The Generalized Degrees of Freedom Region of the MIMO Interference Channel
Abstract
The generalized degrees of freedom (GDoF) region of the MIMO Gaussian interference channel (IC) is obtained for the general case of an arbitrary number of antennas at each node and where the signaltonoise ratios (SNR) and interferencetonoise ratios (INR) vary with arbitrary exponents to a nominal SNR. The GDoF region reveals various insights through the joint dependence of optimal interference management techniques (at high SNR) on the SNR exponents that determine the relative strengths of directlink SNRs and crosslink INRs and the numbers of antennas at the four terminals. For instance, it permits an indepth look at the issue of ratesplitting and partial decoding and it reveals that, unlike in the scalar IC, treating interference as noise is not always GDoFoptimal even in the very weak interference regime. Moreover, while the DoFoptimal strategy that relies just on transmit/receive zeroforcing beamforming and timesharing is not GDoF optimal (and thus has an unbounded gap to capacity), the precise characterization of the very strong interference regime  where singleuser DoF performance can be achieved simultaneously for both users depends on the relative numbers of antennas at the four terminals and thus deviates from what it is in the SISO case. For asymmetric numbers of antennas at the four nodes the shape of the symmetric GDoF curve can be a "distorted W" curve to the extent that for certain MIMO ICs it is a "V" curve.
 Publication:

arXiv eprints
 Pub Date:
 March 2011
 arXiv:
 arXiv:1103.2560
 Bibcode:
 2011arXiv1103.2560K
 Keywords:

 Computer Science  Information Theory
 EPrint:
 38 pages, 14 figures. Submitted to Trans. of IT