Mohammadreza Ataei
Instructor : Prof. J.Omidi
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1)Non-Cooperative Games
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a discipline for modeling situations
2) Auction Design
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a method to determine the value of a commodity that has an
undetermined or variable price
3) Graph Coloring
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assigning a color to the vertices of a bidirectional graph
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Nash Equilibrium
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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
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Channel allocation problem
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unlicensed band wireless systems
◦ Severe interference
◦ Tragedy of commons
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cognitive radios
◦ Primary user identification
◦ Potential interference
◦ Cognition & decision making
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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
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Non-cooperative
Each System : Power Allocation -> Maximize The Rate
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: power spectral density
Freq. flat allocation :
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-> N.E. (repeated game-> Pareto efficient)
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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
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poor performance
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-> GLOBAL BARGAINING
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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
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Spectrum Sharing in OFDM Networks
 Goal : QoS
 Strategy : sub-channel selection
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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
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graph coloring
◦ With coordination
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Mobile
◦ ->local bargaining
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primary user lets secondary users access its spectrum
subject to a given power constraint
◦ ->total interference must be below a threshold
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auction-based spectrum sharing
CGs : submit bids ->maximize its payoff minus cost
non-cooperative game
->
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total received power :
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Each CG : access to the available sub-channels
-> Reach QoS constraint in terms of throughput
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Solving The Game : NP-hard
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Reduce to 2 optimization problems
◦ -> always exists a NE for the non-cooperative
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For better results : virtual referee
-> limit sub-channel access
-> each user must have access to at least one sub-channel
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

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.
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Thanks For Your Attention
QUESTIONS?
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