Downlink beamforming in Massive MIMO either relies on uplink pilot measurements - exploiting reciprocity and TDD operation, or on the use of a predetermined grid of beams with user equipments reporting their preferred beams, mostly in FDD operation. Massive MIMO in its originally conceived form uses the first strategy, with uplink pilots, whereas there is currently significant commercial interest in the second, grid-of-beams. It has been analytically shown that in isotropic scattering (independent Rayleigh fading) the first approach outperforms the second. Nevertheless there remains controversy regarding their relative performance in practice. In this contribution, the performances of these two strategies are compared using measured channel data at 2.6 GHz.
@article{arxiv.1704.00623,
title = {Massive MIMO Performance - TDD Versus FDD: What Do Measurements Say?},
author = {Jose Flordelis and Fredrik Rusek and Fredrik Tufvesson and Erik G. Larsson and Ove Edfors},
journal= {arXiv preprint arXiv:1704.00623},
year = {2017}
}
Comments
Submitted to IEEE Transactions on Wireless Communications, 31/Mar/2017