1. Mohammadreza Ataei Instructor : Prof. J.Omidi

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3. 3 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. 4  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. 5 Channel allocation problem

6. 6  unlicensed band wireless systems ◦ Severe interference ◦ Tragedy of commons  cognitive radios ◦ Primary user identification ◦ Potential interference ◦ Cognition & decision making

7. 7  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. 8  Non-cooperative  Each System : Power Allocation -> Maximize The Rate : power spectral density  Freq. flat allocation :  -> N.E. (repeated game-> Pareto efficient)

9. 9  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

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11. 11  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

12. 12  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

13. 13  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 :

14. 14  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

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16. 16  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.

17. 17 Thanks For Your Attention QUESTIONS?