1. 1 Equilibrium and Disequilibrium Pricing for Spectrum Trading in Cognitive Radio: A Control-Theoretic Approach Advisor Advisor ： Wei-Yeh Chen Student Student ：楊 于 世 Reference D. Niyato, E. Hossain, “Equilibrium and Disequilibrium Pricing for Spectrum Trading in Cognitive Radio: A Control- Theoretic Approach,” in GLOBECOM Washington DC, pp. 4852 - 4856, Nov. 2007.

2. 2 Outline Introduction System model Spectrum supply and demand functions Pricing for spectrum trading Performance diagram Conclusion

3. 3 Introduction(1/2) Spectrum trading is a concept used to describe the economics of dynamic spectrum sharing in cognitive radio networks. In this paper, we model and analyze spectrum trading in a cognitive radio environment, where the primary service (i.e., spectrum owner) shares the spectrum with the secondary services (i.e., spectrum buyers).

4. 4 Introduction(2/2) In spectrum trading, an equilibrium price is required to satisfy all of the entities in the market. We consider the disequilibrium case where the spectrum price does not conform( 遵守 ) to the market equilibrium.

5. 5 System model Primary and Secondary Services Spectrum Trading Model

6. 6 Primary and Secondary Services We consider a wireless system with a single primary service operating on multiple frequency spectrum. The primary service serves N P, i local connections using the frequency spectrum F i which is of size W i.

7. 7 System model for spectrum sharing.

8. 8 Spectrum Trading Model The price of spectrum in each market depends on the spectrum supply from the primary service and the demand from the secondary service. The primary service/user may not be fully utilized, and the primary service may want to exploit( 利用 ) this spectrum underutilization( 未充分使用 ) and sell the spectrum opportunities to secondary service(s).

9. 9 Spectrum supply and demand functions Primary Service ： Profit and Spectrum Supply Secondary Service ： Utility and Spectrum Demand

10. 10 Pricing for spectrum trading Equilibrium Pricing Disequilibrium Pricing

11. 11 Equilibrium Pricing In this model, the price is used to determine spectrum supply and demand for the primary and the secondary services, respectively. The difference between spectrum demand and supply is then fed back to adjust the price. The price of one frequency band affects the demand for another frequency band.

12. 12 Block diagram of the equilibrium pricing control system. P ： Price S ： Supply D ： Demand λ ： Control parameter

13. 13 Step response of equilibrium prices.

14. 14 Disequilibrium Pricing The price of spectrum F 2 is set to a value which does not conform to the equilibrium. In this case, the excess demand for F 2 is aggregated( 聚集 ) with that of spectrum F 1.

15. 15 Block diagram of the disequilibrium pricing control system.

16. 16 Step response of equilibrium prices under disequilibrium condition.

17. 17 Conclusion 頻譜交易中，平衡與非平衡的概念，在這些機制中，加入 控制參數後，去調整價格，讓市場能達到平衡，使主要頻 譜的擁有者能得到最佳的利益，次要使用者得到最佳的頻 譜服務品質。