The Generalized Degrees of Freedom of the

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Chair of Digital Communication Systems

The Generalized Degrees of Freedom of the Interference Relay Channel with Strong Interference Soheyl Gherekhloo, Anas Chaaban, Aydin Sezgin

October 03, 2013

S. Gherekhloo, A. Chaaban, A. Sezgin

The GDoF of the IRC with Strong Interference

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Contents

1 GDoF of the IC

2 GDoF of the IRC

3 Achievability Scheme



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Interference Channel (IC)



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• Channels are real



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• Channels are real • Power constraint at each node: P



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• Channels are real • Power constraint at each node: P

α=


log(P h2c ) log(P h2d )


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α=




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α=


Definition GDoF =

sum-capacity 1 P h2d →∞ 2 log(P h2 d) lim



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W Curve [Etkin, Tse, Wang, 08]



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Interference Relay Channel (IRC)



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Question: What is the impact of relay on the GDoF?



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GDoF of the IRC

4.5 4 3.5

d

3 2.5 2 Old upper bound for the IRC New upper bound for the IRC IC

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GDoF of the IRC 4.5 4 3.5

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d


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d


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Main Result

Theorem The GDoF of the IRC with 1 < α < γ is given by   2 max{1, β}       max{α, β} + γ − α GDoF = min γ+α       α+β S. Gherekhloo, A. Chaaban, A. Sezgin


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d


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d


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• α < γ2 ⇒ Relay can have a better observation. S. Gherekhloo, A. Chaaban, A. Sezgin


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Channel to the Relay α