The Information-Theoretic Constant-Gap Optimality of Treating Interference as Noise in Interference Networks

Abstract

Treating interference as noise is one of the simplest methods for the management of interference in wireless networks. Despite its simplicity, treating interference as noise (TIN) was shown to be information-theoretically optimal for certain Gaussian interference channels (IC) with very-weak (noisy) interference. In this chapter, we consider cellular networks, such as networks that consists of a point-to-point channel interfering with a multiple access channel (MAC). The sum-capacity of such networks is studied with main focus on the constant-gap optimality of TIN rather than on its exact optimality. It turns out that TIN in its naive variant, where all transmitters are active and receivers use TIN for decoding, is not the best choice for certain networks. In fact, a scheme that combines both time division multiple access and TIN (TDMA-TIN) strictly outperforms the naive TIN scheme. Furthermore, it is shown that in some regimes, TDMA-TIN achieves the sum-capacity within a constant gap for Gaussian networks. Additionally, it is shown that, even for very-weak interference, there are some regimes where a combination of interference alignment with power control and treating interference as noise at the receiver side outperforms TDMA-TIN. As a consequence, on the one hand treating interference as noise in a cellular uplink is approximately optimal in certain regimes. On the other hand, those regimes cannot be simply described by the strength of interference, requiring a careful design of wireless networks.