COGNITIVE RADIO:A PANACEA FORRF SPECTRUM SCARCITYProfessor Alexander M. WyglinskiWorcester Polytechnic Institute
Presentation Outline2       The Information Age       Wireless Spectrum Characterization       Spectrally Agile Wavefor...
The Information Age
Several Key Innovators4    Marconi           Shannon                 Bardeen               Brattain      Shockley  Wireles...
Progress of Technology5        Cognitive Radio: A Panacea for RF Spectrum Scarcity
6Cognitive Radio: A Panacea for RF Spectrum Scarcity                                                                      ...
Software-Defined Radio Anatomy7                  PROGRAMMABLE                               TUNABLE       Cognitive Radio:...
Sample SDR Platforms8    Universal Software Radio Peripheral 2 (USRP2) Unit.    COSMIAC FPGA board currently being retrofi...
Mitola & Cognitive Radio9          Joseph Mitola III        Cognitive Radio: A Panacea for RF Spectrum Scarcity
Cognitive Radio: A Black Box Model10What you want                                                                 What you...
Flexible RF Front Ends Needed11                           Can I do this                                                   ...
RF MEMS Can Help!12        A single RF front end         would not normally be         able to support a very            ...
RF MEMS13        RF MEMS can be used to implement:          Antennas    (e.g., fractal antennas)          Filters (e.g....
Spectrum Characterization
Electromagnetic Spectrum15        What do you think of when you hear the word         “spectrum”?            Cognitive Ra...
Electromagnetic Spectrum16          Electromagnetic spectrum is the medium upon which wireless           communications i...
How Do You Measure Spectrum?17                                                                                            ...
How Do You Measure Spectrum?18        WPI Wireless Innovation Laboratory NSF-sponsored Measurement Campaign – Summer 2008 ...
How Do You Measure Spectrum?19                                                        SQUIRRELWeb online                 ...
How Do You Measure Spectrum?20     A map of the forty eight locations close to I-90 between Boston, MA     and West Stockb...
How Much Spectrum Is There?21       Spectrum occupancy characteristics in the four mid-size US cities visited during June ...
From A Vehicular Perspective22                                                                                            ...
23Cognitive Radio: A Panacea for RF Spectrum Scarcity                                                                     ...
24                                                                                      locations along I-90.Cognitive Rad...
Spectrally Agile Waveforms
Opportunistic Spectrum Access26        Opportunistic spectrum access (OSA) is a significant         paradigm shift in the...
OSA Motivation27         The utilization efficiency of “prime” wireless spectrum          has been shown to be poor      ...
Leveraging the Electrospace28                                                                      “Cognitive Radio Commun...
Several Possible Approaches29     •   Secondary transmission in licensed spectrum can be         classified into three cat...
Spectral Opportunities!30              empty                                                                      empty   ...
Underlay Solution31                                                                                                       ...
Overlay Solution32                                                                                                      ov...
Multicarrier Transmission Techniques for     Spectrally Opportunistic Communications33        Multicarrier modulation is ...
Multicarrier Overlay Solution34                                                                                           ...
Spectral Agility In Action!35                    PU signal!     As seen in this close-up of      the multicarrier overlay ...
36Cognitive Radio: A Panacea for RF Spectrum Scarcity                                                                     ...
Major Issue: Out-of-band Emission37        Out-of-band (OOB) interference problem with OFDM-based         cognitive radio...
Sinc Pulses Have High OOB Levels!38         Cognitive Radio: A Panacea for RF Spectrum Scarcity
Several Solutions39        Cancellation Carriers          Non-data  bearing subcarriers whose phase and           amplit...
Cancellation Carriers40         Cognitive Radio: A Panacea for RF Spectrum Scarcity
Filtering with CCs41         Cognitive Radio: A Panacea for RF Spectrum Scarcity
Hardware Experimentation42     Photograph of a spectrally agile wireless transceiver     Photograph of a spectrally agile ...
43Cognitive Radio: A Panacea for RF Spectrum Scarcity                                                                     ...
44Cognitive Radio: A Panacea for RF Spectrum Scarcity                                                                     ...
Security Issues
Motivation46        Primary User Emulation (PUE) is a serious threat to         opportunistic spectrum access networks   ...
An Example47                             I’m a                            PU, too!                            Get out     ...
Current Detection Techniques48        Conventional techniques on their own are not         entirely up to the job!!      ...
One Approach49        Combine several techniques in order to detect the         presence of wireless signals as well as t...
“Fingerprinting” Wireless Signals50     Spectral coherence function of QPSK signal in an    Spectral coherence function of...
Simulation Results51                                                                                             Di Pu, Yu...
Experimental Results52       The percentage of correct detection with the hardware implementation                         ...
Additional Enhancements53        Action Recognition Techniques          Often  employed in image and video processing   ...
Concluding Remarks
These Are Interesting Times!55        Numerous advances in cognitive radio, dynamic         spectrum access, and software...
Still Room For Improvement56        There still exists a substantial amount of research         that is needed to make fu...
More Information
Contact Info58                 Professor Alexander Wyglinski        Department of Electrical and Computer Engineering     ...
Cognitive Radio Textbook59        Available since December         2009 (Academic Press)        20 chapters        End-...
Software-Defined Radio Textbook60                                               Anticipated publication: Q1              ...
References61        Alexander M. Wyglinski, Maziar Nekovee, Y. Thomas Hou. Cognitive Radio Communications and Networks: P...
References62        Alexander M. Wyglinski. “Changing the Way Wireless Technology Accesses Electromagnetic Spectrum.” EEW...
References63        Di Pu, Alexander M. Wyglinski. “Primary User Emulation Detection Using Frequency Domain Action Recogn...
References64        Zhou Yuan, Srikanth Pagadarai, and Alexander M. Wyglinski. “Sidelobe Suppression of OFDM Transmission...
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Alex Wyglinski - IEEE VTS UKRI - Cognitive radio - a panacea for RF spectrum scarcity

  1. 1. COGNITIVE RADIO:A PANACEA FORRF SPECTRUM SCARCITYProfessor Alexander M. WyglinskiWorcester Polytechnic Institute
  2. 2. Presentation Outline2  The Information Age  Wireless Spectrum Characterization  Spectrally Agile Waveform Design  Security Issues in Wireless Spectrum  Concluding Remarks Cognitive Radio: A Panacea for RF Spectrum Scarcity
  3. 3. The Information Age
  4. 4. Several Key Innovators4 Marconi Shannon Bardeen Brattain Shockley Wireless Digital TransistorsTransmission Communications Source: Wikipedia Cognitive Radio: A Panacea for RF Spectrum Scarcity
  5. 5. Progress of Technology5 Cognitive Radio: A Panacea for RF Spectrum Scarcity
  6. 6. 6Cognitive Radio: A Panacea for RF Spectrum Scarcity Evolution of Wireless Systems “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009)
  7. 7. Software-Defined Radio Anatomy7 PROGRAMMABLE TUNABLE Cognitive Radio: A Panacea for RF Spectrum Scarcity
  8. 8. Sample SDR Platforms8 Universal Software Radio Peripheral 2 (USRP2) Unit. COSMIAC FPGA board currently being retrofitted for better memory access, to add USB functionality and to make the board SPA compatible. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  9. 9. Mitola & Cognitive Radio9 Joseph Mitola III Cognitive Radio: A Panacea for RF Spectrum Scarcity
  10. 10. Cognitive Radio: A Black Box Model10What you want What you seeWhat you can do What you can tune Cognitive Radio: A Panacea for RF Spectrum Scarcity
  11. 11. Flexible RF Front Ends Needed11 Can I do this 88 MHz with just one 5.8 GHz RF front end? Cognitive Radio: A Panacea for RF Spectrum Scarcity
  12. 12. RF MEMS Can Help!12  A single RF front end would not normally be able to support a very Capacitor wide frequency range Inductor of operations  Radio Frequency Micro- Electro-Mechanical Systems (RF MEMS) can be used to “tune” the RF Close-Up of MEMS Tunable LC Filter. front end to the corresponding frequency Source: Wireless ICs and MEMS Laboratory, McGill University Cognitive Radio: A Panacea for RF Spectrum Scarcity
  13. 13. RF MEMS13  RF MEMS can be used to implement:  Antennas (e.g., fractal antennas)  Filters (e.g., tunable RF bandpass filters)  Oscillators  Real-time operations very difficult to support  Time needed to physically change configurations on the order of seconds  Compared to the rate at which data is transmitted, this is considered to be ages! Cognitive Radio: A Panacea for RF Spectrum Scarcity
  14. 14. Spectrum Characterization
  15. 15. Electromagnetic Spectrum15  What do you think of when you hear the word “spectrum”? Cognitive Radio: A Panacea for RF Spectrum Scarcity
  16. 16. Electromagnetic Spectrum16  Electromagnetic spectrum is the medium upon which wireless communications is realized  Only portions of spectrum are suitable for mobile communications Radio Frequency range 3-30 Hz 30-3000 MHz 30-300 GHz Extremely low Desirable: High bandwidth, Extremely high frequency (ELF) reasonable propagation frequency (EHF) range Not desirable: low Not desirable: short bandwidth, long propagation range, line- propagation range of-sight communication Cognitive Radio: A Panacea for RF Spectrum Scarcity
  17. 17. How Do You Measure Spectrum?17 “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Radio Car – circa 1927 (photo courtesy of the Institute for Telecommunications Science (ITS), NTIA, U.S. Dept. of Commerce) Cognitive Radio: A Panacea for RF Spectrum Scarcity
  18. 18. How Do You Measure Spectrum?18 WPI Wireless Innovation Laboratory NSF-sponsored Measurement Campaign – Summer 2008 Cognitive Radio: A Panacea for RF Spectrum Scarcity
  19. 19. How Do You Measure Spectrum?19  SQUIRRELWeb online spectrum measurement portal  Queue-driven spectrum observatory  Collects specific spectrum measurements upon user request  Available at: http://www.spectrum.wpi.edu Cognitive Radio: A Panacea for RF Spectrum Scarcity
  20. 20. How Do You Measure Spectrum?20 A map of the forty eight locations close to I-90 between Boston, MA and West Stockbridge, MA over which the Toyota-sponsored measurement campaign was conducted in June 2009. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  21. 21. How Much Spectrum Is There?21 Spectrum occupancy characteristics in the four mid-size US cities visited during June 2008 NSF-sponsored measurement campaign. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  22. 22. From A Vehicular Perspective22 UHF TV Channels for Vehicular Dynamic Spectrum Access.” Proceedings of the S. Pagadarai, A. M. Wyglinski, and R. Vuyyuru. “Characterization of Vacant First IEEE Vehicular Networking Conference (Tokyo, Japan), October 2009. Energy Spectral Density plots for the TV frequencies in the frequency range, 600 – 750 MHz over 550 time sweeps close on I-90 between Boston, MA and West Stockbridge, MA. The measurement setup was located in a vehicle moving at an average velocity of 60 miles/hr. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  23. 23. 23Cognitive Radio: A Panacea for RF Spectrum Scarcity Total Available Bandwidth The total available bandwidth for secondary usage at different locations along I-90. S. Pagadarai, A. M. Wyglinski, and R. Vuyyuru. “Characterization of Vacant UHF TV Channels for Vehicular Dynamic Spectrum Access.” Proceedings of the First IEEE Vehicular Networking Conference (Tokyo, Japan), October 2009.
  24. 24. 24 locations along I-90.Cognitive Radio: A Panacea for RF Spectrum Scarcity Spectral Opportunity Analysis Maximum contiguous bandwidth and the number of non-contiguous channel blocks at different S. Pagadarai, A. M. Wyglinski, and R. Vuyyuru. “Characterization of Vacant UHF TV Channels for Vehicular Dynamic Spectrum Access.” Proceedings of the First IEEE Vehicular Networking Conference (Tokyo, Japan), October 2009.
  25. 25. Spectrally Agile Waveforms
  26. 26. Opportunistic Spectrum Access26  Opportunistic spectrum access (OSA) is a significant paradigm shift in the way wireless spectrum is accessed  Instead of PUs possessing exclusive access to licensed spectrum, SUs can temporarily borrow unoccupied frequency bands  SUs must respect the incumbent rights of the PUs with respect to their licensed spectrum  OSA enables greater spectral efficiency and facilitates greater user and bandwidth capacity Cognitive Radio: A Panacea for RF Spectrum Scarcity
  27. 27. OSA Motivation27  The utilization efficiency of “prime” wireless spectrum has been shown to be poor empty empty empty empty A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548) A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  28. 28. Leveraging the Electrospace28 “Cognitive Radio Communications and Networks: Principles and Practice” By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Several dimensions of the electrospace include space, time, and frequency, although there do exist others such as code, polarization, and directional. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  29. 29. Several Possible Approaches29 • Secondary transmission in licensed spectrum can be classified into three categories: – Cooperative Approach • Primary and secondary users coordinate with each other regarding spectrum usage – Underlay Approach • Secondary signals transmitted at very low power spectral density; undetected by primary users • e.g., ultra wideband (UWB) – Overlay Systems • Secondary signals fill in the spectrum unoccupied by primary users Cognitive Radio: A Panacea for RF Spectrum Scarcity
  30. 30. Spectral Opportunities!30 empty empty empty empty A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548) A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  31. 31. Underlay Solution31 underlay transmissions A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548) A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  32. 32. Overlay Solution32 overlay transmissions A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548) A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  33. 33. Multicarrier Transmission Techniques for Spectrally Opportunistic Communications33  Multicarrier modulation is a variant of the conventional frequency division multiplexing (FDM)  Orthogonal Frequency Division Multiplexing (OFDM) an efficient form of multicarrier modulation  In order to utilize unused portions of licensed spectrum, several subcarriers can be turned OFF to avoid interfering with the primary signals  Each subcarrier experiences flat-fading and hence high data-rates are possible if several unused bands of secondary spectrum are available Cognitive Radio: A Panacea for RF Spectrum Scarcity
  34. 34. Multicarrier Overlay Solution34 multicarrier overlay transmissions A snapshot of PSD from 88 MHz to 2686 MHz measured on July 11th 2008 in Worcester, MA (N42o16.36602, W71o48.46548) A. M. Wyglinski, M. Nekovee, Y. T. Hou (Eds.). “Cognitive Radio Communications and Networks: Principles and Practice.” (Chapter 6) Academic Press, December 2009. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  35. 35. Spectral Agility In Action!35 PU signal! As seen in this close-up of the multicarrier overlay transmission, subcarriers located within the vicinity of a PU can be deactivated in order to avoid interference with multicarrier overlay SU that signal. transmission wraps around PU Cognitive Radio: A Panacea for RF Spectrum Scarcity
  36. 36. 36Cognitive Radio: A Panacea for RF Spectrum Scarcity Spectrally Agile Multicarrier H. Bogucka, A. M. Wyglinski, S. Pagadarai, A. Kliks. “Spectrally Agile Multicarrier Waveforms for Opportunistic Wireless Access”. IEEE Communications Magazine, June 2011.
  37. 37. Major Issue: Out-of-band Emission37  Out-of-band (OOB) interference problem with OFDM-based cognitive radios  Power spectral density of the transmit signal over one subcarrier:  Mean relative interference to a neighboring legacy system subband: Cognitive Radio: A Panacea for RF Spectrum Scarcity
  38. 38. Sinc Pulses Have High OOB Levels!38 Cognitive Radio: A Panacea for RF Spectrum Scarcity
  39. 39. Several Solutions39  Cancellation Carriers  Non-data bearing subcarriers whose phase and amplitude values cancel OOB  Modulated Filter Banks  Attenuates OOB in stopband region  Combine cancellation carriers (CCs) with modulated filter banks (MFBs) to attenuate OOB emissions Cognitive Radio: A Panacea for RF Spectrum Scarcity
  40. 40. Cancellation Carriers40 Cognitive Radio: A Panacea for RF Spectrum Scarcity
  41. 41. Filtering with CCs41 Cognitive Radio: A Panacea for RF Spectrum Scarcity
  42. 42. Hardware Experimentation42 Photograph of a spectrally agile wireless transceiver Photograph of a spectrally agile wireless transceiver test-bed at Poznan University of Technology, test-bed at Worcester Polytechnic Institute, Poznan, Poland. Worcester, MA, USA. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  43. 43. 43Cognitive Radio: A Panacea for RF Spectrum Scarcity Spectrally Agile Waveform Results H. Bogucka, A. M. Wyglinski, S. Pagadarai, A. Kliks. “Spectrally Agile Multicarrier Waveforms for Opportunistic Wireless Access”. IEEE Communications Magazine, June 2011.
  44. 44. 44Cognitive Radio: A Panacea for RF Spectrum Scarcity Spectrally Agile Waveform Results P. Kryszkiewicz, H. Bogucka, A. M. Wyglinski. "Protection of Primary Users in Dynamically Varying Radio Environment: Practical Solutions and Challenges." Accepted for publication in the EURASIP Journal on Wireless Communications and Networking, December 23, 2011.
  45. 45. Security Issues
  46. 46. Motivation46  Primary User Emulation (PUE) is a serious threat to opportunistic spectrum access networks  Malicious secondary users can mimic spectral characteristics of primary users to gain priority access to wireless channels  Primary (licensed) users have the priority of using the channel  All the secondary users have equal opportunity to use the channel Cognitive Radio: A Panacea for RF Spectrum Scarcity
  47. 47. An Example47 I’m a PU, too! Get out I’m a of my I’m a I’m a PU! way! PU! PU! frequency Cognitive Radio: A Panacea for RF Spectrum Scarcity
  48. 48. Current Detection Techniques48  Conventional techniques on their own are not entirely up to the job!!  Simple energy detector  Significant probability of missed detection  Matched filter detector  Requires specialized hardware and software  Localization based detector  Can only be employed for stationary primary transmitters with known coordinates Cognitive Radio: A Panacea for RF Spectrum Scarcity
  49. 49. One Approach49  Combine several techniques in order to detect the presence of wireless signals as well as to classify them:  Energy detection  Cyclostationary feature detection  Artificial neural network  Multilayer perceptron (MLP) employed Cognitive Radio: A Panacea for RF Spectrum Scarcity
  50. 50. “Fingerprinting” Wireless Signals50 Spectral coherence function of QPSK signal in an Spectral coherence function of 4FSK signal in an AWGN channel at 10 dB SNR. AWGN channel at 10 dB SNR. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  51. 51. Simulation Results51 Di Pu, Yuan Shi, Andrei Ilyashenko, Alexander M. Wyglinski. "Detecting Primary Global Telecommunications Conference (Houston, TX, USA), November 2011. User Emulation Attacks in Cognitive Radio Networks." Proceedings of the IEEE The detection performance with and without the reliability check. The x-axis represents SNR value, and the y-axis represents the percentage of correct detection. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  52. 52. Experimental Results52 The percentage of correct detection with the hardware implementation Proposed Approach With Check 98.3% Without Check 91.5% Di Pu, Yuan Shi, Andrei Ilyashenko, Alexander M. Wyglinski. "Detecting Primary User Emulation Attacks in Cognitive Radio Networks." Proceedings of the IEEE Global Telecommunications Conference (Houston, TX, USA), November 2011. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  53. 53. Additional Enhancements53  Action Recognition Techniques  Often employed in image and video processing applications, action recognition can also be applied to spectrum measurements  Consists of several parameters:  FeatureVector Construction  Covariance Descriptor of Feature Vectors  Log-covariance Descriptor of Feature Vectors Cognitive Radio: A Panacea for RF Spectrum Scarcity
  54. 54. Concluding Remarks
  55. 55. These Are Interesting Times!55  Numerous advances in cognitive radio, dynamic spectrum access, and software-defined radio have recently occurred  Secondary access of digital TV spectrum  Ratification of IEEE 802.22, IEEE 802.11af standards  Today’s wireless landscape is quickly changing due to new capabilities of wireless transceiver devices  Largely due to smaller, faster processing devices resulting from applications such as smart phones Cognitive Radio: A Panacea for RF Spectrum Scarcity
  56. 56. Still Room For Improvement56  There still exists a substantial amount of research that is needed to make future wireless devices such as cognitive radio more reliable  Ensuring minimal interference to other wireless transmissions  Enabling real-time decision-making and transmission operations  Making RF spectrum access more reliable for everyone involved Cognitive Radio: A Panacea for RF Spectrum Scarcity
  57. 57. More Information
  58. 58. Contact Info58 Professor Alexander Wyglinski Department of Electrical and Computer Engineering Worcester Polytechnic Institute Atwater Kent Laboratories, Room AK230 508-831-5061 alexw@ece.wpi.edu http://www.wireless.wpi.edu/ Cognitive Radio: A Panacea for RF Spectrum Scarcity
  59. 59. Cognitive Radio Textbook59  Available since December 2009 (Academic Press)  20 chapters  End-of-chapter problems (with solutions guide)  Presentation slides for most chapters  Covers physical and network layers, in addition to current platforms and standards http://www.wireless.wpi.edu/?page_id=29 Cognitive Radio: A Panacea for RF Spectrum Scarcity
  60. 60. Software-Defined Radio Textbook60  Anticipated publication: Q1 2013 (Artech House Publishers)  10 comprehensive chapters  Fundamentals in signals & systems, probability, and digital communications  “Hands on” approach to learning digital communication concepts using SDR and Simulink  End-of-chapter problems  Corresponding course lecture slides Cognitive Radio: A Panacea for RF Spectrum Scarcity
  61. 61. References61  Alexander M. Wyglinski, Maziar Nekovee, Y. Thomas Hou. Cognitive Radio Communications and Networks: Principles and Practice, Academic Press, December 2009.  Pawel Kryszkiewicz, Hanna Bogucka, Alexander M. Wyglinski. "Protection of Primary Users in Dynamically Varying Radio Environment: Practical Solutions and Challenges." Accepted for publication in the EURASIP Journal on Wireless Communications and Networking, December 23, 2011.  Si Chen, Srikanth Pagadarai, Rama Vuyyuru, Alexander M. Wyglinski, Onur Altintas. “Feasibility Analysis of Vehicular Dynamic Spectrum Access via Queueing Theory Model.” IEEE Communications Magazine, November 2011.  Srikanth Pagadarai, Adrian Kliks, Hanna Bogucka, Alexander M. Wyglinski. “Non-contiguous Multicarrier Waveforms in Practical Opportunistic Wireless Systems.” IET Radar, Sonar, and Navigation Journal, vol. 5, no. 6, pp. 674-680, July 2011.  Hanna Bogucka, Alexander M. Wyglinski, Srikanth Pagadarai, Adrian Kliks. “Spectrally Agile Multicarrier Waveforms for Opportunistic Wireless Access”. IEEE Communications Magazine, June 2011.  Srikanth Pagadarai, Alexander M. Wyglinski. “A Linear Mixed Effects Model of Wireless Spectrum Occupancy.” EURASIP Journal on Wireless Communications and Networking, August 2010.  Zhou Yuan, Alexander M. Wyglinski. “On Sidelobe Suppression for Multicarrier-Based Cognitive Radio Transceivers.” IEEE Transactions on Vehicular Technology, May 2010.  Chittabrata Ghosh, Srikanth Pagadarai, Dharma P. Agrawal, Alexander M. Wyglinski. “A Framework for Statistical Wireless Spectrum Occupancy Modeling.” IEEE Transactions on Wireless Communications, Vol. 9, No. 1, Pages 38-44, January 2010.  Timothy Newman, Daniel DePardo, Alexander Wyglinski, Joseph B. Evans, Rakesh Rajbanshi, Victor R. Petty, Dinesh Datla, Frederick Weidling, Paul Kolodzy, Michael Marcus, Gary J. Minden, James Roberts. “Measurements and Analysis of Secondary User Device Effects on Digital Television Receivers.” EURASIP Journal on Advances in Signal Processing – Special Issue on “Dynamic Spectrum Access for Wireless Networking”, August 2009. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  62. 62. References62  Alexander M. Wyglinski. “Changing the Way Wireless Technology Accesses Electromagnetic Spectrum.” EEWeb Pulse Magazine, Issue 14, 4 October 2011. [ONLINE]: http://www.eeweb.com/pulse/issue-14-2011  Si Chen, Rama Vuyyuru, Onur Altintas, Alexander M. Wyglinski. “Learning in Vehicular Dynamic Spectrum Access Networks: Opportunities and Challenges.” Proceedings of the International Symposium on Intelligent Signal Processing and Communication Systems, (Chiang Mai, Thailand), December 2011.  Di Pu, Yuan Shi, Andrei Ilyashenko, Alexander M. Wyglinski. "Detecting Primary User Emulation Attacks in Cognitive Radio Networks." Proceedings of the IEEE Global Telecommunications Conference (Houston, TX, USA), November 2011.  Si Chen, Rama Vuyyuru, Onur Altintas, Alexander M. Wyglinski. “On Optimizing Vehicular Dynamic Spectrum Access Networks: Automation and Learning in Mobile Wireless Environments.” Proceedings of the IEEE Vehicular Network Conference (Amsterdam, The Netherlands), November 2011.  Tayyar Rzayev, Yuan Shi, Anastasios Vafeiadis, Srikanth Pagadarai, Alexander M. Wyglinski. “Implementation of a Vehicular Networking Architecture Supporting Dynamic Spectrum Access.” Proceedings of the IEEE Vehicular Network Conference (Amsterdam, The Netherlands), November 2011.  Onur Altintas, Mitsuhiro Nishibori, Takuro Oshida, Yutaka Ihara, Masahiro Saito, Chikara Yoshimura, Youhei Fujii, Kota Nishida, Kazuya Tsukamoto, Masato Tsuru, Yuji Oie, Rama Vuyyuru, Abdulrahman Al Abbasi, Masaaki Ohtake, Mai Ohta, Takeo Fujii, Si Chen, Srikanth Pagadarai, Alexander M. Wyglinski. "Demonstration of Vehicle to Vehicle Communications over TV White Space." Proceedings of the 4th International Symposium on Wireless Vehicular Communications (San Franscisco, CA, USA), September 2011.  Sean Rocke, Alexander M. Wyglinski. “Geo-Statistical Analysis of Wireless Spectrum Occupancy using Extreme Value Theory.” Proceedings of the 2011 IEEE Pacific Rim Conference on Communications, Computers, and Signal Processing (Victoria, BC, Canada), August 2011. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  63. 63. References63  Di Pu, Alexander M. Wyglinski. “Primary User Emulation Detection Using Frequency Domain Action Recognition.” Proceedings of the 2011 IEEE Pacific Rim Conference on Communications, Computers, and Signal Processing (Victoria, BC, Canada), August 2011.  Si Chen, Alexander M. Wyglinski, Rama Vuyyuru, Onur Altintas. “Feasibility Analysis of Vehicular Dynamic Spectrum Access Via Queueing Theory Model”. Proceedings of the IEEE Vehicular Networking Conference (Jersey City, NJ, USA), Dec. 2010.  Srikanth Pagadarai, Adrian Kliks, Hanna Bogucka, Alexander M. Wyglinski. “On Non-contiguous Multicarrier Waveforms for Spectrally Opportunistic Cognitive Radio Systems”. Proceedings of the 5th International Waveform Diversity and Design Conference (Niagara Falls, ON, Canada), August 2010.  Srikanth Pagadarai, Alexander M. Wyglinski, and Rama Vuyyuru. “Characterization of Vacant UHF TV Channels for Vehicular Dynamic Spectrum Access.” Proceedings of the First IEEE Vehicular Networking Conference (Tokyo, Japan), October 2009.  Zhou Yuan, Srikanth Pagadarai, Alexander M. Wyglinski. “Feasibility of NC-OFDM Transmission in Dynamic Spectrum Access Networks.” Proceedings of the 2009 Military Communications Conference (Boston, MA, USA), October 18, 2009.  Zhou Yuan and Alexander M. Wyglinski. “Cognitive Radio-Based OFDM Sidelobe Suppression Employing Modulated Filter Banks and Cancellation Carriers.” Proceedings of the 2009 Military Communications Conference (Boston, MA, USA), October 18, 2009.  Chittabrata Ghosh, Srikanth Pagadarai, Dharma P. Agarwal, and Alexander M. Wyglinski. “Queuing Theory Representation and Modeling of Spectrum Occupancy Employing Radio Frequency Measurements.” Proceedings of the IEEE Vehicular Technology Conference (Anchorage, AK, USA), September 20, 2009.  Srikanth Pagadarai and Alexander M. Wyglinski. “A Quantitative Assessment of Wireless Spectrum Measurements for Dynamic Spectrum Access.” Proceedings of the International Conference on Cognitive Radio Oriented Wireless Networks and Communications (Hannover, Germany), June 22, 2009. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  64. 64. References64  Zhou Yuan, Srikanth Pagadarai, and Alexander M. Wyglinski. “Sidelobe Suppression of OFDM Transmissions using Genetic Algorithm Optimization.” Proceedings of the IEEE Military Communications Conference (San Diego, CA, USA), November 2008.  Srikanth Pagadarai and Alexander M. Wyglinski. “A Sub-optimal Sidelobe Suppression Technique for OFDM-based Cognitive Radios.” Proceedings of the IEEE Military Communications Conference (San Diego, CA, USA), November 2008.  Srikanth Pagadarai and Alexander M. Wyglinski. “Novel Sidelobe Suppression Technique for OFDM-Based Cognitive Radio Transmission.” Proceedings of the IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (Chicago, IL, USA), October 2008.  Srikanth Pagadarai, Rakesh Rajbanshi, Alexander M. Wyglinski, and Gary J. Minden. “Sidelobe Suppression for OFDM-Based Cognitive Radios Using Constellation Expansion.” Proceedings of the IEEE Wireless Communications and Networking Conference (Las Vegas, NV, USA), April 2008.  Dinesh Datla, Alexander M. Wyglinski, and Gary J. Minden. “A Statistical Approach to Spectrum Measurement Processing.” Proceedings of the 2007 Virginia Tech Symposium on Wireless Personal Communications (Blacksburg, VA, USA), June 2007.  Rakesh Rajbanshi, Victor R. Petty, Dinesh Datla, Frederick Weidling, Daniel DePardo, Paul J. Kolodzy, Michael. J. Marcus, Alexander M. Wyglinski, Joseph B. Evans, Gary J. Minden, and James A. Roberts. “Feasibility Study of Dynamic Spectrum Access in Underutilized Television Bands.” Proceedings of the Second IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (Dublin, Ireland), April 2007.  Rakesh Rajbanshi, Qi Chen, Alexander M. Wyglinski, Gary J. Minden, and Joseph B. Evans. “Quantitative Comparison of Agile Modulation Techniques for Cognitive Radio Transceivers.” Proceedings of the IEEE Consumer Communications and Networking Conference – Workshop on Cognitive Radio Networks (Las Vegas, NV, USA), January 2007.  Rakesh Rajbanshi, Qi Chen, Alexander M. Wyglinski, Joseph B. Evans, and Gary J. Minden. “Comparative Study of Frequency Agile Data Transmission Schemes for Cognitive Radio Transceivers.” Proceedings of the First International Workshop on Technology and Policy for Accessing Spectrum (Boston, MA, USA), July 2006. Cognitive Radio: A Panacea for RF Spectrum Scarcity
  65. 65. Thank You!

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