Perfect interference alignment utilizing channel structure

Abstract

Interference alignment (IA) is a transmission strategy that attempts to exploit all degrees of freedom available at the transmitter or at the receiver in a multiuser channel. This paper proposes a new scheme named channel aided interference alignment. It makes use of the channel structure beside the linear interference alignment schemes to achieve the optimum degrees of freedom in a K user interference channel. In case the channel matrix does meet the specified structure, the proposed scheme achieves the optimum degrees of freedom at a finite signal to noise ratio and by using limited number of channel realizations; it turns to the usual linear vector interference alignment schemes otherwise. For the case of 3 user interference channel, it would be shown that if only one of interfering channel coeficients can be designed to a specific value, interferenfce would be aligned perfectly at all the receivers.