The Degrees of Freedom of MIMO Interference Channels without State Information at Transmitters

Understand

This paper fully determines the degree-of-freedom (DoF) region of two-user interference channels with arbitrary number of transmit and receive antennas and isotropic fading, where the channel state information is available to the receivers but not to the transmitters.

• The result characterizes the capacity region to the first order of the logarithm of the signal-to-noise ratio (SNR) in the high-SNR regime.
• The DoF region is achieved using random Gaussian codebooks independent of the channel states.
• Hence the DoF gain due to beamforming and interference alignment is completely lost in absence of channel state information at the transmitters (CSIT).