A Combinatorial Cloic k Auction for OFDMA-based · 2008. 6. 10. · Linda Do iy le & Tim Fo ir de...

Linda Doiyle & Tim Foirde

Centre for Telecommunications Value-chain Research (CTVR)Trinity College, University of Dublin, Ireland.

A Coimbinatorial Cloick Auction for OFDMA-based Cognitive Wireless Networks

From Software-defined to Cognitive.

• Our motivating application is Dynamic Spectrum Access / Dynamic Spectrum Access Networks– exploitation of technology & policy & economic change

• IRIS – the CTVR SDR-based node– highly reconfigurable component-based architecture– Windows, Linux, FPGAs – multiple RF frontends

• IRIS is but one SDR-based system. There are more. There will be many.

ISWPC - Santorini, Greece - 7-9, May 2008

• Difference exists– radio:

• multiple SDRs• multiple waveform capabilities• multiple architectures – abilities/constraints• frequency agility constraintsdefines where/how radios can access spectrum

– network:• centralised/distributed• planned/infrastructure – MANET/ad hoc• open/closed• service/application demands influences/defines where/how radios should access spectrum


Heterogeny.

Exclusive Assignments, Flexible Use

License Free, Unrestricted Access,

Flexible Use

LICENSED COMMONS

Heterogeny.– policy

exclusive spectrum assignments

overlay: opportunistic use

underlay: easement use

Heterogeny.


Heterogeny.

• In the absence of heavy regulation, how are competing (excess) demands for exclusive access reconciled?

• Too much choice, too many variables for an oracle (i.e. FCC, OFCOM, Comreg)

• multi-objective, multiply constrained systems• space/time/frequency varying

• Push decisions onto the radio/network– let the node/network decide, plan, strategise– let the node/network take the risk

• Let the spectrum be accessed by those who value it the most.– What is the price of spectrum at any time, place and for a

specific band?


Heterogeny.

1 Hz = ?$€¥

• Coordination• Coexistence• Collaboration


Cognition.

multi-lateralnetwork level

cognitiveprocessing

multi-lateralnetwork level

cognitiveprocessing

unilateralnode levelcognitive

processing

unilateralnode levelcognitive

processing

plan

decide

learn

observe

orient

cogn

itive

cyc

le

• Coordination• Coexistence• Collaboration• Competition

– when there is excess demand for a resource, CRs/CNs can compete for it in a market

– the mechanism should be flexible, i.e. should accommodate competition for the resource between different radios, different networks, different demands


Cognition.


Coimbinatorial Auctions.

• Why?– No regulator. No oracle. No predefined licences.– Aim to break the resource into the smallest feasibly

accessible units.

– Let the intended users assemble packages, i.e. combine bundles of base units (whatever they are) as they see fit.

Coimbinatorial Auctions.

• Benefits– reduces financial exposure of bidders– bidders can package distinct complementary auction

items into a single bid using logical terms which reflect internalised technical/economic constraints

– allows for expressive bidding

• Challenges– computational complexity makes them rare in practice– there may be inconceivably many packages on which the

bidder wants to bid– perverse/strategic bidding


Coimbinatorial Cloick Auction

• The coimbinatorial cloick auction combines an iterative discovery/search process with revelation-inducing pricing.

• Properties– efficiency in achieving all gains from trade– task simplicity for bidders– anonymous, monotonic linear pricing– computational feasibility– the auction mechanism is transparent

• others’ bidding activities are not known• strategic behaviour mitigated

– price discovery


(Cooperative) Competition.


3 4 5 .. ..21 N..

OFDM data subcarriers

2 .. .. OFDM symbols

1 M 134

2

5

Downlink bandwidth Uplink bandwidth


Package Bid

Package Bid 61 62 63 647 8 … 11 12

2 3 … 10 55 … 61 62

Bidder X:

Bidder Y:

3 4 5 .. ..21 N..

OFDM data subcarriers

2 .. .. OFDM symbols

1 M 134

2

5

Downlink bandwidth Uplink bandwidth


Set reserve clock prices for each unit. 1

3 4 5 .. ..21 N 2 ..1 MM -1N -1

1

2

3

4

5

6

€/

$ /

¥Reserve Price (round 0):


Set reserve clock prices for each unit.

Post prices to all bidders.

1

2 3 4 5 .. ..21 N 2 ..1 MM -1N -1

1

2

3

4

5

6

€/

$ /





Bidders react to prices. Notify auctioneer.

1

2

3

3 4 5 .. ..21 N 2 ..1 MM -1N -1

1

2

3

4

5

6

€/

$ /






1

2

3

Auctioneer checks for excess demand?

4

3 4 5 .. ..21 N 2 ..1 MM -1N -1

1

2

3

4

5

6

€/

$ /






1

2

3


Auctioneer raises clock prices of items in excess demand.

4

5

YES

3 4 5 .. ..21 N 2 ..1 MM -1N -1

1

2

3

4

5

6

€/

$ /

¥round 1 :





1

2

3



4

5

CLOCK PHASE

YES

3 4 5 .. ..21 N 2 ..1 MM -1N -1

1

2

3

4

5

6

€/

$ /

¥round 3 :

Final Round





1

2

3



4

5

YES

NO

Final assignment.

CLOCK PHASE

6

3 4 5 .. ..21 N 2 ..1 MM -1N -1

1

2

3

4

5

6

€/

$ /

¥

• The cloick auction is not cognitive per se– it is a mechanism to be exploited – it does not maximise auctioneer’s revenue– the auction mechanism yields efficient allocations

• A radio/network will only get economic and spectral efficiencies if it can plan/strategise/bid using sound reasoning:– current/historical prices– budget– intended services/revenues– quality of spectrum


No Cognition. No Efficiency.

Expression.• How does an engineer/telco talk to the market

when the regulator stops defining the offers?

1235

1515Bidder Y: I want to buy 30 MHz of spectrum,

with a centre frequency anywherebetween 1.25 GHz and 1.5 GHz

“I”

1000 2000Hz (x 1000)

30

Expression.



Bidder Z: I want to buy 30 MHz of spectrum,with a centre frequency anywhere

between 1.25 GHz and 1.5 GHz,

“I”

I”OR,“I want to buy 25 MHz of spectrum,with a centre frequency anywhere

between 1.6 GHz and 1.8 GHz,

“I”

1000 2000Hz (x 1000)

1235

1515

30

1587

.5

1812

.525



I”

Bidder P: I want to buy a PAIR of bands, each 20 MHz in width, with a 140 MHz separation between

the centre frequencies; those centre frequencies being located anywhere between 1.25 GHz and 1.75 GHz.

“

1000 2000Hz (x 1000)

1240

1760

20 20120



• How do CRs communicate with other CRs when there is no-one to define the offers?

Ba mhaith liom“ “. ”I WANT, I

WANT, I WANT“ “ ”

Je voudrais“ “. ”

T a ??e?a“ “ ”

Tim FoirdeCTVRTrinity College, University of Dublin, Ireland

A Combinatorial Cloic k Auction for OFDMA-based · 2008. 6. 10. · Linda Do iy le & Tim Fo ir de...

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