Impact of Radiation Pattern Control of MIMO Antenna on Interfered Multicell Environment

Abstract

This letter proposes an improved method of maximizing the achievable rate using analog radiation pattern control combined with transmit beamforming in multiple-access-point (AP) environments; it is evaluated by measurements. As the AP antennas, tunable beamwidth antennas using parasitic antennas loaded by varactor diodes are used. $4 \times 4$ multiple-input–multiple-output (MIMO) channels are measured in an actual indoor environment, where two sets of cells exist. It is shown that the proposed method is effective in enhancing the achievable rate for multiple-AP environment.