David Rogers
• Khalil Salehian
• Intel Corporation, especially
• Jeffrey Schiffer
• Alan E. Waltho

37
Acknowledgements

• Shared Spectrum Corporation, especially
• Mark McHenry
• William Byrnes
• Professor Adam Wolisz, Technische Universitat
  Berlin
• Michael Lynch, Nortel
• Denis Kuwahara, Boeing