An Achievable Rate Region for the Gaussian Interference Channel

An achievable rate region for the Gaussian interference channel is derived using Sato's modified frequency division multiplexing idea and a special case of Han and Kobayashi's rate region (denoted by $\Gmat^\prime$). We show that the new inner bound includes $\Gmat^\prime$, Sason's rate region $\Dmat$, as well as the achievable region via TDM/FDM, as its subsets. The advantage of this improved inner bound over $\Gmat^\prime$ arises due to its inherent ability to utilize the whole transmit power range on the real line without violating the power constraint. We also provide analysis to examine the conditions for the new achievable region to strictly extend $\Gmat^\prime$.