Cognitive Radio Research at BT

1. Cognitive Radio Research at BT Dr Maziar Nekovee BT Innovate and Design & University College London maziar.nekovee@bt.com

2. Demand for mobile wireless communications But also • Home networks (e.g. HDTV streaming) • Smart metering • RFID • Machine-to-machine (e.g. intelligent transport systems) • Developing countries

3. Key resource: Radio Spectrum UK Industry paid over 20 billion pound for 140 MHz 3G spectrum

4. Who “owns” all the spectrum and why is it scarce?

5. 2004 0% 72% 2010 2004 6% 7% 2010 2004 94% 21% 2010 Solution 1: spectrum trading (Cave’s Report) Command & Control ZoneOfcom manages it Market Forces ZoneCompanies manage it Licence-exempt Zone Nobody manages it Approach that was adopted for about 94% of the spectrum Approach advocated by Cave and implemented by trading and liberalisation Approach currently adopted for 6% of spectrum, some argue for radical increase Source: William Webb, Ofcom

6. Solution 2: Opportunistic Spectrum Access Source: Yucek and Arsalan, IEEE Comm. Surveys and Tutorial, 2009

7. Cognitive RadioEnabling technology for OSA, …and much more Joseph Mitola III Cognitive Cycle

8. Cognitive Access to TV White Spaces: Spectrum Opportunity and Technology Challenges

9. What are TV White Spaces? • Cognitive radios can use channels {A1,A2,A3,B1,B2,B3,C1,C2,C3 • Provided they do not cause harmful interference to TV receivers within the coverage areas of A, B, C, and to wireless microphones (PMSE)

10. How much TVWS is there? • 256 MHz interleaved spectrum (total UK 3G spectrum 140 MHz!) • US auction of cleared TV spectrum raised $25 billion in 2008 • However, the availability varies strongly with location and trasmit power, but how exactly? Source: Ofcom Consultation on Cognitive Access, 9 February 2009

11. Quantifying TVWS availability in the UK cognitive device Total number of available channels for CR at location r

12. Regional variations in TVWS spectrum for cognitive access 0n average 150 MHz at any location in the UK Plymouth Southampton Cambridge 8 MHz/channels Brighton Thuriso Ipswich Newcastle Swansea Manchester Oxford Cardiff Liverpool Glasgow Birmingham Edinburgh Bristol London Leeds Source: Nekovee, Proc. IEEE ICC 2009

13. Source: Nekovee, Proc. IEEE ICC 2009

14. Spectrum identification/interference avoidance • Single-device detection • Sensing below thermal noise levels! • Cooperative detection • Certification difficult • Spectrum sensor nets • Security issues • Spectrum database • Favoured by FCC and Ofcom Microsoft, Google and BT • Wireless microphones are tricky • Requires location-awareness

15. Detecting DVBT signals below noise levels • Energy detection • Feature detection (increased complexity) • Autocorrelation • Cyclic prefix • Eigen value detection Source: Wang, Pervez, Nekovee, 2009

16. Potential applications: system-wide studies Home Networks Rural Broadband Bedroom 2 Den Bedroom 1 IEEE 802.22 standard Deck/Patio Mobile Broadband without 3G/4G? Kitchen Living Room CogNea Standard Broadband Internet Connection

17. Proposition A: Home Networks • Architecture • Point-to-Multipoint • Master-Slave HDTV HDTV data via TVWS • Queries TVWS database TVWS Set-top Box CogNea Standard (Philips, Samsung, BT) network BT Homehub mobile device device data via WiFi BT TVWS database 2. Provides available TVWS channels and power levels

18. Interference study, scenario modeled TVWS Spectrum in Central London • Square kilometre of central London • 40% houses (out of total 5000) selected with home hubs • Same service requirement 2 Mb/s, 6 Mb/s @ 12m range • With three interference loadings • Video-streaming only traffic profile – worst case scenario • Traffic profile mix of voice, video, data corresponding to 2 Mb/s • Traffic profile mix of voice, video, data corresponding to 6 Mb/s available channels Source: Kawade, Nekovee, IEEE DySPAN 2010 (submitted)

19. Technical assumptions for comparing various options • Other assumptions: • MAC layer overheads were assumed to be approximately 30% of the raw wireless link rate • No antenna scheme considered for TVWS band due to λ/2 restriction • however CogNeA (Philips, Samsung, Texas, HP) propose some antenna scheme/MIMO for laptops in higher UHF (in the other end of TVWS spectrum)

20. TVWS performance results (3/3) Outage clients (< 1 Mb/s) : 3% Service requirement 2 Mb/s: 97% Service requirement 6 Mb/s :50% Source: Kawade, Nekovee, IEEE DySPAN 2010 (submitted)

21. Nomadic/Mobile broadband with BT FON TV transmitter • Cooperative scheme for sharing home WiFi • Over 1 million BT FONs, and growing

22. Cognitive Radio: A longer term view

23. CR1 CR2 CR3 A quasi-continuum spectrum Now Future An elementary sub-channel Dynamic spectrum pooling based on user requirements, availability, and price Source: Nekovee, Proc. CrownCom 2008

24. Cognitive Spectrum Access Choose a spectrum band Click on the item below to connect to BT Network via one of the available spectrum bands Refresh spectrum list Setup an automated spectrum manager TV White Spaces free of charge (cognitive only) Radar spectrum free of charge (cognitive only) Learn about cognitive spectrum access 3G Spectrum Vodafone Change the order of preferred spectrum £0.0012 per second (licensed or cognitive only) Change advanced settings ISM bands free of charge (best effort) 2G Spectrum Orange £0.0005 per second (licensed or cognitive only) 3G Spectrum 3 £0.0014 per second (licensed or cognitive only) Spectrum portfolio

25. Our research interests/activities • Technologies and models • System-wide issues: multi-user access (etiquette), capacity and coverage, QoS and mobility • Agile modulation (NC-OFDM) and channel bundling techniques • Cognitive radio testbed and trials • Sensing, antenna arrays and MIMO for cognitive access • Cognitive radio +optical communication? • Spectrum micro auctions • Spectrum databases • Application Scenarios • Future home networks • Mobile/nomadic broadband • Smart metering • Cognitive Femtocells • Cognitive radio in vehicles • Collaborations • 2 large FP7 projects (starts Jan 2010) • Microsoft, Google, BBC, CogNea • Scottish Universities • Open to exploring new ones!

26. In press