An optimized cooperative interference alignment algorithm for MIMO interference channel

Interference alignment is a kind of transmission technique which is able to align the interference from other transmitters into the same channel space. This paper proposes a novel optimized cooperative interference alignment (IA) scheme for a K user Multiple Input Multiple Output (MIMO) M × M interference channel (IC). In order to maximized decrease the effect of the interference from unwanted transmitters, we will not only choose a group of optimized eigen-channels to transport the signals, but also select a group of precoding vectors to leave the desired signal away from interference, which are based on the decomposition of channel and the chord distance of matrix. What is more, we also design the interference suppress matrix using the optimized precoding matrix. The cooperative algorithm in this paper not use the iterative to get the precoding matrix or the suppress matrix so that it minimizes the complexity of the whole system. Further, the results of simulation show that it obviously improves both the capacity and the energy efficiency by this optimized algorithm, which also accord with the green communication.

I. Introduction

In an interference channel, each transmitter desires to communicate information with its intended receiver, in the presence of interference from other user pairs, as the broadcast nature of wireless channel. Interference alignment is a technique to align the interference from other user pairs to a subspace of received signal, which called interference subspace, and to keep the interference subspace and the desired signal subspace linearly independent.