The degrees of freedom region of the MIMO cognitive interference channel with no CSIT

The cognitive interference channel (C-IC) is defined as the interference channel that consists of two transmitter-receiver pairs and in which any one or more of the four terminals is cognitive. The degrees of freedom (dof) region of the C-IC is studied for the case in which there is perfect and no channel state information at the receivers and the transmitters, respectively. The proposed inner and outer-bounds yield the precise characterization of dof region, except for a few cases of cognition in which for certain values of the number of antennas at the four terminals, the bounds are not tight. Finally, an example on the feasibility of interference alignment without transmitter knowledge of the channel realizations is shown.