1. October 2010
On the new FCC second order memorandum opinion and order with regard to TVWS
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Yohannes Alemseged, NICT
Yohannes Alemseged, NICT

2. October 2010
Summary
This document highlights the new rules of FCC on TVWS released on Sept 23, 2010, FCC that replaced the release of FCC document on Nov 14, 2008, FCC
Sentences are rephrased using key words to fit into the slide
italic phrases indicate our interpretations
For further clarification please refer to the final rule page of FCC document, FCC
Yohannes Alemseged, NICT

3. October 2010
A set of definitions
Available channel: A 6MHz channel which is not used by an authorized service.
Authorized service = Incumbent service
Operating channel: An available channel used by TVBD.
Operating channel according to FCC is specified per 6 MHz
Yohannes Alemseged, NICT

4. October 2010
A set of definitions
Sensing only device: A personal/portable TVBD that uses spectrum sensing to determine a list of available channels. Sensing only devices may transmit on any available channels in the frequency bands MHz (21-36) and MHz (38-51).
Spectrum sensing: A process to detect whether the channel is occupied by a radio signal/s from authorized services.
Personal /portable device: A TVBD that operates (transmit/receive) at unspecified locations that may change. Operating frequency (ch 21-36, 38-51)
Portability clearly includes mobility
Yohannes Alemseged, NICT

5. October 2010
Fixed device
Operates at a specified fixed location, may select channels for operation itself from a list of available channels, initiate and operate a network by sending enabling signal to one or more fixed TVBDs or personal portable TVBDs.
Yohannes Alemseged, NICT

6. Contact Verification Signal
October 2010
Contact Verification Signal
An encoded signal broadcast by a fixed or mode II device for reception by Mode I device.
Signal is encoded to ensure the signal originates from the device that provided the list of available channels.
A fixed or mode II device shall provide the information needed by a Mode I device to decode the contact verification signal at the same time it provides the list of available channels.
Yohannes Alemseged, NICT

7. Mode II personal/portable device
October 2010
Mode II personal/portable device
Uses internal geo-location capability and access TV bands database
Connection to data base can be directly or indirectly (through a fixed device or mode II device)
A mode II device may select a channel itself and initiate a network and operate as part of a network of TVBDs
A mode II device may provide its list of available channels to a mode I personal/portable device for operation by the mode I device.
Yohannes Alemseged, NICT

8. October 2010
Network initiation
The process by which a fixed or Mode II TVBD sends control signals to one or more fixed TVBDs or personal/portable TVBDs and allows them to begin communications.
Relation ship between the terms, Control signal, Contact
verification signal, Enabling signal to be explored/clarified.
Yohannes Alemseged, NICT

9. Permissible channels of operation
October 2010
Permissible channels of operation
All TVBDs are permitted to operate available channels in the frequency bands MHz (ch 21-36), MHz (ch 38-51).
Operation of TVBDs is prohibited on the first channel above and the first channel below TV channel 37 that are available (not occupied by authorized service)
Ch 36 and Ch 38 can not be used at any time by TVBDs (they will be either occupied or prohibited from use when not occupied)
If two channels, one each side of ch 37, not available, operation is prohibited on the first two channels nearest to ch 37 (this will be indicated on the TV bands database)
Operation on available channels 54-60MHz (ch 2), MHz (ch 5- 6), MHz (ch 7-13) and MHz (ch 14-20) is permitted only for fixed TVBDs that communicate with other fixed TVBDs.
Yohannes Alemseged, NICT

10. October 2010
Sensing only device
A personal/portable TVBD that uses spectrum sensing to determine a list of available channels.
Sensing only devices may transmit on any available channels in the bands MHz (ch 21-36) and MHz (ch 38-51)
ch 36 and ch 38 couldn’t be used, hence no sensing is needed in these channels. Sensing should include always microphone signals since the 2 channels to be allocated by the database will not be known by the sensing only devices
Yohannes Alemseged, NICT

11. October 2010
Power constraint
For fixed TVBD – maximum power delivered to the antenna 1W
If direction antenna >6dBi used, the amount that exceeds 6dBi shall be reduced from the input
Personal/portable TVBDs, max EIRP shall not exceed 100mW (20dBm), or 40mW (16dBm) when there is adjacent channel requirement
Transmit Power Control is mandatory
Yohannes Alemseged, NICT

12. Power constraint Power spectral density over 100kHz
October 2010
Power constraint
Power spectral density over 100kHz
Fixed device: 12.2 dBm
Personal/Portable device with adjacent channel requirement: -1.8dBm
Sensing-only devices: -0.8dBm
All other Personal/Portable (mode I and mode II): 2.2dBm
Yohannes Alemseged, NICT

13. October 2010
Antenna
All transmit and receive antennas of personal/portable device shall be permanently attached
Fixed devices may not have antenna more than 30m, devices may not be installed at HAAT 76 meter
Yohannes Alemseged, NICT

14. Interference avoidance methods
October 2010
Interference avoidance methods
A TVBD shall rely on the geo-location and database access mechanism to identify available channels
Yohannes Alemseged, NICT

15. October 2010
Emission limits
Permissible power emission in a TV channel adjacent to a TVBD operation channel be 72.8 dB bellow the highest average power in the operational channel.
Emission measurement in the operational channel is performed using a resolution bandwidth of 6MHz but in the adjacent channel with a resolution bandwidth of 100KHz.
Yohannes Alemseged, NICT

16. Geo-location and database access requirements
October 2010
Geo-location and database access requirements
Geographic coordinates of a fixed TVBD shall be determined to an accuracy of +/-50 meters. The geographic coordinates of a fixed TVBD shall be determined at the time of installation and first activation from a power-off condition.
Mode II devices shall check its location at least once every 60 seconds while in operation.
Fixed device shall check data base at least once in a day
Fixed devices must adjust their use of channel and schedule for 48 hours after checking the database
Yohannes Alemseged, NICT

17. Geo-location and database access requirements
October 2010
Geo-location and database access requirements
Mode II device must access database each time it is activated from a power-off
Mode II device must re-check its location and the database if it changes its location by more than 100 meters from the location at which it last accessed the database
Mode II in a powered state shall recheck its location and access database daily
Yohannes Alemseged, NICT

18. Geo-location and database access requirements
October 2010
Geo-location and database access requirements
A mode II device may load channel availability information for multiple locations around, in the vicinity of its current location and use that information for its operation.
it can use such information to define a geographic area within which it can operate on the same available channel (coverage area)…it can also operate on mobile basis with in that area
Yohannes Alemseged, NICT

19. Geo-location and database access requirements
October 2010
Geo-location and database access requirements
If fixed or Mode II devices fail to contact, they may continue to operate until 11:59 next day
A mode I device must receive contact verification signal /contact mode II fixed device that provided the channel least at least every 60 seconds (exception when the mode I device is on sleep mode)
A mode II device must re-check/reestablish contact with a fixed or Mode II device to obtain channel list if they lose power.
If a Mode II device loses power and obtains new channel list, it must signal all mode I devices the new channel list
Yohannes Alemseged, NICT

20. Geo-location and database access requirements
October 2010
Geo-location and database access requirements
Device manufacturers may implement a system that pushes updated channel availability from the database
TV bands database must provide lists of available channels only to certified TVBDs
To achieve the above two, TV bands database administrators shall obtain a list of certified TVBDs fro the FCC Equipment Authorization System
Yohannes Alemseged, NICT

21. Geo-location and database access requirements
October 2010
Geo-location and database access requirements
Display of available channels: TVBD must incorporate capability to display list of identified available channels and its operating channels: Note that these channels (each) occupy 6MHz according to the definition.
Identifying information: Fixed TVBDs shall transmit identifying information that conforms to a standard (?). Identification signal includes geographic coordinates.
Yohannes Alemseged, NICT

22. October 2010
Security
Security: TVBDs shall incorporate security measures to ensure they are only capable of contacting database operated by FCC designated administrators.
Application for certification of TVBDs are to include high level operational description of security mechanisms
Mode II and Fixed devices should identify at least one TV bands database that the device will access for channel availability and the security conformance used by the database.
Yohannes Alemseged, NICT

23. October 2010
TV bands database
Must indicate channel availability information including a scheduled changes over the course of 48 hrs period.
Must verify that the FCC identifier of a device seeking access to its service valid. This includes verification of the FCC identifier of Mode I device provided by the fixed or mode II device.
Yohannes Alemseged, NICT

24. October 2010
TV bands database
TVBD registration in the database for fixed TVBDs include devices antenna height above ground level (HAAT is computed by special software at the database)
Yohannes Alemseged, NICT

25. No major change for sensing only devices (50mW)
October 2010
No major change for sensing only devices (50mW)
Detection threshold = -114dBm /6MHz, for NTSC signals per 100KHz, for microphone dBm/200KHz
Channel availability check time = 30s
In-service monitoring = 60s
Channel move time=2s
Yohannes Alemseged, NICT