'Institute of Electrical and Electronics Engineers (IEEE)'
Abstract
Millimeter-wave (mm-wave) communication is the spectral frontier to meet the anticipated
significant volume of high data traffic processing in next-generation systems. The primary challenges in
mm-wave can be overcome by reducing complexity and power consumption by large antenna arrays for
massive multiple-input multiple-output (mMIMO) systems. However, the circuit power consumption is
expected to increase rapidly. The precoding in mm-wave mMIMO systems cannot be successfully achieved
at baseband using digital precoders, owing to the high cost and power consumption of signal mixers and
analog-to-digital converters. Nevertheless, hybrid analog–digital precoders are considered a cost-effective
solution. In this work, we introduce a novel method for optimizing energy efficiency (EE) in the upper-bound
multiuser (MU) - mMIMO system and the cost efficiency of quantized hybrid precoding (HP) design.
We propose effective alternating minimization algorithms based on the zero gradient method to establish
fully-connected structures (FCSs) and partially-connected structures (PCSs). In the alternating minimization
algorithms, low complexity is proposed by enforcing an orthogonal constraint on the digital precoders
to realize the joint optimization of computational complexity and communication power. Therefore, the
alternating minimization algorithm enhances HP by improving the performance of the FCS through
advanced phase extraction, which involves high complexity. Meanwhile, the alternating minimization
algorithm develops a PCS to achieve low complexity using HP. The simulation results demonstrate that the
proposed algorithm for MU - mMIMO systems improves EE. The power-saving ratio is also enhanced for
PCS and FCS by 48.3% and 17.12%, respectively
