On the Implementation of Blind Interference Alignment with Single-Radio Parasitic Antennas

This paper studies the electronically steerable parasiticarray radiator (ESPAR) antenna as a solution for beampatternswitching to implement blind interference alignment (BIA)[1]. The ESPAR antenna uses a single radio-frequency (RF) chain,and its beamforming is achieved by simply tuning the reactanceloads of parasitic elements. Furthermore, ESPAR’s beampatterncan be designed to enhance the received signal-to-noise ratio(SNR), thereby improving the performance of BIA. The focus ofthis work is the design of the ESPAR beampattern to realize andimprove BIA. In the first approach, each receiver ESPAR antennadynamically selects the proper beampatterns from among thesector beampatterns, which are pre-designed to access differentangular sectors with constant optimal antenna efficiency. Wealso propose a singular value decomposition (SVD) beamformingmethod, by means of the available channel state information atthe receiver and a dynamic matching network for a high antennaefficiency. The simulation results illustrate the improvement ofBIA with proposed methods, especially in the low and moderateSNR region, due to ESPAR’s beamforming capability.