Improvement of a MIMO antenna structure with combination of transmit beamforming and spatial multiplexing

Downlinks of the cellular systems generally have more transmit antennas than receive antennas. To efficiently exploit all antenna resources, a technique that combines the advantage of beamforming and spatial multiplexing has been proposed, which partitions the transmit antennas into neighboring sub-groups. In this article, this technique is further improved by Eq. (1) allowing non-contiguous antenna grouping, and Eq. (2) adopting two new grouping criteria: minimum signal distance maximization (MSDM) criterion and maximum correlation coefficient minimization (MCCM) criterion. Simulation results indicate that these improvements can bring noticeable gains in the Rayleigh flat fading channel environment.