Blind Interference Alignment in General Heterogeneous Networks

TL;DR

This paper extends Blind Interference Alignment (BIA) to heterogeneous networks with macro and femtocells, proposing a generalized model that maximizes sum rate and achieves optimal Degrees of Freedom without requiring Channel State Information at the transmitters.

Contribution

It introduces a generalized BIA model for heterogeneous networks with macro and femtocells using Kronecker product representation, and proposes a beamforming solution to maximize sum rate and achieve optimal DoF.

Findings

Achieves optimal Degrees of Freedom over K+1 time slots.

Provides a beamforming strategy under power constraints.

Models BIA in heterogeneous networks with a Kronecker product approach.

Abstract

Heterogeneous networks have a key role in the design of future mobile communication networks, since the employment of small cells around a macrocell enhances the network's efficiency and decreases complexity and power demand. Moreover, research on Blind Interference Alignment (BIA) has shown that optimal Degrees of Freedom (DoF) can be achieved in certain network architectures, with no requirement of Channel State Information (CSI) at the transmitters. Our contribution is a generalised model of BIA in a heterogeneous network with one macrocell with K users and K femtocells each with one user, by using Kronecker (Tensor) Product representation. We introduce a solution on how to vary beamforming vectors under power constraints to maximize the sum rate of the network and how optimal DoF can be achieved over K+1 time slots.