%0 Journal Article
%T Generalized Degrees of Freedom of the Symmetric Gaussian $K$ User Interference Channel
%A Syed A. Jafar
%A Sriram Vishwanath
%J Mathematics
%D 2008
%I arXiv
%X We characterize the generalized degrees of freedom of the $K$ user symmetric Gaussian interference channel where all desired links have the same signal-to-noise ratio (SNR) and all undesired links carrying interference have the same interference-to-noise ratio, ${INR}={SNR}^\alpha$. We find that the number of generalized degrees of freedom per user, $d(\alpha)$, does not depend on the number of users, so that the characterization is identical to the 2 user interference channel with the exception of a singularity at $\alpha=1$ where $d(1)=\frac{1}{K}$. The achievable schemes use multilevel coding with a nested lattice structure that opens the possibility that the sum of interfering signals can be decoded at a receiver even though the messages carried by the interfering signals are not decodable.
%U http://arxiv.org/abs/0804.4489v1