Repeated Games For Inter-operator Spectrum Sharing - Bikramjit Singh, MSc Thesis Presentation, Aalto University, 2014 Thesis - http://arxiv.org/pdf/1505.04041v1.pdf Other works Coordination protocol for inter-operator spectrum sharing based on spectrum usage favors - http://arxiv.org/pdf/1505.02898v1.pdf Co-primary inter-operator spectrum sharing using repeated games - http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=7024767&queryText%3Dco-primary+sharing Co-primary inter-operator spectrum sharing using repeated games - http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=7024767&queryText%3Dco-primary+sharing Repeated spectrum sharing games in multi-operator heterogeneous networks - Coordination protocol for inter-operator spectrum sharing in co-primary 5G small cell networks - http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7158263&filter%3DAND%28p_IS_Number%3A7158253%29 Intermediate description of the spectrum needs and usage principles - https://www.metis2020.com/wp-content/uploads/deliverables/METIS_D5.1_v1.pdf

1. Repeated Games for Inter-operator
Spectrum Sharing
Bikramjit Singh
Supervisor: Prof. Olav Tirkkonen
Instructor: PhD. Konstantinos Koufos
Department of Communications and Networking (COMNET)
Aalto University, School of Electrical Engineering
Friday 24th
January, 2014

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Outline
Introduction
Background
Related Works
Related Standards
Cooperative Spectrum Sharing
Repeated Games based Spectrum Sharing
Proposed Model using Virtual Spectrum Price
Proposed Model using Mutual Gain/Loss History
Numerical Study
Conclusion and Future Works
References

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Introduction
1000 times traffic, 50 billion devices by 2020 [1,2]
16 billion LTE RAT users in 2018 [3]
Bandwidth requirements upto 1720 MHz for IMT by 2020 [4]
U.S. spectrum surplus/deficit per cell cite [5]

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Introduction
Summary frequency allocation 0.3-30 GHz
Spectrum utilization variations ranging from 15% to 85% [6]
Utilization of 0.5% in the 3-4 GHz and 0.3% in the 4-5 GHz
bands [7]
Less than 20% utilization in 3 GHz bands [8]
Problem is Spectrum Allocation not Physical Spectrum Scarcity

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Background
Interference management
How to tackle interference between peer-to-peer entities?
Utility
Represents the system’s performance level or QoS
A convex function
Game theory
To model interactions involving conflicting objectives
Game G invloving P number of players, their startegy profile
set S and utility function U, represented as, G = P, S, U

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Related Works
Cooperative games
Highest gains
Signalling overheads
Operators trust each other
Exchange information can be falsified
Repeated games
Operators can be hostile
Punishment mechanism
One-shot games
Poor Equilibria
Punishment too strict
Infinite Repeated games
Power domain
Spectrum related work involves monetary transactions

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Related Standards
IEEE 802.11 for Intra-cell/Inter-cell Transmission
Tackles intra/inter-cell transmission problems
IEEE 802.11h for Spectrum Management in 5 GHz Band
Only noisy 802.11h device adjusts its spectrum via DFS
IEEE 802.16h for Improved Coexisting Mechanism
Works in the time domain
IEEE 802.22 for using White Spaces in the TV Spectrum
Intended for centralized inter-network resource sharing
However, Inter-operator spectrum sharing is a non-centralized
implementation where all the operators participate and aim to
resolve inter-operator spectrum needs in the frequency domain

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Cooperative Spectrum Sharing
Motivation - P. Amin, O. Tirkkonen, T. Henttonen, and
E. Pernila, "Dynamic frequency selection based on carrier
pricing between cells," in Proc. IEEE VTC’13 Spring
System architecture

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Cooperative Spectrum Sharing
Cooperative decision mechanism for spectrum sharing
Operator Oi adds unused carrier k and compares its utility
gain Gi,k with operator O−i’s utility loss L−i,k
if Gi,k > L−i,k then
do START using carrier k
end if
Operator Oi removes used carrier k and compares its
utility loss Li,k with operator O−i’s utility gain G−i,k
if Li,k < G−i,k then
do STOP using carrier k
end if

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Repeated Games based Spectrum Sharing
System architecture
Game := Game(Utility, Decision, Check)
Spectrum usage favors
Operator STARTs using the CC alongside opponent
Opponent STOPs using the CC if asked by operator

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Proposed Model using Virtual Spectrum Price
Utility U, chosen as a function of cell throughput T and
virtual carrier price λ,
U = f(T) − λ
where, λ = p1(ep2K/K − 1), with p1 and p2 are pricing
constants, K and K are the numbers representing active
and full CC utilization
Decision, to a new carrier allocation startegy s adopted by
operator Oi, the following utility conditions must satisfy,
Oi : Ui,s > Ui O−i : U−i,s > U−i
Operators check the game by limiting spectrum usage
favors h against the maximal limit, surplus S,
Oi : h−i − hi ≤ S O−i : hi − h−i ≤ S

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Proposed Model using Mutual Gain/Loss History
Utility U, chosen as a function of cell throughput T,
U = f(T)
Decision, to a new carrier allocation startegy s adopted by
operator Oi, operator Oi compares immediate utility gain
Gi,s against expected loss Li,s, and operator O−i compares
immediate utility loss L−i,s against expected gain Gi,s
accordingly,
Oi : Gi,s > Li O−i : L−i,s < G−i
Operators check the game by limiting spectrum usage
favors h against the maximal limit, surplus S,
Oi : h−i − hi ≤ S O−i : hi − h−i ≤ S

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Numerical Study
10
1
10
2
10
3
0
0.2
0.4
0.6
0.8
1
User Rate (Mbps)
CDF
Orthogonal, Op. A
Orthogonal, Op. B
Full Spread, Op. A
Full Spread, Op. B
Cooperative, Op. A
Cooperative, Op. B
Prop., Op. A, S=2
Prop., Op. B, S=2
Figure: Rate distribution for operator Oa, Na = 25 users and operator
Ob, Nb = 5 users using various schemes in a high interference
environment. The maximum number of outstanding favors, S = 2.

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Numerical Study
10
1
10
2
10
3
0
0.2
0.4
0.6
0.8
1
User Rate (Mbps)
CDF
Orthogonal
Full Spread
Cooperative
Prop., S=2
Figure: Rate distribution for operator Oa with temporal load variations
(for first half of simulations with Na = 25 users and the second half
with Na = 5 users) using various schemes in a high interference
environment. The maximum number of outstanding favors, S = 2.

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Numerical Study
10
1
10
2
10
3
0
0.2
0.4
0.6
0.8
1
User Rate (Mbps)
CDF
Cooperative
Prop., S=2
Prop., S=4
Figure: Rate distribution for operator Oa, Na = 25 users using various
schemes in a high interference environment. The maximum number
of outstanding favors is varied and rate curves are analysed for,
S = 2 and 4.

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Conclusion
Investigated the impact of noncooperative games between the
operators on spectrum sharing
Properly modelled games provide a clear gain over full spread
and orthogonal spectrum sharing
Gains are significant when the number of serving users by an
operator is relatively large
Future Works
Cooperative schemes for intra-operator radio resource
management
Using outstanding favors in the decision making process
Load prediction

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References
[1] "Wake-up call: Industry collaboration needed to make beyond 4G networks carry
1000 times more traffic by 2020," White Paper, Nokia Siemens Networks, Aug. 2011.
[2] "More than 50 billion connected devices," White Paper, Ericsson, Feb. 2011.
[3] "LTE release 12 - taking another step toward the networked society," White Paper,
Ericsson, Jan. 2013.
[4] "Estimated spectrum bandwidth requirements for the future development of
IMT-2000 and IMT-Advanced," International Telecommunication Union ITU, Tech. Rep.
M.2078.
[5] Federal Communications Commission FCC, Tech. Rep., Feb. 2012.
[6] "First report and order in the matter of revision of part 15 of the commission’s rules
regarding ultra wideband transmission systems," Federal Communications
Commission FCC, FCC 02-48 ET Docket 98-153, Feb. 2002.
[7] D. ˇCabri´c, S. M. Mishra, and R. W. Brodersen, "Implementation issues in spectrum
sensing for cognitive radios," in Proc. Asilomar Conference on Signals, Systems and
Computers (ASILOMAR’04), Nov. 2004, pp. 772-776.
[8] V. Valenta, R. Maršálek, G. Baudoin, M. Villegas, M. Suarez, and F. Robert, "Survey
on spectrum utilization in europe: Measurements, analyses and observations," in Proc.
IEEE International Conference on Cognitive Radio Oriented Wireless Networks
(CROWNCOM’10), Jun. 2010, pp. 1-5.

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Thank You