1. Geo-location Database Issues of Ofcom
March 2008
doc.: IEEE /0437r1
Nov. 2011
Geo-location Database Issues of Ofcom
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Donghun Lee, et al, ETRI
Peter Ecclesine, Cisco Systems

2. March 2008
doc.: IEEE /0437r1
Nov. 2011
Abstract
This material summarizes geo-location database issues for Ofcom
Especially, the key issues to be addressed in developing a geo-location approach are given as follows:
Database topology
Database information from WSDs
Database information to WSDs
Database update frequency
Database architecture
Donghun Lee, et al, ETRI
Peter Ecclesine, Cisco Systems

3. Abbreviations and acronyms
Nov. 2011
Abbreviations and acronyms
WSD : White Space Devices
PMSE : Program Making and Special Events
DTT: Digital Terrestrial Television
Donghun Lee, et al, ETRI

4. TV White Space Database Activities (Ofcom)
Nov. 2011
TV White Space Database Activities (Ofcom)
Ofcom, the regulatory body in UK started the consideration of TV white space in 2007
13th Dec – In “Digital Dividend Review: A statement on our approach”, Ofcom considered the use of interleaved spectrum by license exempt devices
16th Feb – In “Digital Dividend: Cognitive Access. Consultation on license exempting cognitive devices using interleaved spectrum”, Ofcom consulted on sensing threshold levels for using sensing alone
1st July 2009 – In “Digital Dividend: Cognitive Access. Statement on license-exempting cognitive WSDs using interleaved spectrum”, Ofcom considered 3 different mechanisms for finding the frequency of operation
[1] 17th Nov “Digital Dividend: Geo-location for Cognitive Access. A discussion on using geo-location to enable license-exempt access to the interleaved spectrum”, Ofcom requested the views of the stakeholder in TV white space business
[2] Nov – “Implementing Geo-location”, Ofcom received supportive feedback on the geo-location mechanism and received useful suggestion for improvement and flexibility
1st Sep – “Implementing Geo-location: Summary of consultation responses and next steps”
Donghun Lee, et al, ETRI

5. Key issues of geo-location database
Nov. 2011
Key issues of geo-location database
Key issues to be addressed in developing a geo-location approach are given as follows:
Database topology
Database information from WSDs
Database information to WSDs
Database update frequency
Database architecture
Donghun Lee, et al, ETRI

6. Database topology (Ofcom)
Nov. 2011
Database topology (Ofcom)
Should both closed and open approaches be allowed?
Both can exist in parallel with some manufactures directing their devices to an “open” database and others delivering a “closed” database [1]
Some responders, however, argued for flexibility with any arrangement of closed and open databases being allowed to co-exist [2]
Some suggested that there must be at least on open database to ensure that all devices could operate but that multiple open databases should be encouraged [2]
Others noticed that closed databases could cause consumer concern, particularly if shut down [2]
Donghun Lee, et al, ETRI

7. Database information from WSDs (Ofcom)
Nov. 2011
Database information from WSDs (Ofcom)
WSDs provide the following information to database as a minimum requirement [2]
Its location provided in terms of a latitude-longitude position
Its determination as to the accuracy of that location to a 95% certainty provided in meters
Its model type provided in terms of manufacturer and model number
Its height above ground level if it is a fixed terminal mounted on a mast or similar
Donghun Lee, et al, ETRI

8. Database information to WSDs (Ofcom)
Nov. 2011
Database information to WSDs (Ofcom)
The following information needs to be provided by the geo-location database to the WSDs [2] :
The start and stop frequency for the channel
The allowed power level for using the channel
The channel validity time
The time that the device is allowed to use the channel before having to re-check with the database
Whether sensing is requiring in addition to geo-location
This requirement is not proposed to be used in the UK but included to aid international harmonization
If sensing is needed then the sensing level in dBm and the type of primary usage (i.e., DTT) will also be provided
Donghun Lee, et al, ETRI

9. Database update frequency (Ofcom)
Nov. 2011
Database update frequency (Ofcom)
A key issue in implementing a geo-location database is the frequency with which the database should be updated [1][2]
The manufacturers of cognitive devices have previously suggested that an update period of 24 hours would be helpful [1].
PMSE licensed users suggest that time between a frequency being requested and its being required can be as little as two hours [1]
An alternative is flexible approach, as like [1]
Initially, this might always be set to a short time period such as two hours.
However, if over time it became clear that a longer time period would provide sufficient protection for licensed users, this could be changed
The report in [2] stated that two-hourly updating was generally the right balance but some pointed out that if time validity is provided then a general update frequency is not needed
Donghun Lee, et al, ETRI

10. Database architecture (Ofcom)
Nov. 2011
Database architecture (Ofcom)
The diagram in next slide provides an overview of how geo-location database works [2]
1) The master WSD contacts a website maintained by Ofcom or similar body
2) Ofcom server provides a list of the geo-location database
3) The master WSD then decides which of these geo-location database it wishes to consult and send to its information
4) The database provide by way of a response a set of available frequencies in the master device’s area
5) A master WSD can then signal allowed frequencies and power levels to any slave devices on its selected channels
6) The slave responses with confirmation or data
Donghun Lee, et al, ETRI

11. Database architecture (Ofcom)
Nov. 2011
Database architecture (Ofcom)
Donghun Lee, et al, ETRI