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Flexauc : Serving Dynamic Demands in Spectrum Trading Markets with Flexible Auction. Peng Lin, Xiaojun Feng , Qian Zhang, Hong Kong University of Science and Technology INFOCOM 2014. Outline. Background System Models Flexible Auction Design Theoretical and Simulation Results
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Flexauc: Serving Dynamic Demands in Spectrum Trading Markets with Flexible Auction Peng Lin, XiaojunFeng, Qian Zhang, Hong Kong University of Science and Technology INFOCOM 2014
Outline • Background • System Models • Flexible Auction Design • Theoretical and Simulation Results • Future Works and Conclusions
Secondary Spectrum Trading Spectrum Auction
Secondary Spectrum Trading Spectrum Auction Service Provision
Observations • WSPs may have flexible demands and valuations of the channels in the auction.
Observations • Existing works cannot enable flexibility via an computationally efficient scheme • Many works assume at most one winning for any buyer, e.g • TRUST, INFOCOM’09 • TAHES, INFOCOM’12 • GROUPON, INFOCOM’13 • Exponential overhead via VCG auction or Combinatorial auction
One Key Target of this Paper • Enable Flexible auction (Flexauc) while preserving efficiency
Outline • Background • System Models • Flexible Auction Design • Theoretical and Simulation Results • Future Works and Conclusions
System Model and Key Notations • Spectrum holder (SH) • Number of channels: • Bandwidth of each channel: • WSPs, ()
System Model and Key Notations • Spectrum holder (SH) • Number of channels: • Bandwidth of each channel: • WSPs, () • ’s bids in the auction:
System Model and Key Notations • Spectrum holder (SH) • Number of channels: • Bandwidth of each channel: • WSPs, () • ’s bids in the auction: • The SH decides winners and payment for each channel
Truthfulness • One of the most important properties an auction should achieve. • The buyers bid with their true valuations.
Outline • Background • System Models • Flexible Auction Design • Winner Determination • Payment Mechanisms • Theoretical and Simulation Results • Future Works and Conclusions
Winner Determination • Sort the bids in descending order • The highest bids are the winning bids Winning bids
Payment Mechanism • Traditional clearing-price payment mechanism is not truthful can manipulate the clearing-price Clearing-price Winning bids
Payment Mechanism:Uniform Pricing Scheme • Set the unit price as the highest bid from a buyer who wins no channel Winning bids Uniform price
Payment Mechanism:Uniform Pricing Scheme • Limitation • What if we cannot find such a “loser” in the auction? • If , we can always find one such “loser”
Payment Mechanism:Partial Uniform Pricing Scheme • Set the unit price for as the highest bid from another buyer that is lower than ‘s winning bids Price for Winning bids Price for
Outline • Background • System Models • Flexible Auction Design • Theoretical and Simulation Results • Future Works and Conclusions
Truthfulness and Social Welfare • Flexauc is truthful with either the uniform pricing or partial uniform pricing payment mechanism • Flexauc maximizes social welfare
Computational Efficiency • The time complexity of Flexauc is Polynomial with both N and C (). • The partial uniform pricing scheme provides higher revenue for the spectrum holder than the VCG pricing scheme.
Simulation Settings • Total bandwidth: 50MHz • Number of channels: 5-20 • Number of WSPs: • Metrics: • Utility of the WSPs • Revenue of the SH • Social welfare
Truthfulness • : utility when bids truthfully • : utility when bids untruthfully
Comparison of Payment Mechanisms • We treat the VCG payment scheme as a base line and calculated the revenue of the spectrum owner.
Comparison with Non-flexible Auction • Baseline: a buyer submit the same price for all channels and wins one channel
Outline • Background • System Models • Flexible Auction Design • Theoretical and Simulation Results • Future Works and Conclusions
What about the Strategy of the Spectrum Holder? • In this work, is fixed before the auction. • What if the spectrum holder can determine how to partition the spectrum, given a fixed total bandwidth? • Can its revenue further improved?
Conclusions • Flexauc enables the flexible demands and valuations in the secondary spectrum auction. • We proposed two new payment mechanisms which are both truthful and computationally efficient. • The partial uniform pricing mechanism achieves higher revenue for the seller than the VCG scheme
Thanks!Questions? Flexauc: Serving Dynamic Demands in Spectrum Trading Markets with Flexible Auction XiaojunFeng xfeng@cse.ust.hk