Optimal spectrum management in two-user symmetric interference channels

In this paper, we solve for the optimal spectrum management of the sum-rate maximization problem in two-user symmetric interference channels. A sum-power constraint, or equivalently, equal power constraints are assumed. First, by solving a closed form equation, we explicitly obtain the optimal spectrum management in flat channels as an optimal combination of flat FDMA and flat frequency sharing, exploiting the fact that all spectrum management schemes are built with these two basic co-existence strategies. Based on this result, we show that the non-convex optimization over the spectrum and power allocation in frequency selective channels can be equivalently transformed into a convex optimization in the primal domain.