Aiming Perfectly in the Dark - Blind Interference Alignment through Staggered Antenna Switching

TL;DR

This paper introduces a blind interference alignment method for vector broadcast channels using reconfigurable antennas, achieving high degrees of freedom without channel knowledge at the transmitter or receivers.

Contribution

It presents a novel blind interference alignment scheme utilizing reconfigurable antennas and short-term channel fluctuations, applicable without channel state information at the transmitters or receivers.

Findings

Achieves MK/(M+K-1) degrees of freedom.

Does not require channel knowledge at transmitters or receivers.

Applicable to MxK X networks with finite symbol extensions.

Abstract

We propose a blind interference alignment scheme for the vector broadcast channel where the transmitter is equipped with M antennas and there are K receivers, each equipped with a reconfigurable antenna capable of switching among M preset modes. Without any knowledge of the channel coefficient values at the transmitters and with only mild assumptions on the channel coherence structure we show that MK/M+K-1 degrees of freedom are achievable. The key to the blind interference alignment scheme is the ability of the receivers to switch between reconfigurable antenna modes to create short term channel fluctuation patterns that are exploited by the transmitter. The achievable scheme does not require cooperation between transmit antennas and is therefore applicable to the MxK X network as well. Only finite symbol extensions are used, and no channel knowledge at the receivers is required to null the interference.