Equilibrium and Disequilibrium Pricing for
Spectrum Trading in Cognitive Radio: A
Control-Theoretic Approach
Advisor ：Wei-Yeh Chen
Student ：楊


于
世
Reference
D. Niyato , E. Hossain, “Equilibrium and Disequilibrium
Pricing for Spectrum Trading in Cognitive Radio: A ControlTheoretic Approach,” in GLOBECOM Washington DC, pp.
4852 - 4856 , Nov. 2007 .
1
Outline

Introduction

System model

Spectrum supply and demand functions

Pricing for spectrum trading

Performance diagram

Conclusion
2
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).
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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.
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System model

Primary and Secondary Services

Spectrum Trading Model
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Primary and Secondary Services

We consider a wireless system with a single primary
service operating on multiple frequency spectrum.

The primary service serves NP,i local connections using the
frequency spectrum Fi which is of size Wi.
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System model for spectrum sharing.
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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).
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Spectrum supply and demand functions

Primary Service： Profit and Spectrum Supply

Secondary Service：Utility and Spectrum Demand
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Pricing for spectrum trading

Equilibrium Pricing

Disequilibrium Pricing
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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.
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P：Price
S：Supply
D：Demand
λ：Control parameter
Block diagram of the equilibrium pricing control system.
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Step response of equilibrium prices.
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Disequilibrium Pricing

The price of spectrum F2 is set to a value which does not
conform to the equilibrium.

In this case, the excess demand for F2 is aggregated(聚集)
with that of spectrum F1.
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Block diagram of the disequilibrium pricing control system.
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Step response of equilibrium prices under disequilibrium condition.
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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。
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