Hybrid MIMO Architectures for Millimeter Wave Communications: Phase Shifters or Switches?

Microwave And Millimeter-Wave Ferrite Phase Shifters

Low-loss Millimeter-wave Phase Shifters Based on Mechanical Reconfiguration

We propose different concepts of mechanically reconfigurable true-time-delay phase shifters using micro-actuators at millimeter-waves (MMW). The mechanical reconfiguration allows to achieve phase shift reconfiguration with very low losses. One of the proposed concepts has been fully implemented and tested, demonstrating state-of-the-art performance in terms of phase-shift/loss ratio.

Rate Loss of Hybrid Beamforming with Imperfect Phase Shifters in Millimeter Wave Systems

In millimeter massive MIMO systems, hybrid beamforming algorithms with fewer RF chain are widely applied as they can save power and cut down on hardware costs. Hybrid beamforming can be divided into two stages: analog beamforming in the RF domain usually implemented with phase shifters and digital beamforming in the baseband domain. Phase shifters have rms phase error and rms gain error which a...

GMD-Based Hybrid Precoding For Millimeter-Wave Massive MIMO Systems

Hybrid precoding can significantly reduce the number of required radio frequency (RF) chains and relieve the huge energy consumption in mmWave massive MIMO systems, thus attracting much interests from academic and industry. However, most existing hybrid precoding schemes are based on singular value decomposition (SVD). Due to the very different subchannel signal-to-noise ratios (SNRs) after SVD...

Multiuser Millimeter Wave MIMO Channel Estimation with Hybrid Beamforming

This paper focuses on multiuser MIMO channel estimation and data transmission at millimeter wave (mmWave) frequencies. The proposed approach relies on the time-divisionduplex (TDD) protocol and is based on two distinct phases. First of all, the Base Station (BS) sends a suitable probing signal so that all the Mobile Stations (MSs), using a subspace tracking algorithm, can estimate the dominant ...