Fostering Wireless Spectrum Sharing via Subsidization
Allerton 2013
Murat Yuksel Computer Science and Engineering Department,
University of Nevada, Reno
Joint with T. Quint, I. Guvenc, W. Saad, and N. Kapucu
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Outline
Pervasive Spectrum Sharing Overview Challenges and need for subsidy
Proposed Spectrum Subsidization Market Market Model Formulation as a non-cooperative game Roles of customers, providers, government
Key insights and observations Conclusion and future work
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Demand for Radio Spectrum
Demand for wireless capacity to double every year (Cisco) Re-thinking the way in which spectrum is shared
Allocating additional spectrum/re-assigning spectrum Opening up spectrum for unlicensed use (cognitive) New architectures (HetNets) and technologies (D2D)
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Challenges to Spectrum Sharing
Operators paid a lot of money to acquire their spectrum Need incentive for opening up their spectrum
Existing spectrum sharing approaches (auctions) are rather “closed” but must remain intact How to allow sharing along with such auctions?
Success of new technologies such as D2D is contingent upon a “pervasive” spectrum sharing Need for subsidization!
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Subsidization
What is subsidization? Government policies to encourage operators to open
their spectrum to “roaming” users Governmental regulatory incentives for providers
Many existing works on regulations in different disciplines Often ignore the idea of “performance-based” subsidy Do not focus on the role of subsidy in seamless
spectrum sharing Role of government less explicit
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Market Model Customers
choose provider based on QoS & fee
Providers allocate bandwidth
and subsidy money in regions
Government subsidize, encourage
serving roaming users
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Market Model
Seamless to customers Customers subscribe to a home provider Then pick the best quality signal offered by the providers
participating in the subsidy market Customers with no home providers are possible!
Performance-based Providers have to return a portion of the subsidy money if
insufficient “foreign” (roaming) customers are served Steerable policy
Government can steer the market via a more aggressive penalty function – potentially per region
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Game Formulation
Two-stage, extensive form non-cooperative game Players: Providers, Government Extensive form since: government moves first, followed
by providers (move simultaneously) Customers not involved in the game as their actions are
a byproduct of providers/government interactions Solution: Perfect Nash equilibrium
Knowing customers actions, solve for providers Knowing customers/providers actions, solve for
government subsidy
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Game Formulation
Choice of customer i Choose provider with probability (contest theory):
Provider’s problem Total revenue in a region:
No. Calls in “home region”
Fee charged by provider j
Intensity of signal of provider j in
region k Selection based on signal quality &
subscription fee
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Game Formulation
Provider’s problem
Constraints
# foreign calls:
Penalty function on the number of “foreign calls”
Investment and BW designated for region k
Total subsidy
Total investment
Selection purely based on signal
quality
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Game Formulation
Government’s problem Maximize customers total utility
Analytical solution for equilibrium complex but.. …several insights can be derived …key observations
Utility from local calls
Utility from foreign calls
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Key Observations
Providers are unlikely to get hurt by subsidy Providers are free not to take subsidization option if it hurts
their revenues (seen from optimization problem) Conservative government penalization can lead to easy
providers participation The government can provide large subsidy with low risks and
incentivize providers Providers will be motivated to invest in a non-overlapping
manner and collectively cover a larger area
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Key Observations
: As the # of customer calls to “foreign providers” increases, subsidization becomes more beneficial particularly to small providers Providers with only few home regions can take subsidization and
promote “pervasive” sharing : small providers are able to compete with large
providers Monopolies avoided as long as providers are attracted to
subsidization
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Conclusions and Future Works
Subsidization could play a key role in enabling pervasive spectrum sharing
The success of technologies such as D2D depends not only on the “technical” aspects but also on policy and economic aspects
Future works Extending the model and providing quantitative closed form
solutions to subsidization at equilibrium Heterogeneous providers Specific technologies
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Finally….
Thank You, Questions ?
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