Sum Degrees of Freedom for the K-user Interference Channel Using Antenna Switching

Abstract

In this paper, we consider the problem of interference alignment (IA) for the $K$-user SISO interference channel (IC) with no channel state information (CSI) at transmitters. Contrary to the traditional $K-$user interference alignment (IA) scheme introduced by Cadambe and Jafar, our achievement has more practical aspects. In the present work, each transmitter uses a specific precoder and every receiver is equipped with one reconfigurable antenna. Each pair of transceivers with the aid of a specific precoder and a switching pattern structure tries to place its desired signal in a subspace which is linearly independent of interference signals. The result of this paper indicates that the optimum sum DoF for the $K-$user IC with an asymptotically large interference network is $\frac{\sqrt{K}}{2}$.