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Gaussian Interference Networks: Sum Capacity in the Low Interference Regime and New Outer Bounds on the Capacity Region (0802.3495v2)

Published 24 Feb 2008 in cs.IT and math.IT

Abstract: Establishing the capacity region of a Gaussian interference network is an open problem in information theory. Recent progress on this problem has led to the characterization of the capacity region of a general two user Gaussian interference channel within one bit. In this paper, we develop new, improved outer bounds on the capacity region. Using these bounds, we show that treating interference as noise achieves the sum capacity of the two user Gaussian interference channel in a low interference regime, where the interference parameters are below certain thresholds. We then generalize our techniques and results to Gaussian interference networks with more than two users. In particular, we demonstrate that the total interference threshold, below which treating interference as noise achieves the sum capacity, increases with the number of users.

Citations (455)

Summary

  • The paper derives improved outer bounds on the capacity region using advanced genie-aided arguments, offering a tighter characterization than previous models.
  • It demonstrates that treating interference as noise attains the sum capacity in low interference regimes for both symmetric and asymmetric channels.
  • The research extends the analysis to multi-user networks by introducing a 'vector genie' method, providing robust guidelines for interference management in wireless systems.

Analysis of Gaussian Interference Networks in Low Interference Regimes

The paper "Gaussian Interference Networks: Sum Capacity in the Low Interference Regime and New Outer Bounds on the Capacity Region" by V. Sreekanth Annapureddy and Venugopal V. Veeravalli presents a thorough investigation into the capacity regions of Gaussian interference networks, specifically targeting the low interference regime. The paper leverages mathematical tools from information theory to derive new outer bounds and examines the efficacy of treating interference as noise in achieving sum capacity, with particular attention given to systems involving two or more users.

Key Contributions

The primary objective of this paper is to elucidate the capacity region for Gaussian interference networks, an ongoing challenge in information theory. The paper makes several notable contributions:

  • Derivation of New Outer Bounds: The authors develop improved outer bounds on the capacity region using genie-aided arguments. The incorporation of generalized genie signals introduces a versatile class of constraints that enhance the bounding process's robustness. These bounds are significant as they provide a tighter characterization of the capacity region compared to existing bounds in the literature.
  • Sum Capacity in Low Interference Regimes: A crucial result of the paper is that treating interference as noise can achieve the sum capacity in a low interference "regime." This is established for both symmetric and asymmetric interference channels, providing conditions under which this treating interference strategy becomes optimal.
  • Applications to Networks with Multiple Users: Extending the analysis to Gaussian networks beyond two users, the paper proposes conditions for treating interference as noise in many-to-one and one-to-many interference channels, characterizing these settings' sum capacity limits. This generalization is realized through constructing a "vector genie," offering a systematic method of generating multiple side information signals for each receiver, thus broadening applicability to larger networks.

Implications and Future Directions

The implications of this research are multifaceted. Practically, the results offer guidelines for designing interference management strategies in wireless networks where links experience low interference. Theoretically, the introduction of new bounding techniques and genie-aided arguments provides a fertile ground for further exploration into more complex network configurations.

Looking forward, several avenues could benefit from this paper’s insights. Notably, understanding how the interference threshold, below which treating interference as noise is optimal, scales with increasing network size remains an open question. Exploring tighter bounds or alternative strategies in networks experiencing higher interference could provide additional layers of optimization.

Concluding Thoughts

This paper effectively addresses a critical gap in the understanding of Gaussian interference networks, augmenting present methodologies with robust mathematical frameworks to determine capacity regions in low interference settings. The strategic use of information-theoretic tools to derive meaningful results positions this paper as a significant contribution to the field of wireless communications and network theory.