Hybrid Digital and Analog Beamforming Design for Large-Scale Antenna Arrays

By Foad Sohrabi, Wei Yu. IEEE Journal on Selected Topics in Signal Processing, 2016

1,399 citations recorded by the source corpus.

The potential of using of millimeter wave (mmWave) frequency for future wireless cellular communication systems has motivated the study of large-scale antenna arrays for achieving highly directional beamforming. However, the conventional fully digital beamforming methods which require one radio frequency (RF) chain per antenna element is not viable for large-scale antenna arrays due to the high cost and high power consumption of RF chain components in high frequencies. To address the challenge of this hardware limitation, this paper considers a hybrid beamforming architecture in which the overall beamformer consists of a low-dimensional digital beamformer followed by an RF beamformer implemented using analog phase shifters. Our aim is to show that such an architecture can approach the performance of a fully digital scheme with much fewer number of RF chains. Specifically, this paper establishes that if the number of RF chains is twice the total number of data streams, the hybrid beamforming structure can realize any fully digital beamformer exactly, regardless of the number of antenna elements. For cases with fewer number of RF chains, this paper further considers the hybrid beamforming design problem for both the transmission scenario of a point-to-point multiple-input multiple-output (MIMO) system and a downlink multi-user multiple-input single-output (MU-MISO) system. For each scenario, we propose a heuristic hybrid beamforming design that achieves a performance close to the performance of the fully digital beamforming baseline. Finally, the proposed algorithms are modified for the more practical setting in which only finite resolution phase shifters are available. Numerical simulations show that the proposed schemes are effective even when phase shifters with very low resolution are used.

Subfields: Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/c82a329c5916e23d0f2d805a5d3b29f1ab9dd7f1

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Citations in the corpus

5G: A Tutorial Overview of Standards, Trials, Challenges, Deployment, and Practice (2017, methodology): “Despite the constraints on HBF, it has been shown that fully digital performance can be obtained if N RF ≥ 2 N s [23], [122].”
Spatial- and Frequency-Wideband Effects in Millimeter-Wave Massive MIMO Systems (2017, methodology): “Most of the existing works on massive MIMO are based on the channel model directly extended from the conventional MIMO channel model [5]–[22].”
Weighted Sum-Rate Maximization for Reconfigurable Intelligent Surface Aided Wireless Networks (2019, methodology): “The formulated problem looks mathematically similar to the WSR maximization problem in the hybrid digital/analog precoding [27]–[29] in massive MIMO systems.”
Beam Focusing for Near-Field Multi-User MIMO Communications (2021, methodology): “This observation is consistent with existing results in far-field communications, where it is established that any fully-digital beamforming solution can be realized by a hybrid beamforing solution when the number of RF chains is at least twice the number of users (data streams) [18].”
Beamforming Optimization for Intelligent Reflecting Surface with Discrete Phase Shifts (2018, background): “Although massive multiple-input multiple-output (MIMO) technology has significantly improved the spectrum and energy efficiency of wireless communication systems, the required high complexity and high hardware cost is still the main hindrance to its implementation in practice, especially at higher f”
Evolution of NOMA Toward Next Generation Multiple Access (NGMA) for 6G (2021, background): “, the unit-modulus constraints in hybrid/analog/constant-envelope precoding problems [185]–[187] and reflection coefficient design in RISaided networks).”
Movable-Antenna Enhanced Multiuser Communication via Antenna Position Optimization (2023, methodology): “To evaluate the performance gain provided by MAs, it is essential to characterize the channel variation between the antenna array of the BS and each user’s antenna moving in a given 3D spatial region.”
Hybrid Beamforming for Reconfigurable Intelligent Surface based Multi-User Communications: Achievable Rates With Limited Discrete Phase Shifts (2019, methodology): “Since the RIS elements do not have any digital processing capability, we consider hybrid beamforming (HBF) [19] consisting of digital beamforming at the BS and RIS configuration based analog beamforming.”
Intelligent Reflecting Surface Enhanced Wireless Network via Joint Active and Passive Beamforming (2018, background): “Although beamforming optimization under unit-modulus constraints has been studied in the research on constant-envelope precoding [11], [12] as well as hybrid digital/analog processing [13], [14], such designs are mainly restricted to either the transmitter or the receiver side, which are not applica”
Hybrid Analog and Digital Beamforming for mmWave OFDM Large-Scale Antenna Arrays (2017, methodology): “The common message from different algorithms presented in [11]–[15] is that hybrid beamforming with the number of RF chains in the order of number of data streams can approach the performance of fully-digital beamforming baselines in ﬂat-fading channels.”
Beamforming Optimization for Wireless Network Aided by Intelligent Reflecting Surface With Discrete Phase Shifts (2019, background): “2958916 and high hardware cost are still the main hindrances to its implementation in practice [2]–[5].”
Modeling and Analyzing Millimeter Wave Cellular Systems (2016, background): “The solutions in [103], [113], [115], [116], and [130]–[133] showed that hybrid precoding can generally achieve very good spectral efficiencies compared to the fully-digital SVD solution in mmWave systems, specially when the number of RF chains is close to the number of dominant channel paths.”
Near-Field Communications: A Tutorial Review (2023, methodology): “Additionally, as pointed out in [50], for the fullyconnected hybrid beamforming architecture, 2Ns RF chains are sufficient to achieve the same performance as a fullydigital beamformer, which implies that deploying more than 2Ns RF chains will only result in more power consumption without enhancing c”
A Survey on Hybrid Beamforming Techniques in 5G: Architecture and System Model Perspectives (2018, methodology): “For example, it has been proved that hybrid beamforming can achieve close to the optimal digital beamforming performance with reduced complexity [81].”