Interference Alignment for the <i>K</i>-User MIMO Interference Channel

We consider the $K$ -user Multiple Input Output (MIMO) Gaussian interference channel with notation="LaTeX">$M$ antennas at each transmitter and notation="LaTeX">$N$ receiver. It is assumed that coefficients are constant real numbers available all transmitters receivers. The main objective of this paper to characterize number Degrees Freedom (DoF) channel. Using alignment technique introduced in Motahari et al. , 2014, we show notation="LaTeX">$\frac {MN}{M+N} K$ degrees freedom can be achieved for almost realizations. Also, a new upper-bound on DoF provided. This coincides our achievable notation="LaTeX">$K\geq K_{u} \triangleq \frac {M+N}{\gcd (M,N)}$ where notation="LaTeX">$\gcd (M,N)$ denotes greatest common divisor . gives an exact characterization notation="LaTeX">$M\times N$ MIMO case K_{u}$ Since there no cooperation between transmit (or receive) user transmission scheme, result shows benefit joint processing collocated vanishes when users greater than certain threshold.