Entry game under opportunistic access in cognitive radio networks: a priority queue model

8/9/2019 Entry game under opportunistic access in cognitive radio networks: a priority queue model

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Entry game under opportunistic access in cognitive radio networks: a priority queue model

Entry game under opportunistic access in

cognitive radio networks: a priority queue

model

Luis Guijarro1 Vicent Pla1 Bruno Tuffin2

1Universitat Politecnica de Valencia, Spain

2INRIA, France

Wireless Days, Valencia, November 2013

TELPOL92
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Contents

Model

Analysis

Results and discussion

Conclusions

Guijarro et al. 2/17
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Model

Contents

Model

Analysis


Conclusions

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Model

Scenario

Cognitive radio networks

Primary operator is the incumbent and holds a spectrum

license

Secondary operator is the entrant and does not hold a licenseOpportunistic access

it is granted by the primary operator to the secondary

operator

Secondary operator coordinates access from itssubscribers. They do not cause a significant impact in the

QoS received by primary, apart from failures due to

sensing limitations and delays



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Model

Service model

M/M/1 Priority Queue

Primary (resp. secondary)

packets arrive according to

a Poisson process at rate

1 (resp. 2) and arequeued in the priority

(resp. ordinary) queue

Failures in the

opportunistic accessmodeled as

non-preemptive variation

The transmission time of all packets is exponentially distributed

with meanx= 1/Guijarro et al. 5/17
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Model

Economic model

Operator icharges a

per-packet pricepi

Primary packets payp1

Secondary packets payp2

Operator is profits

i= ipi=

ixp

i.

Per-packet utility

ui Qi pi

Qi= c T

i

Tiis the mean service time

0<


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Model

Game model

Two-stage sequential game. Multi-leader-follower

Second stage: subscription

Given that u


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Analysis

Contents

Model

Analysis


Conclusions

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Analysis

Monopoly

AnM/M/1 queue

Q() = c

x

1

Equilibrium equations

Q() p= 0.

p=

p

xp= 0.

Equilibrium solution

m= 1

1 +

pm= cx

1 +

.

m= cx(1+)

(1 + )1+.

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Analysis

Duopoly

A non-preemptive priorityM/M/1 queue

Q1(1, 2) =c

1+ 21 1

x

Q2(1, 2) =c

1

1(1

(1+ 2))(1 1)(1 (1+ 2))

x

Equilibrium equations

Qi(1, 2) pi= 0 i= 1, 2

ipi

= pi

ix

pi= 0 i= 1, 2

Equilibrium solution

1 =

1

1+

2 =1+ 21 +2

21

1+ 2 41 +4

21+2

21

Alsop1, p2,1,2

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Contents

Model

Analysis


Conclusions


E t d t i ti i iti di t k i it d l
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Equilibrium traffic

Facts

1 = m

As increases, the

monopolist, and the primaryoperator, is able to carry lesstraffic. The secondaryoperator carries more traffic.The total traffic decreases

Analysis The entry of the secondary

operator is desirable from anefficiency perspective

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

m

1

2

1+

2

x= 1 andc= 1


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Equilibrium profits

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

m

1

2

1+

2

x= 1 andc= 1

Facts

1 m

As increases, themonopolist, and the primary

operator, obtains less profits.The secondary operatorsprofit increases only up to 0.25

Analysis

The primary operator suffersa decrease in profits when asecondary operator entersthe market


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Entry analysis

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

m

1

2

1+

2

x= 1 andc= 1

Lump sum paymentm

Incentives for primaryoperator 1 + m m

Incentives for secondaryoperator 2 m 0

Or, equivalently, 1 + 2 mFacts

This condition is fulfilled for arange of values of up to 0.65.


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Capacity leasing

The incumbent leases capacity

2 to the entrant operator, andkeeps1= 2Modelled as two independentM/M/1 queuesEquilibrium traffic and profits

result in

(1 + 2)x= m

1 + 2 m


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Conclusions

Contents

Model

Analysis


Conclusions


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Conclusions

1. The economic viability of supporting the secondary

operator service using an opportunistic access to the

spectrum owned by the primary operator has been

assessed.

2. Against the benchmark of the primary operator operating

as a monopolist, we conclude that the entry of thesecondary operator is desirable from an efficiency

perspective, since the carried traffic increases.

3. Additionally, for a range of parameter values, a lump sum

payment can be designed so that the incumbent operator

has an incentive to let the secondary operator enter.

4. The opportunistic access setting has been compared

against a leasing-based alternative, and we have

concluded that the former outperforms the latter.


Documents

Entry game under opportunistic access in cognitive radio networks: a priority queue model