Capacity bounds for the Gaussian interference channel

  • Authors:

  • Abolfazl Seyed Motahari;Amir Keyvan Khandani

  • Affiliations:

  • Coding and Signal Transmission Laboratory, Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON, Canada;Coding and Signal Transmission Laboratory, Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON, Canada

  • Venue:
  • IEEE Transactions on Information Theory
  • Year:
  • 2009

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Abstract

The capacity region of the two-user Gaussian interference channel (IC) is studied. Three classes of channels are considered: weak, one-sided, and mixed Gaussian ICs. For the weak Gaussian IC, a new outer bound on the capacity region is obtained that outperforms previously known outer bounds. The sum capacity for a certain range of channel parameters is derived. For this range, it is proved that using Gaussian codebooks and treating interference as noise are optimal. It is shown that when Gaussian codebooks are used, the full Han-Kobayashi achievable rate region can be obtained by using the naive Han-Kobayashi achievable scheme over three frequency bands (equivalently, three subspaces). For the one-sided Gaussian IC, an alternative proof for the Sato's outer bound is presented. We derive the full Han-Kobayashi achievable rate region when Gaussian codebooks are utilized. For the mixed Gaussian IC, a new outer bound is obtained that outperforms previously known outer bounds. For this case, the sum capacity for the entire range of channel parameters is derived. It is proved that the full Han-Kobayashi achievable rate region using Gaussian codebooks is equivalent to that of the one-sided Gaussian IC for a particular range of channel parameters.