1. Spectrum Agile Radio: Opportunistic Usage of Radio Spectrum Dr.-Ing. Stefan Mangold Philips Research USA stefan.mangold@philips.com stefan.mangold@philips.com

2. 2 / 27 Cognition Webster’s –to become acquainted with, to know, to come to know –the act or process of knowing including awareness and judgment Britannica –mental process described as an experience of knowing –including recognizing, and reasoning we use “agile radio” as synonym for “cognitive radio”: cognitive radio = agile radio, including smart algorithms* *) algorithms that consider effects on other, competing radio systems

3. stefan.mangold@philips.com 3 / 27 Outline Existing standards and limitations –IEEE 802.11 wireless LAN –Ultra Wideband wireless PAN Agile radio solution –New trends in wireless –Solution, benefits –Architecture Spectrum opportunity identification –Spectrum usage patterns –IEEE 802.11k radio resource measurement Spectrum opportunity management –Horizontal sharing: protection of other agile radios –Spectrum etiquette and cognitive behavior Conclusion

4. stefan.mangold@philips.com 4 / 27 IEEE 802.11 spectrum usage “Unlicensed” spectrum 2.4GHz, 5GHz (figure not to scale) Limited frequencies Open access (FCC Part 15)

5. stefan.mangold@philips.com 5 / 27 Problem with IEEE 802.11 The unlicensed bands are filling up ! unlicensed spectrum, heavily used (4 channels, 20 MHz each) unlicensed (4 channels)

6. stefan.mangold@philips.com 6 / 27 Limitations of IEEE 802.11 Promised throughput: e.g. 200 Mb/s (11n) –PHY throughput at ideal conditions – an academic number Throughput will drop in real-life –suffers from legacy 802.11a/g interference – the unlicensed bands are already occupied –high throughput transmission is only optional –radio resources (system capacity) is shared More realistic expectation: ~ ½ · 200 Mb/s –operation in unlicensed bands Major radio regulatory constraint: regulation does not permit more frequencies

7. stefan.mangold@philips.com 7 / 27 Ultra Wideband spectrum usage “Underlay” sharing with primary radio systems (figure not to scale) here: multi-carrier transmission (MBOA) operation at large spectrum small transmission powers

8. stefan.mangold@philips.com 8 / 27 Obvious problem with Ultra Wideband Coverage (transmission range) is very limited !

9. stefan.mangold@philips.com 9 / 27 Limitations of Ultra Wideband Promised throughput: 480 Mb/s @ distance <10m –PHY throughput at ideal conditions –an academic number Throughput will drop in real-life –Ultra Wideband re-uses frequencies that are already in use: interference –high throughput transmission is only optional, mandatory for the radio devices are only lower transmission rates –radio resources (system capacity) are shared More realistic expectation: ~ ½ · 480 Mb/s –shared by all devices, and with licensed primaries (incumbents) Major radio regulatory constraint: regulation does not permit higher transmission power

10. stefan.mangold@philips.com 10 / 27 Takeaway … IEEE 802.11 –available spectrum is constrained by radio regulation Ultra Wideband –transmission power is constrained by radio regulation

11. stefan.mangold@philips.com 11 / 27 Outline Existing standards and limitations –IEEE 802.11 wireless LAN –Ultra Wideband wireless PAN Agile radio solution –New trends in wireless –Solution, benefits –Architecture Spectrum opportunity identification –Spectrum usage patterns –IEEE 802.11k radio resource measurement Spectrum opportunity management –Horizontal sharing: protection of other agile radios –Spectrum etiquette and cognitive behavior Conclusion

12. stefan.mangold@philips.com 12 / 27 Trends in wireless Rapid growth of wireless services over past years –Unlicensed (WLAN/WPAN) and licensed (cellular) bands –Growing demand for wireless communication services Access to spectrum is frustratingly difficult –Unlicensed bands are filling up –Licensing process complicated, slow, expensive In contrast, in measurements only 10% of the spectrum is in use at all –even in densely populated areas Conclusion: –There may be enough spectrum, usage is just not permitted –The existing regulatory regime leaves room for improvement Agile radios attempt to solve this problem !

13. stefan.mangold@philips.com 13 / 27 (Spectrum) agile radio solution Agile radio takes the best of both worlds –IEEE 802.11 dynamic channel selection for using the optimal frequencies –Ultra Wideband paradigm for re-usage of licensed spectrum Agile radios use the licensed spectrum “opportunistically” Agile radios decide on their own about spectrum usage –eased regulatory constraints –vertical spectrum sharing to protect incumbents –horizontal spectrum sharing for example with spectrum etiquette Agile radios can benefit from the DARPA XG framework –to protect incumbent, licensed radio systems –to allow flexible radio regulation True “cognitive” agile radio may include “reasoners” –Allows new types of algorithms based on first-order predicate logic

14. stefan.mangold@philips.com 14 / 27 It extends existing standards Underlay  overlay sharing of “white space” 2

15. stefan.mangold@philips.com 15 / 27 Benefits Capacity beyond IEEE 802.11 and Ultra Wideband –This is an extra benefit consumers will like Wireless communication over larger distances –Including IEEE 802.16 / 802.22 –Broadband access, incl. mobility support, as extension to known standards Immediate regulatory approval for different countries –Connected planet Proactive radios – transparent to consumers –Cognition (awareness, adaptation) in resource management –Cognition (awareness, adaptation) in services and applications

16. stefan.mangold@philips.com 16 / 27 Architecture

17. stefan.mangold@philips.com 17 / 27 Outline Existing standards and limitations –IEEE 802.11 wireless LAN –Ultra Wideband wireless PAN Agile radio solution –New trends in wireless –Solution, benefits –Architecture Spectrum opportunity identification –Spectrum usage patterns –IEEE 802.11k radio resource measurement Spectrum opportunity management –Horizontal sharing: protection of other agile radios –Spectrum etiquette and cognitive behavior Conclusion

18. stefan.mangold@philips.com 18 / 27 802.11k medium sensing time histogram With 802.11k, stations can report new measurement results After sensing, results are reported with standardized frames Histogram helps identifying opportunities

19. stefan.mangold@philips.com 19 / 27 Examples … The following slides show the measurement results for the two examples … heavily used  no opportunity unlicensed (4 channels) licensed spectrum, used with deterministic pattern  opportunity

20. stefan.mangold@philips.com 20 / 27 802.11k MSTH measurement results (1/2) Simulation of high channel load (many stations)

21. stefan.mangold@philips.com 21 / 27 802.11k MSTH measurement results (2/2) Periodic (predictable) spectrum usage

22. stefan.mangold@philips.com 22 / 27 Outline 1.Existing standards and limitations IEEE 802.11 wireless LAN Ultra Wideband wireless PAN 2.Agile radio solution New trends in wireless Solution, benefits Architecture 3.Spectrum opportunity identification Spectrum usage patterns IEEE 802.11k radio resource measurement 4.Spectrum opportunity management Horizontal sharing: protection of other agile radios Spectrum etiquette and cognitive behavior 5.Conclusion

23. stefan.mangold@philips.com 23 / 27 Vertical and horizontal sharing Future radio systems should consider the effects of their decisions on other radio systems The opponent may even have a higher regulatory status Information about what is permitted may be disseminated with XG framework (therefore the policy interface)

24. stefan.mangold@philips.com 24 / 27 Spectrum etiquette and mutual cooperation A spectrum etiquette is voluntarily used by a radio system People tend to hesitate to implement voluntary mechanisms –though we learn from game theory that spectrum usage may improve As long as engineers make the rules… –we may have to wait long before we see spectrum etiquette Why don’t we let the radio’s make the decisions? –May require cognitive decision making (awareness) Technocratic decision making:With etiquette: (see ref [1] for further details) throughput per radio system

25. stefan.mangold@philips.com 25 / 27 Outline Existing standards and limitations –IEEE 802.11 wireless LAN –Ultra Wideband wireless PAN Agile radio solution –New trends in wireless –Solution, benefits –Architecture Spectrum opportunity identification –Spectrum usage patterns –IEEE 802.11k radio resource measurement Spectrum opportunity management –Horizontal sharing: protection of other agile radios –Spectrum etiquette and cognitive behavior Conclusion

26. stefan.mangold@philips.com 26 / 27 Conclusion Future radio standards will suffer from regulatory constraints –IEEE 802.11 wireless LAN: constraint on frequency spectrum –Ultra Wideband wireless PAN: limited transmission power –Other regulatory constraints are currently discussed for the TV-band, for emerging standards like IEEE 802.22 We will improve technology –by working on better radio standards In addition, we may want to improve technology –by working on our regulatory framework Agile radio / cognitive radio appears to be a promising step towards more efficient exploitation of the radio spectrum

27. stefan.mangold@philips.com 27 / 27 Further reading … [1]MANGOLD, S. AND SHANKAR N., S. AND BERLEMANN, L. (2005) Spectrum Agile Radio: A Society of Machines with Value-Orientation. Submission to IEEE Infocom 2005. [2]MANGOLD, S. AND ZHONG, Z. AND CHALLAPALI, K. (2004) Spectrum Agile Radio: Radio Resource Measurements for Opportunistic Spectrum Usage. IEEE Globecom 2004 Dallas TX, USA, Nov 2004. [3]CHALLAPALI, K. AND BIRRU, D. AND MANGOLD, S. (2004) Spectrum Agile Radio for Broadband Applications. EETimes In Focus Article Aug 23. [4]CHALLAPALI, K. AND MANGOLD, S. AND ZHONG, Z. (2004) Spectrum Agile Radio: Detecting Spectrum Opportunities. International Symposium on Advanced Radio Technologies 2004 Boulder Colorado USA, Mar 2004. [5]MANGOLD, S. AND ZHONG, Z. AND HIERTZ, G. AND WALKE, B. (2004) IEEE 802.11e/802.11k Wireless LAN - Spectrum Awareness for Distributed Resource Sharing. Special Issue on Emerging WLAN Technologies and Applications. Wireless Communications and Mobile Computing. New York USA: John Wiley & Sons. [6]MANGOLD, S. AND CHALLAPALI, K. (2003) Coexistence of Wireless Networks in Unlicensed Frequency Bands. Wireless World Research Forum #9 Zurich Switzerland July 2003. [7]MANGOLD, S. AND BERLEMANN, L. AND WALKE, B. (2003) Equilibrium Analysis of Coexisting IEEE 802.11e Wireless LANs. IEEE Personal Indoor Mobile Radio Conference Beijing P. R. China 7-11 Sept 2003. [8]BERLEMANN, L. AND MANGOLD, S. AND WALKE, B. (2003) Strategies, Behaviors, and Discounting in Radio Resource Sharing Games. Wireless World Research Forum #10 New York City USA Oct 2003.  http://www.comnets.rwth-aachen.de/~smd http://www.comnets.rwth-aachen.de/~smd

28. stefan.mangold@philips.com 28 / 27 thank you for your attention