Elevation beamforming with beamspace methods for LTE

Recently, there has been interest in extending MIMO processing techniques to exploit the elevation dimension of the multipath channel in addition to the azimuth dimension. In this paper, we explore the use of beamspace methods for creating virtual antenna ports in the vertical direction to enable a base station antenna array to exploit the elevation dimension of the multipath channel. We consider two ways of configuring the vertical antenna array: vertical sectorization, which creates additional sectors in the vertical domain, and vertical beamforming, which simply leverages the additional vertical antenna ports with existing MIMO processing techniques. For Rel-8/10 LTE, we show that both vertical sectorization and vertical beamforming can provide significant gains in the average and cell-edge throughputs, both in full buffer traffic as well as bursty traffic. We also highlight the sensitivity of the results to the specific assumptions of the underlying multipath channel characteristics and other system parameters.