%0 Journal Article %J IEEE Trans. Wireless Communications %D 2022 %T Hybrid Beamforming Designs for Frequency-Selective mmWave MIMO Systems with Per-RF chain or Per-antenna Power Constraints %A R. López-Valcarce %A Nuria González-Prelcic %K mmWave %K rodin %X
Configuring precoders and combiners is a major
challenge to deploy practical multiple-input multiple-output
(MIMO) millimeter wave (mmWave) communication systems
with large antenna arrays. Most prior work addresses the problem
focusing on a total transmit power constraint. In practical
transmitters, however, power amplifiers must operate within their
linear range, so that a power constraint applies to each one
of the input signals to these devices. Therefore, precoder and
combiner designs should incorporate per-antenna or per-radio
frequency (RF) chain transmit power constraints. We focus on
such problem for frequency-selective channels with multicarrier
modulation, and assuming hybrid analog/digital architectures
based on fully connected analog blocks implemented with finite resolution
phase shifters. We first derive an all-digital solution
which aims to maximize spectral efficiency. Then, we develop
hybrid precoders and combiners by approximately matching
the corresponding all-digital matrices while still enforcing the
power constraints. Numerical results show that the proposed
all-digital design performs close to the upper bound given
by the standard waterfilling-based solution with a total power
constraint. Additionally, the hybrid designs exhibit a moderate
loss even when low-resolution phase shifters are considered.
%B IEEE Trans. Wireless Communications %V 21 %P 5770-5784 %8 08/2022 %G eng %N 8 %& 5770 %R 10.1109/TWC.2022.3142959