1. Dynamic Spectrum Access Technology, Cognitive Radio, and Spectrum Sensing
Younes Abdi, PhD
Faculty of Information Technology
University of Jyväskylä

2. Outline Introduction What is Dynamic Spectrum Access (DSA)?
Cognitive Radio (CR)
Cognitive Radio Network Architecture
IEEE Standards Supporting CR and DSA
Applications
Spectrum Sensing
Cooperative Spectrum Sensing
Tradeoffs in Cooperative Sensing
Summary
References

3. Introduction
The Radio Spectrum

4. Introduction
Different spectrum bands for different services

5. Introduction
The radio spectrum is crowded

6. Introduction
The spectrum is underutilized
Spectrum utilization [1]

7. Dynamic Spectrum Access (DSA)
The White Space concept
Primary Users (PU) and Secondary Users (SU)
The concepts of white space and dynamic spectrum access [1]

8. Dynamic Spectrum Access (DSA)
Implemented by Cognitive Radios (CR)
Self-awareness, context-awareness, and adaptability
Definition of CR [2]:
A cognitive radio is a radio whose control processes permit the radio to leverage situational knowledge and intelligent processing to autonomously adapt towards some goal.
Intelligence is the capacity to acquire and apply knowledge, especially, toward a purposeful goal.

9. Cognitive Radio (CR) Architecture
Components of a cognitive radio system [3]

10. Cognitive Radio Network Architecture: Primary and Secondary Users
CR Network Architecture [1]

11. IEEE Standards Supporting CR and DSA functionalities
The evolution of IEEE standardization activities relating to CR and DSA © 2008 IEEE.

12. The IEEE 802.22 Standard Wireless RAN TV-Band Devices
Geolocation/Database
Spectrum Sensing
wireless RAN classification as compared
to other popular wireless standards © 2006 IEEE.

13. Applications of Cognitive Radio

14. Applications of Cognitive Radio
Wireless Cellular Networks
Public Safety Networks
Smart Grid
Wireless Medical Networks …

15. CR Applications: Smart Grid
An IEEE based smart grid architecture © 2011 IEEE.

16. Spectrum Sensing in Cognitive Radios
CRs listen to their radio environment
Various signal processing techniques
Sensing quality is vulnerable to wireless impairments
The sensing quality is enhanced with cooperative communication techniques

17. Cooperative Spectrum Sensing
The hidden node problem and need for cooperative spectrum sensing
The hidden node problem in a CRN [3]

18. Cooperative Sensing
Three step: Local sensing, reporting, decision/data fusion
Basic configuration of centralized cooperative spectrum sensing

19. Proposed Sensing Structures
The sensing-throughput tradeoff
Joint reporting-fusion optimization
Random Interruptions in Cooperation

20. The Sensing-Throughput Tradeoff
Energy consumed by a sensing CR vs. the maximum throughput achieved.

21. Joint Reporting-Fusion Optimization
Linear fusion of quantized reports in cooperative sensing.

22. Performance of the Joint Optimization
Performance of the proposed joint reporting-fusion optimization scheme compared with the optimal linear combining.

23. Random Interruptions in Cooperation
Linear fusion of quantized reports in cooperative sensing.

24. Performance of the Random Interruptions
Performance of the proposed method and linear
cooperative sensing

25. Summary Radio spectrum DSA technology Cognitive radio
Spectrum sensing in cognitive radios
Cooperative spectrum sensing

26. Selected References
[1] I. F. Akyildiz, W.-Y. Lee, M. C. Vuran, and S. Mohanty, “A survey on spectrum management in cognitive radio networks,” IEEE Communications Magazine, vol. 46, no. 4, pp. 40–48, 2008.
[2] J. O. Neel, “Analysis and design of cognitive radio networks and distributed radio resource management algorithms,” Ph.D. dissertation, Virginia Polytechnic Institute and State University, 2006.
[3] M. Sherman, A. N. Mody, R. Martinez, C. Rodriguez, and R. Reddy, “IEEE standards supporting cognitive radio and networks, dynamic spectrum access, and coexistence,” IEEE Communications Magazine, vol. 46, no. 7, pp. 72–79, 2008.
[4] I. F. Akyildiz, B. F. Lo, and R. Balakrishnan, “Cooperative spectrum sensing in cognitive radio networks: A survey,” Elsevier Physical Communications, vol. 4, no. 1, pp. 40–62, March
[5] J. Mitola, Cognitive Radio—An Integrated Agent Architecture for Software Defined Radio. Royal Institute of Technology (KTH), 2000.
[6] Y. Abdi and T. Ristaniemi, “Joint Local Quantization and Linear Cooperation in Spectrum Sensing for Cognitive Radio Networks,” IEEE Transactions on Signal Processing, vol. 62,
no. 17, pp , Sept. 1, 2014.
[7] Y. Abdi and T. Ristaniemi, “Random Interruptions in Cooperation for Spectrum
Sensing in Cognitive Radio Networks,” IEEE Transactions on
Communications (accepted for publication), 2016.

27. Thank you for your kind attention!