Symmetric K-user Gaussian interference channels: Approximate sum-capacity via deterministic modeling

Linear deterministic interference channel models approximate Gaussian channels when the signal-to-noise ratio is high. Exact analysis of the former has in some cases yielded approximate capacity results in the latter, like the 2-user interference channel or the relay channel. Here, we follow a similar program for K-user symmetric interference channels. Specifically, we translate achievable strategies for the deterministic case derived in an earlier paper to the Gaussian case using nested lattice codes. In this case, the approximation gap depends on the channel parameters and becomes unbounded in certain regimes.