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By: Gamal El Din Fathy Amin Ahmed Ossama El Fiky Supervised By: Dr Tarek El Naffouri

Cognitive Radio Protocol: Implementation of Compressive Sensing Techniques for Optimization of Control Channels. By: Gamal El Din Fathy Amin Ahmed Ossama El Fiky Supervised By: Dr Tarek El Naffouri. Outline . Introduction. Why Cognitive Radio? Issues. Benefits. Applications.

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By: Gamal El Din Fathy Amin Ahmed Ossama El Fiky Supervised By: Dr Tarek El Naffouri

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  1. Cognitive Radio Protocol: Implementation ofCompressive Sensing Techniques for Optimizationof Control Channels By: Gamal El Din Fathy Amin Ahmed Ossama El Fiky Supervised By: Dr Tarek El Naffouri

  2. Outline • Introduction. • Why Cognitive Radio? • Issues. • Benefits. • Applications. • Challenges. • Our Approach. • Proposed Protocol.

  3. Introduction • CR  Intelligent Wireless Technology. • a radio that is aware of its surroundings and adapts intelligentlyIntelligence Searching the spectrum. • Cognitive radio requirements • co-exists with legacy wireless systems • uses their spectrum resources • does not interfere with them

  4. Introduction • Embedded intelligence to determine optimal transmission and vary communication parameters (bandwidth, center frequency, QoS) based on primary users’ behavior • Defining new concepts: • Spectrum sharing. • Adaptive parameters.

  5. Why CR? • Recent measurements by the FCC in the US show 70% of the allocated spectrum is not utilized. (Spectrum scarcity)

  6. Why CR? • Bandwidth is expensive and good frequencies are taken • Unlicensed bands – biggest innovations in spectrum efficiency. • Spectrum utilization.

  7. Applications • Band sharing, emergency services, broadband wireless services, multi-media networking • Non-time sensitive services, such as downloading could be most appropriate.

  8. Cont. Application • Cellular operator • Local KAUST free mobile network. • Sensing is limited of the operator’s band.

  9. Challenges • Hidden tunnel  Cooperative Spectrum Sensing • Controlling CRs to ensure they have the same spectrum picture. • Spectrum sharing • Could add lots of interference. • Scarcer resources. • A lot of control communications (increase throughput)

  10. Our Approach.

  11. What is Compressive Sensing? • Mathematical tool that can help in reducing the number of measurements to solve a system given it is sparse.

  12. Cont. What is Compressive Sensing? • N equations is needed to solve this system. • M=N.

  13. Cont. What is Compressive Sensing? • S = number of nonzero elements in U. • S<<N • m = α S log (n/S) & S<<m<<N

  14. Control Channels On Cognitive radio. • Handles the control communication between Cognitive base station (CBS) and Cognitive Radios (CR). • Ex. spectrum sensing information. • Share scarce resources. • Collision Happens. • Collision Resolving Algorithms Should Be Applied. • The channel is given to the strongest connection users: • Support Higher rates. • Increase throughput.

  15. Control Channels On Cognitive radio. Reservation Data • Increase Throughput: • Increase the frame length. • Decrease Reservation Time

  16. Control Channels On Cognitive radio. Reservation Data

  17. Apply Compressive Sensing to Optimize the number of slots. Reservation Data

  18. Compressive Sensing Protocol • CBS has fixed reservation slots=m. • CBS sends a beacon with a threshold level L. • CRs compare their channel gain a with L. • If a>L Strong Connection CR (SCR) • Otherwise, Weak connection (WCR)

  19. Cont. Compressive Sensing Protocol • WCR go to sleep mode. • Saves Battery. • Eliminate WCRs that can cause slow rates and interference. • SCR multiplies 1 by random sequence of length m +1 &-1 and reply on all slots.

  20. Cont. Compressive Sensing Protocol • CBS receives the replies and form the system of independent equations. • CBS then knows SCRs. • It reserves the channel randomly to any of SCRs.

  21. Cont. Compressive Sensing Protocol • CBS senses the spectrum and send the spectrum information to SCRs. • SCRs sense spectrum and compare with CBS. • If SCRs agree it remains silent and apply the decision. • If SCRs object they reply back. • CBS base a new decision on the amount of objection to its decision.

  22. Cont. Compressive Sensing Protocol • Advantages: • Shared control channels are used. • Limit collision by limiting the number of users. • decrease reservation time and increase data time. • Strong connection users only use channel.

  23. Questions

  24. Control Channels On Cognitive radio • Traditional way N users send their ID and Channel gain G to reserve the channel.

  25. Apply Compressive Sensing to decrease reservation Time • If N is limited to s users need to send s<<N, compressive sensing can be used. • m reservation slots is used each of one bit.

  26. The goal • Increase throughput. • Give channels to strong connection users. • They support high rates. • Limit the activity of weak connection users.

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