Hybrid Beamforming Analysis Based on MIMO Channel Measurements at 28 GHz

Abstract

<div>Hybrid beamforming systems represent an efficient</div><div>architectural solution to realize massive multiple-input multiple-output (MIMO) communication systems in the centimeter wave (cmW) and millimeter wave (mmW) region. These hybrid beamforming systems separate the beamforming process into a digital and analog beamforming network. The analog beamforming networks can be realized by different architectural solutions, which demand dedicated algorithms to determine the complex weighting factors in the digital and analog domain. To date, novel hybrid beamforming architectures and algorithms are solely compared in numerical simulations based on statistical channel models. These abstract channel models simplify the complicated electromagnetic propagation process, thereby not exactly reconstructing the wireless channel. Within this work, we present a measurement-based evaluation of hybrid beamforming algorithms and compare them with numerical results gained from a statistical path-based MIMO channel model. The results show that by adjustment of the channel model parameter the simulation achieves a good match with the measured maximum achievable spectral efficiencies.</div>

Sparse Array Channel Estimation for Subarray-Based Hybrid Beamforming Systems

“…The beamforming matrix W is then constructed as described in a previous study [23], by steering each subarray towards one of the N dig directions with the strongest received power. The pseudo-code for the SABA algorithm is shown in Algorithm 2.…”