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Using Game Theory for Spectrum Sharing Specially in Cognitive Radios

Using Game Theory for Spectrum Sharing Specially in Cognitive Radios. Mohammadreza Ataei Instructor : Prof. J.Omidi. Modeling the Cognition Cycle. Theoretical Background. 1)Non-Cooperative Games a discipline for modeling situations 2) Auction Design

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Using Game Theory for Spectrum Sharing Specially in Cognitive Radios

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  1. Using Game Theory for Spectrum Sharing Specially in Cognitive Radios Mohammadreza Ataei Instructor : Prof. J.Omidi

  2. Modeling the Cognition Cycle

  3. Theoretical Background 1)Non-Cooperative Games • a discipline for modeling situations 2) Auction Design • a method to determine the value of a commodity that has an undetermined or variable price 3) Graph Coloring • assigning a color to the vertices of a bidirectional graph

  4. Non-Cooperative Games • Nash Equilibrium • Pareto-optimality and Price of Anarchy • Pareto Superior • Pareto Optimal: if there exists no other strategy profile that is Pareto-superior to this strategy profile

  5. Graph Coloring Channel allocation problem

  6. Spectrum Sharing Games • unlicensed band wireless systems • Severe interference • Tragedy of commons • cognitive radios • Primary user identification • Potential interference • Cognition & decision making

  7. Games in Unlicensed Bands • Spectrum Sharing among Heterogeneous Wireless Systems • Goal : Maximize The Rate • Strategy : Power Allocation • Spectrum Sharing among WiFi Operators • Goal : maximize the total number of mobile users • Strategy : channel assignment for its own APs

  8. Spectrum Sharing among Heterogeneous Wireless Systems • Non-cooperative • Each System : Power Allocation -> Maximize The Rate : power spectral density • Freq. flat allocation : • -> N.E. (repeated game-> Pareto efficient)

  9. Spectrum Sharing among WiFi Operators • fixed number of channels • Each WiFi operator : channel assignment for its own APs -> maximize the total number of mobile users • Graph Coloring • Local Bargaining : • 2-buyer-1-seller bargains • 1-buyer-multiple-seller bargains • poor performance • -> GLOBAL BARGAINING

  10. Cognitive Radio Games • Opportunistic Spectrum Sharing • Goal : maximize the utilization • Strategy : opportunistic with cooperation channel selection • Auction Based Spectrum Sharing • Goal : maximize payoff minus cost • Strategy : Power Adjusting • Spectrum Sharing in OFDM Networks • Goal : QoS • Strategy : sub-channel selection

  11. Opportunistic Spectrum Sharing • primary users acquire their own radio band • each radio band is divided into several channels • CGs are free to utilize channels as long as they do not interfere with the primary users • CGs cooperate with each other • CGs : channel allocation -> maximum utilization • Secondary users 1 and 3 can emit on channel A • graph coloring • With coordination • Mobile • ->local bargaining

  12. Auction Based Spectrum Sharing • primary user lets secondary users access its spectrum subject to a given power constraint • ->total interference must be below a threshold • auction-based spectrum sharing • CGs : submit bids ->maximize its payoff minus cost • non-cooperative game • -> • total received power :

  13. Spectrum Sharing in OFDM Networks • Each CG : access to the available sub-channels -> Reach QoS constraint in terms of throughput • Solving The Game : NP-hard • Reduce to 2 optimization problems • -> always exists a NE for the non-cooperative • For better results : virtual referee -> limit sub-channel access -> each user must have access to at least one sub-channel

  14. References • Shared Spectrum Company SSC. Dynamic Spectrum Sharing. In Presentation to IEEE Communications Society, 2005. • B. Fette. Cognitive Radio Technology. Newnes, 2006. • J. Mitola III. Cognitive Radio Architecture: The Engineering Foundations of Radio XML. Wiley, 2006. • . Nash. Equilibrium Points in N-person Games. Proceedings of the National Academy of Sciences, 36:48–49, 1950.

  15. Thanks For Your Attention QUESTIONS?

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