Optimal Spectrum Management in Two-User Interference Channels

TL;DR

This paper investigates optimal spectrum management in multiuser interference channels, proving that users should transmit at maximum power in frequency-selective channels and providing an optimal solution for two-user flat channels.

Contribution

It establishes that maximum power usage is optimal in frequency-selective channels and offers an exact solution for two-user flat channels.

Findings

Maximum power usage is optimal in frequency-selective channels.

Optimal solution derived for two-user flat channels.

Results extend to proportional fairness objectives.

Abstract

In this work, we address the problem of optimal spectrum management in continuous frequency domain in multiuser interference channels. The objective is to maximize the weighted sum of user capacities. Our main results are as follows: (i) For frequency-selective channels, we prove that in an optimal solution, each user uses maximum power; this result also generalizes to the cases where the objective is to maximize the weighted product (i.e., proportional fairness) of user capacities. (ii) For the special case of two users in flat channels, we solve the problem optimally.