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TV White Space:Reusing old spectrum in
innovative ways
Pasquale Cataldi
TV White SpaceReusing old spectrum in
innovative waysNetworkshop44 - 22 March 2016
@P_Cataldi - #TVWS
Pasquale Cataldi
Outline1. About Nominet2. TV White Spaces• What it is• How it works• Use cases
3. The Oxford Flood Network4. Conclusion
#nws44 #TVWS4
About NominetNominet has run the .uk internet domain since 1996, managing a key part of the internet infrastructure
10 million internet domains on .uk registry, handling between 4 – 5 billion DNS requests per day
Private not-for-profit company run for public benefit
#nws44 #TVWS5
Nominet R&DInvestigating emerging technologies that may have a impact on the Internet
Applied research groupExpertise across a wide range of topicsWork and partner with all types of organisations globallyActive contributors to internet standards
#nws44 #TVWS6
Spectrum is a finite (and valuable) resource
Demand for spectrum over the next decade will outstrip supply
We can manage it more intelligently
and meet the demand
A win for governments,
businesses and consumers
The UK frequency allocation table
…an empty box of chocolate
#nws44 #TVWS7
TV white spacesTV white spaces are frequencies made available following the analogue to digital switch over
#nws44 #TVWS8
•Line-of-sight not required•Up to 10 Km outdoor•Enhance indoor connectivity
Superior propagation characteristics
•ADSL-comparable performance•Carrier grade radiosGreat performance
•No operator required•No need for complex infrastructure (like 3G/4G)
Competitive cost
Sharing TV bandDTT broadcasters (and wireless microphones, PMSE) operate in this spectrum and have priority
TVWS access for other uses needs to be managed carefully to protect priority users
TVWS is the ideal test-bed for smart spectrum management
#nws44 #TVWS9
Accessing the available spectrumGeo-Location Database (WSDB) “Ask” before transmittingSpectrum Sensing “Sense” before transmitting
It is easier to implement a database approach1. No hidden-terminal problem2. Easier to manage spectrum and enforce
policies3. Complexity in the cloud, not on the radios
#nws44 #TVWS10
Ofcom regulatory framework
List of qualified WSDBs
TVWS availability maps for protection
of DTT
Details of PMSE assignments
Whitespace Database(s)
Master deviceSlave device
TV Band
WSDBs get updates about DTT and PMSE from OfcomUpon request from a master device, a WSDB computes the maximum transmission power per channelEvery 15 minutes masters must contact the WSDB to continue to transmit
Whitespace Database(s)WSDBs
#nws44 #TVWS11
Radios and WSDBs need to speak the same languageThe more databases radios can talk to, the betterWSDBs want to make sure that they can interface with as many radios as possible
PAWS standard
The actual implementation of the protocol might change among different countriesAlthough developed for TVWS, PAWS could be used for other portions of the spectrum
#nws44 #TVWS12
TV white spaces have multiple uses Rural
broadband Super Wi-Fi
Emergency communications
Internet of Things Community networks
#nws44 #TVWS13
The Oxford Flood Network
https://www.youtube.com/v/OWcx4lQy5UI
14 #nws44 #TVWS
Getting data from some sensors to the Internet was challenging1. There is no internet access in the park2. 3G connection is flaky (and not free)3. Directive LOS solutions would not work
Solving a connectivity problem
#nws44 #TVWS15
Our solution exploited multiple technologies1. Sensors are connected to a hub through 868MHz
radio modules2. The hub is connected to the internet through a
TVWS link (point-to-point)• Slave device close to the sensors• Master connected to the internet
3. We now also provide Wi-Fi connectivity to Hogacre Common
Master location – Speedwell House
For the master location we initially selected Speedwell House
1. High building
2. Central location
3. County Council building
4. ~890 metres from slaveHowever, Speedwell House is not a good location
BT building in proximity of the master created too much interference
BT building
Speedwell(master + antenna)
Hogacre Eco Park(slave + antenna)
#nws44 #TVWS16
Master location - Chilswell RoadWe decided to move the master to a more suitable location to avoid the source of interference1. Residential property on Chilswell Road2. ~470 metres from slave
We could establish the link without problems
>16Mbps aggregated throughput
#nws44 #TVWS17
Lessons learned from the Oxford Flood Network
Areas poorly connected to the internet can greatly benefit from the use of TVWS
Information from both WSDB and in-field measurements is necessary to optimally plan and deploy a TVWS network
TVWS radios configuration might not be very user-friendly… like most radio devices, unfortunately
#nws44 #TVWS18
Conclusion
#nws44 #TVWS19
Spectrum management needs to become much smarter than it is nowadays Efficient spectrum sharing will undoubtedly happen in the future
TVWS is an interesting technology to elegantly solve connectivity problems Great radio propagation characteristics at competitive cost Channel availability is not guaranteed - depends on location and time
Awareness about TVWS needs to increase in the UK We do not expect a fast take-off in the adoption of this technology Applications will initially focus on alleviating the digital divide
If you want to know more about TVWS opportunities, or deploy a TVWS network, come talk to us!
Q&ATVWS – It’s just the beginning
Website nominet.ukEmail Pasquale.Cataldi@n
ominet.ukTwitter @P_Cataldi -
@NominetR&D blog nominet.uk/
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