TY - JOUR
T1 - Limited Feedback Hybrid Beamforming for Multi-Mode Transmission in Wideband Millimeter Wave Channel
AU - Kwon, Girim
AU - Park, Hyuncheol
N1 - Publisher Copyright:
© 2002-2012 IEEE.
PY - 2020/6
Y1 - 2020/6
N2 - A major bottleneck in millimeter wave hybrid beamforming (BF) system is the limited number of radio frequency (RF) chains at the base station (BS). For example, when the number of users is large, the joint user scheduling and BF design is needed under the hardware constraint. Fortunately, if multiple RF chains are available at both BS and users, the system performance can significantly be improved by multi-mode transmission, which assigns different numbers of streams to the users. However, the optimal multi-mode scheme may require high feedback-feedforward overhead and complexity. Furthermore, since the mmWave BF system operates in a large bandwidth, the wideband channel should be considered. To tackle this problem, we propose the single-carrier (SC) hybrid BF scheme based on the limited feedback information. We maximize the weighted sum rate by adopting the multi-mode transmission based on the RF beam alignment. The proposed SC hybrid BF scheme outperforms the existing orthogonal frequency division multiplexing (OFDM)-based hybrid BF schemes. From the analysis, we find that full spatial multiplexing gain is guaranteed if we scale the number of RF chains at the BS as smaller than the square root of the number of antennas in a large number of users regime.
AB - A major bottleneck in millimeter wave hybrid beamforming (BF) system is the limited number of radio frequency (RF) chains at the base station (BS). For example, when the number of users is large, the joint user scheduling and BF design is needed under the hardware constraint. Fortunately, if multiple RF chains are available at both BS and users, the system performance can significantly be improved by multi-mode transmission, which assigns different numbers of streams to the users. However, the optimal multi-mode scheme may require high feedback-feedforward overhead and complexity. Furthermore, since the mmWave BF system operates in a large bandwidth, the wideband channel should be considered. To tackle this problem, we propose the single-carrier (SC) hybrid BF scheme based on the limited feedback information. We maximize the weighted sum rate by adopting the multi-mode transmission based on the RF beam alignment. The proposed SC hybrid BF scheme outperforms the existing orthogonal frequency division multiplexing (OFDM)-based hybrid BF schemes. From the analysis, we find that full spatial multiplexing gain is guaranteed if we scale the number of RF chains at the BS as smaller than the square root of the number of antennas in a large number of users regime.
KW - hybrid beamforming
KW - limited feedback
KW - single-carrier transmission
KW - user scheduling
KW - Wideband millimeter wave channel
UR - http://www.scopus.com/inward/record.url?scp=85087198206&partnerID=8YFLogxK
U2 - 10.1109/TWC.2020.2979184
DO - 10.1109/TWC.2020.2979184
M3 - Article
AN - SCOPUS:85087198206
SN - 1536-1276
VL - 19
SP - 4008
EP - 4022
JO - IEEE Transactions on Wireless Communications
JF - IEEE Transactions on Wireless Communications
IS - 6
M1 - 9036100
ER -