On the Optimality of Treating Interference as Noise

Abstract

It is shown that in the K-user interference channel, if for each user the desired signal strength is no less than the sum of the strengths of the strongest interference from this user and the strongest interference to this user (all values in dB scale), then the simple scheme of using point to point Gaussian codebooks with appropriate power levels at each transmitter and treating interference as noise at every receiver (in short, TIN scheme) achieves all points in the capacity region to within a constant gap. The generalized degrees of freedom (GDoF) region under this condition is a polyhedron, which is shown to be fully achieved by the same scheme, without the need for time-sharing. The results are proved by first deriving a polyhedral relaxation of the GDoF region achieved by TIN, then providing a dual characterization of this polyhedral region via the use of potential functions, and finally proving the optimality of this region in the desired regime.

Superposition Signaling in Broadcast Interference Networks

“…A similar result for the K-user cyclic GIN was obtained in [18]. It was also shown in [19]- [21] that using non-Gaussian inputs (or in [22] with Gaussian inputs) and treating interference as noise achieves the capacity region of some special SISO GINs within a constant gap. The withinconstant-gap results have a merit in the high signal-to-noise ratio (SNR) regime only, where the achievable rate region is sufficiently large.…”

Extended generalized DoF optimality regime of treating interference as noise in the X channel

“…TIN is constant-gap optimal in the symmetric K-user IC (K > 2) under the same condition [7]. This result has been extended for asymmetric Kuser IC in [8]. The optimality of TIN has also been studied for scenarios in which numbers of transmitters and receivers are not equal [9].…”

Cognitive blind interference alignment for macro-femto cellular networks

“…Therefore, only some synchronization between the Macro BS and the FAPs is required. On the other hand, femtocells far from the Macro BS can treat interference as noise due to path losses [9]. The proposed scheme does not cause any rate loss to macrocell users, which achieve the maximum DoF attainable without CSIT.…”