PhD Defense: “Noisy Channel-Output Feedback in the Interference Channel” by Victor Quintero, 12th of December 2017, at 14h, in the amphitheater Émilie du Châtelet – Marie Curie Library – INSA de Lyon

Jury

  • Prof. Michèle WIGGER, Reviewer, Télécom Paristech, France.
  • Prof. Abdellatif ZAIDI, Reviewer, Université Paris-Est Marne la Vallée, France.
  • Prof. Inbar FIJALKOW, Examiner, Université de Cergy-Pontoise, France.
  • Prof. H. Vincent POOR, Examiner, Princeton University, USA.
  • Prof. Gerhard KRAMER, Examiner, Technische Universität München, Germany.
  • Prof. David GESBERT, Examiner, Eurecom, France.
  • Prof. Jean-Marie GORCE, Thesis Director, Université de Lyon, France.
  • Dr. Samir M. Perlaza, Thesis Advisor, INRIA, France.
  • Prof. Iñaki Esnaola, Guest, University of Sheffield, UK.

Abstract
In this thesis, the two-user Gaussian interference channel with noisy channel-output feedback (GIC-NOF) is studied from two perspectives: centralized and decentralized networks.

From the perspective of centralized networks, the fundamental limits of the two-user GIC- NOF are characterized by the capacity region. One of the main contributions of this thesis is an approximation to within a constant number of bits of the capacity region of the two-user GIC-NOF. This result is obtained thanks to the analysis of a simpler channel model, i.e., a two-user linear deterministic interference channel with noisy channel-output feedback (LDIC- NOF). The analysis to obtain the capacity region of the two-user LDIC-NOF provides the main insights required to analyze the two-user GIC-NOF.

From the perspective of decentralized networks, the fundamental limits of the two-user decentralized GIC-NOF (D-GIC-NOF) are characterized by the η-Nash equilibrium (η-NE) region. Another contribution of this thesis is an approximation to the η-NE region of the two-user GIC-NOF, with η > 1. As in the centralized case, the two-user decentralized LDIC-NOF (D-LDIC-NOF) is studied first and the lessons learnt are applied in the two-user D-GIC-NOF. The final contribution of this thesis consists of a closed-form answer to the question: “When does channel-output feedback enlarge the capacity or η-NE regions of the two-user GIC-NOF or two-user D-GIC-NOF?”. This answer is of the form: Implementing channel-output feedback in transmitter-receiver i enlarges the capacity or η-NE regions if the feedback SNR is beyond SNRi*, with i∈{1,2}. The approximate value of SNRi* is shown to be a function of all the other parameters of the two-user GIC-NOF or two-user D-GIC-NOF.