An overview of how dynamic spectrum access enables the latest generation of Wi-Fi (IEEE 802.11af ) to achieve greater coverage and capacity

1. Dynamic spectrum and the
race for mobile capacity
29th October 2014
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2. (c) Larkhill Consultancy Limited 2014
Agenda
• Increasing role for licence exempt spectrum sharing
in serving the growing mobile data demand
• Importance of lower frequencies – significance of
TV white spaces and dynamic spectrum access
• What the arrival of 802.11af and triple band access
points will mean for Wi-Fi

3. Anytime, anywhere on a mobile
device …..
• Mobile devices are becoming the
dominant means of access to a
growing host of online services
• Tablets and smartphones have
broadened Internet use
• As services use higher quality
images & video, wireless network
capacity needs to rise….
• Spectrum is a key input …
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4. Capacity is important but there
are other factors
Wireless access networks
WAN + LAN
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Broadband
Internet of
Things
Capacity
Coverage
Flexibility
Resilience

5. Spectrum availability is critical to
meeting expectations for wireless
.47-.79 GHz .8 .9 1.8 2.1 2.4 2.6
GSM
GSM
3G
LTE
Wi-FI
LTE
• Access to spectrum is key to extracting value from wireless technology
• Harmonised access enables economies of scale in equipment
• Wider bands enable greater performance – affecting the dimensioning of networks
• Lower frequencies enable better coverage
• Future networks need to straddle multiple bands to deliver the best possible connectivity
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to users wherever they are
Frequency
1GHz 2GHz 3.5GHz
TV
+
802.11af
Radio
200 MHz 600 THz

6. Licence exempt access is now a key
tool in meeting mobile demand
• Licence exempt networks have taken an
increasing share of mobile data traffic
• Licence exemption (LE) is a powerful tool for
wireless innovation
• It enables flexible, ad-hoc and device-to-device
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direct links
• Until now, LE has been confined to short
range applications & higher frequencies
• Dynamic spectrum access technology allows
higher transmission power according to
location & safe sharing with licensed users
Source: TCS-Sensor Lab
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7. Wi-Fi family tree
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802.11b
11 Mbps , 20 MHz DSSS,
Band : 2.4 GHz
802.11a
54 Mbps, 20 MHz OFDM
Band : 5 GHz
802.11g
54 Mbps, 20 MHz OFDM
Band : 2.4 GHz
802.11n
600 Mbps, 20/40 MHz, OFDM + MIMO
Bands: 2.4 or 5 GHz
802.11af
600 Mbps
Band: TVWS
802.11ac
1.3 Gbps
Band: 5 GHz
802.11ad
6 Gbps
Band: 60 GHZ
WiGig
.47-.79
(UHF)
2.4
GHz
5 GHz 60
Frequency (GHz)
.47-.79
(UHF)
2.4
GHz
5 GHz 60
Frequency (GHz)
.47-.79
(UHF)
2.4
GHz
5 GHz 60
Frequency (GHz)
.47-.79
(UHF)
2.4
GHz
5 GHz 60
Frequency (GHz)
Source: Mediatek, Larkhill analysis

8. 5 GHz is good for adding capacity
Band Capacity
(MHz)
Status
5150 to 5250 MHz 100 the “new global band”
5250 to 5350 MHz 100 OK in many regulatory domains
5350 to 5470 MHz ? problematic everywhere
5470 to 5725 MHz 255 OK in EU; radars limit its use
elsewhere
5725 to 5825 MHz 100 OK in EU, but limited to 25 mW
5825 to 5925 MHz EU plans to share with road
tolling
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Source: Mediatek, Larkhill analysis

9. 60 GHz – massive additional
licence-exempt capacity
• Opportunity to deploy
large additional Wi-Fi
capacity
• Fits well with urban
environments where user
density is high and fibre
access is widely available
• In-room networks
• Point to point links for
backhaul (line of sight)
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10. Adding more sub-5 GHz capacity
depends on more efficient sharing
• Although spectrum is fully allocated,
much is left unused – geographically
and temporally
• Dynamic spectrum access uses new
technology to enable opportunistic,
licence-exempt access
• This provides a great opportunity to
boost the coverage and capacity that
Wi-Fi networks can enable
• The Dynamic Spectrum Alliance is
taking the technology around the world
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OK, you can use
channels x, y, z
Geolocation
database
My
device
I’m in
Glasgow
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11. Lower frequencies help fill coverage
gaps and enhance capacity
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Source: BT R&D
Simulation of coverage
with 20% access point
penetration, in a 1 km2
dense urban area in
Fulham, London
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Wi-Fi , 5 GHz Wi-Fi , 2.4 GHz TV White Spaces – 600 MHz

12. TV white spaces - global opportunity
to access lower frequencies
• UHF frequencies have bee allocated for TV
broadcasting (470-790 MHz in EU)
• Unused gaps in these bands are called TV
white spaces (TVWS)
• New Dynamic spectrum access technology
protects TV reception whilst releasing
valuable new capacity for licence-exempt
use
• Already commercialised in the US, pilot
deployments are underway across the rest
of the world, as regulators prepare enabling
frameworks
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Image source: Ofcom

13. Dynamic Spectrum Access can enable a
full range of business models
Facilitates centralised
infrastructure investment
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Scope for innovation
Coexistence of multiple
users/applications
Can protect services
against effects of interference
Enables infrastructure
investment by end users
Wi-Fi LTE
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14. IEEE 802.11af adds TV white
spaces to the Wi-Fi band family
• First wireless LAN standard using geo-location
databases for access to spectrum
• IETF PAWS will be the predominant interface
• Adapted from state-of-the-art 802.11ac PHY
• 6,7 or 8 MHz TV channels for global applicability
• < 35 Mbit/s per TV channel (8 MHz)
• < 560 Mbps with 4 TV channels bonded and 4
spatial paths
• Enterprise management of database access
• Using a Registered Location Secure Server
• Maintains a local copy of local white space map
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8 8 8 8
14
8
Total: 8 MHz
8 8
8 8
Total: 16 MHz
8 8 8 8
Total: 32 MHz
802.11af
channel configurations

15. Three bands improve scalability of
Wi-Fi coverage
10-20 metres
Kilometres
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TV White
Spaces
5 GHz 2.4 GHz
Tens of metres

16. Triple-band Wi-Fi set to become
the new norm
• Adding 802.11 af to standard Wi-Fi
brings TV white spaces coverage
and capacity
• New triple band Wi-Fi will help
improve coverage and capacity, in
urban and rural locations
• First prototypes were tested in the
Glasgow White Spaces Pilot in June
2014
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17. (c) Larkhill Consultancy Limited 2014
Summary
• Increasing personal connectivity is driving
demand for more capacity and better coverage
• Spectrum clearance is too slow, so dynamic
spectrum access (DSA) technology enables
faster access to extra capacity
• DSA will revolutionise spectrum access &
management
• 3. Initially, enabling the TV white spaces to fill
coverage gaps as well as adding valuable
capacity, using the new 802.11af standard
• Providing a foundation for other bands to be
added over time (3.5 GHz is currently under
discussion in the US)
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Source: Microsoft

18. (c) Larkhill Consultancy Limited 2014
Thank you
• Contact:
Andrew@larkhillconsult.co.uk
About Larkhill
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19. Further reading
• Background material and information about pilots
etc. Dynamic Spectrum Alliance
• The Centre for White Space Communications
(University of Strathclyde)
• Microsoft dynamic spectrum access pilots
• White spaces applications in Singapore
• Airties: 802.11ac is not sufficient
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