On the Optimality of Treating Interference as Noise: A New Link Scheduling and Power Control for D2D Communications

Abstract

For single-antenna Gaussian interference channels, we consider the problem of the Generalized Degrees of Freedom (GDoF) region achievable by treating Interference as Gaussian nNoise (TIN). We show that the TIN power control problem can be cast into an assignment problem, such that the globally optimal power allocation variables can be obtained by well-known polynomial time algorithms (e.g., centralized Hungarian method or distributed Auction algorithm). Furthermore, a previously known expression of the TIN-Achievable GDoF region (TINA region) can be substantially simplified with the aid of maximum weighted matchings. We also provide conditions under which the TINA region is a convex polytope. Building on the above insights, we consider the problem of joint link scheduling and power control in wireless networks, which has been widely studied as a basic physical layer mechanism for device-to-device (D2D) communications. The idea is to select at each scheduling slot a subnetwork for which the TINA region is a convex polytope, and then optimize the transmit power of the selected links in order to maximize the corresponding weighted sum rate.

We propose a low-complexity GDoF-based distributed link scheduling and power control mechanism (ITLinQ+) that improves upon previously proposed schemes, including the powerful heuristic approach of Qualcomm known as FlashLinQ. More notably, the energy efficiency of the newly proposed ITLinQ+ scheme is substantially larger than that of FlashLinQ. This feature is particularly desirable for D2D networks formed by battery-powered devices.