Tim Brown discusses spectrum efficiency from technical, business, and regulatory perspectives. Technically, spectrum efficiency can be improved through technologies like MIMO that allow more channels. Business innovations like WiFi hotspots have led to 2000x growth in capacity. Regulators are exploring unused "white spaces" to allow flexible use. The combined efforts across these areas can help address the growing global demand for mobile data traffic and spectrum.

1. Defining Spectrum Efficiency
Tim Brown, Professor
Innovation Africa Digital Summit
Banjul, The Gambia
March 27, 2014
World-Renown Faculty | Collaborative Learning | Innovation Solutions | Students Employers Hire
www.cmu.edu/rwanda

2. 2
Master’s Programs
• M.S. in Information Technology
• M.S. in Electrical & Computer Engineering
Accepting applications for August 2014
innovation, global perspective,
on campus, hands-on skills
CMU Graduate Programs in Rwanda

3. Spectrum
Low HighRadio Frequencies

4. Demand on Spectrum is Growing
Five year projected growth in mobile data traffic
• FCC: “The broadband spectrum deficit is likely
to approach 300 MHz by 2014”
• Cisco VNI: A smartphone generates 29X traffic
of a feature phone.
World
Middle East
and Africa
Ericsson (to 2019) 10X 11X
Cisco VNI (to 2018) 11X 14X

5. What is Spectrum Efficiency?

6. Spectrum Efficiency - Technical
http://commons.wikimedia.org/wiki/File:Radio-tower-autobahn-tree.jpg http://en.wikipedia.org/wiki/File:Two_Cell_Phones_2.png
Fundamental Limits
For more users need to be
• Louder

7. Spectrum Efficiency - Technical
• MIMO: More channels

8. Spectrum Efficiency - Technical
Technical  25 times growth in capacity
Past 50 years

9. Spectrum Efficiency - Business

10. 300x growth in 27 years
$365B total investment

11. Spectrum Efficiency – Business
Changing the model
• BT Wi-Fi > 5 million hotspots in UK
 500,000 in London
 17 sq. km WMAN central London
 Part of FON Consortium’s > 8 million hotspots
• Free Mobile (France) > 4 million hotspots
 Built on wireline subs of parent, Iliad
• China Mobile > 2 million
 Projecting 70% offload rates
• U.S. Cable Consortium (5 companies)
 200,000 hotspots (mostly outdoors/urban)
 Comcast: Adopting FON model ~ potential 20 million hotspots

12. Spectrum Efficiency - Business
Business 2000 times growth in capacity
Past 30 years

13. Spectrum Efficiency - Regulatory
Unused “white spaces”
All spectrum is
allocated

14. Spectrum Efficiency – Regulatory
Most Spectrum is Unused

15. Spectrum Efficiency - Regulatory
• Most spectrum is unused – even in cities

16. 17
• ITU Region 1 is diverse
– Conform  waste spectrum
– Differ  miss future innovation
Cognitive (aka white space) radios.
ITU Region 1
Spectrum Efficiency - Regulatory

17. Spectrum Efficiency – Regulatory
White-Space Radios
• Idea: Logical overlay on existing radios
– radios get permission (a policy) to communicate
– Regulator through policies controls
who, what, where, and when
– Polices timeout and need renewed.
• Frees up spectrum – local and flexible
FAA
10MHz
CONUS
NTIA

18. Spectrum Efficiency - Regulatory
Regulatory 25times growth in capacity
Past 40 years

19. Conclusion
• Exploding use of spectrum
• Requires combined efforts in
– Technolgy
– Business
– Regulation