Full-Dimension MIMO Arrays with Large Spacings Between Elements

Full-Dimension MIMO is identified as a promising MIMO technique for next cellular standards. It is based on performing beamforming not only in the azimuth but also in the elevation dimension. In this paper, it is studied how the beamforming performance can be enhanced by increasing the spacing between antenna elements. The major claims are that the system capacity can be enhanced by increasing the antenna spacing until the limit in which the grating lobes start falling inside the desired sector. For larger spacings, the benefits of reduced beamwidths are cancelled out by the interference introduced by grating lobes

Antenna array configurations for massive MIMO outdoor base stations

Massive MIMO predicts unprecedented capacity and energy efficiency improvements in future networks, by the use of base stations with hundreds of antennas. However the crucial question of determining suitable, or even optimal, antenna hardware solutions for deploying such a large number of antennas in constrained physical spaces is still open. Here we analyse the potential benefits of using compact arrays, dual-polarized arrays, and 2D arrays in outdoor scenarios using a realistic 3D spatial channel model and accurate antenna electromagnetic simulations. In particular we show that it is detrimental to reduce the distance between elements below ¿/3. Actually, better performances can be achieved by increasing the number of antennas using dual polarization instead (if random polarization of user antennas is assumed). We also show that good performance can be achieved by using 2D arrays, but at the expense of an increased number of total elements when compared to horizontal linear arrays. © 2014 IEEE.Peer ReviewedPostprint (published version

Antenna array configurations for massive MIMO outdoor base stations

Massive MIMO predicts unprecedented capacity and energy efficiency improvements in future networks, by the use of base stations with hundreds of antennas. However the crucial question of determining suitable, or even optimal, antenna hardware solutions for deploying such a large number of antennas in constrained physical spaces is still open. Here we analyse the potential benefits of using compact arrays, dual-polarized arrays, and 2D arrays in outdoor scenarios using a realistic 3D spatial channel model and accurate antenna electromagnetic simulations. In particular we show that it is detrimental to reduce the distance between elements below ¿/3. Actually, better performances can be achieved by increasing the number of antennas using dual polarization instead (if random polarization of user antennas is assumed). We also show that good performance can be achieved by using 2D arrays, but at the expense of an increased number of total elements when compared to horizontal linear arrays. © 2014 IEEE.Peer Reviewe