Low-Complexity and Robust Quantized Hybrid Beamforming and Channel Estimation

Payami, Sohail; Masouro, Christos; Sellathurai, Mathini

doi:10.1109/glocom.2018.8647690

Cited by 7 publications

(7 citation statements)

References 17 publications

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“…It is noted that for L = 1, i.e. frequency-flat channel, our proposed RF beamformers becomes the same as narrow-and beamformer in [12], [31] and [21] turns into [5]. When L = 1, Fig.…”

Section: Simulation Resultsmentioning

confidence: 78%

“…When L = 1, Fig. 8 shows that using the RF beamformer of [5] results in a slightly higher spectral efficiency than [12], [31]; however, this is achieved at the cost of higher complexity.…”

Section: Simulation Resultsmentioning

confidence: 99%

“…PROOF OF PROPOSITION 4 Using (12), the frequency response of the effective channels in ( 9) and ( 10 Similarly, the first term in ( 48) is H e,1-tap,0 = W RF,0 H 0 (50)…”

Section: Appendix Dmentioning

confidence: 99%

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Low-Complexity Hybrid Beamforming for Massive MIMO Systems in Frequency-Selective Channels

2019

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Hybrid beamforming for frequency-selective channels is a challenging problem as the phase shifters provide the same phase shift to all of the subcarriers. The existing approaches solely rely on the channel's frequency response and the hybrid beamformers maximize the average spectral efficiency over the whole frequency band. Compared to state-of-the-art, we show that substantial sum-rate gains can be achieved, both for rich and sparse scattering channels, by jointly exploiting the frequency and time domain characteristics of the massive multiple-input multiple-output (MIMO) channels. In our proposed approach, the radio frequency (RF) beamformer coherently combines the received symbols in the time domain and, thus, it concentrates signal's power on a specific time sample. As a result, the RF beamformer flattens the frequency response of the "effective" transmission channel and reduces its root mean square delay spread. Then, a baseband combiner mitigates the residual interference in the frequency domain. We present the closed-form expressions of the proposed beamformer and its performance by leveraging the favorable propagation condition of massive MIMO channels and we prove that our proposed scheme can achieve the performance of fully-digital zero-forcing when number of employed phase shifter networks is twice the resolvable multipath components in the time domain.

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“…It is noted that for L = 1, i.e. frequency-flat channel, our proposed RF beamformers becomes the same as narrow-and beamformer in [12], [31] and [21] turns into [5]. When L = 1, Fig.…”

Section: Simulation Resultsmentioning

confidence: 78%

“…When L = 1, Fig. 8 shows that using the RF beamformer of [5] results in a slightly higher spectral efficiency than [12], [31]; however, this is achieved at the cost of higher complexity.…”

Section: Simulation Resultsmentioning

confidence: 99%

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Low-Complexity Hybrid Beamforming for Massive MIMO Systems in Frequency-Selective Channels

2019

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“…For sparse channels, e.g., the THz channel in this work, the DoD and DoA are demanding information for hybrid beamforming design. While for rich scattering channels, it has been studied in [34] that the DoD and DoA can be mapped to the correlation matrix which is a realistic requirement for the hybrid beamforming design to achieve high spectral efficiency.…”

Section: A Channel Model and The Practical Partial Csimentioning

confidence: 99%

Dynamic-subarray with Fixed Phase Shifters for Energy-efficient Terahertz Hybrid Beamforming under Partial CSI

Liu¹,

Chen²,

Yang³

et al. 2022

Preprint

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Terahertz (THz) communications are regarded as a pillar technology for the 6G systems, by offering multi-ten-GHz bandwidth. To overcome the huge propagation loss while reducing the hardware complexity, THz ultra-massive (UM) MIMO systems with hybrid beamforming are proposed to offer high array gain. Notably, the adjustable-phase-shifters considered in most existing hybrid beamforming studies are power-hungry and difficult to realize in the THz band. Moreover, due to the ultra-massive antennas, full channel-state-information (CSI) is challenging to obtain. To address these practical concerns, in this paper, an energy-efficient dynamic-subarray with fixed-phase-shifters (DS-FPS) architecture is proposed for THz hybrid beamforming. To compensate for the spectral efficiency loss caused by the fixed-phase of FPS, a switch network is inserted to enable dynamic connections. In addition, by considering the partial CSI, we propose a row-successive-decomposition (RSD) algorithm to design the hybrid beamforming matrices for DS-FPS. A row-by-row (RBR) algorithm is further proposed to reduce computational complexity. Extensive simulation results show that, the proposed DS-FPS architecture with the RSD and RBR algorithms achieves much higher energy efficiency than the existing architectures. Moreover, the DS-FPS architecture with partial CSI achieves 97% spectral efficiency of that with full CSI.

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“…As a result, they have been identified as one of the most promising approaches to implement systems that are based on 802.11 ay and 5G new radio. Hybrid beamformers can be divided into subconnected and fullyconnected structures, as shown in Figure 1 [18]- [20]. Theoretical analysis of different structures has shown that fullyconnected hybrid beamformers provide significantly more degrees of freedom to design algorithms and reach higher data rates.…”

Section: Introductionmentioning

confidence: 99%

Developing the First mmWave Fully-Connected Hybrid Beamformer With a Large Antenna Array

et al. 2020

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Millimeter wave (mmWave) systems with effective beamforming capability play a key role in fulfilling the high data-rate demands of current and future wireless technologies. Hybrid analog-todigital beamformers have been identified as a cost-effective and energy-efficient solution towards deploying such systems. Most of the existing hybrid beamforming architectures rely on a subconnected phase shifter network with a large number of antennas. Such approaches, however, cannot fully exploit the advantages of large arrays. On the other hand, the current fully-connected beamformers accommodate only a small number of antennas, which substantially limits their beamforming capabilities. In this paper, we present a mmWave hybrid beamformer testbed with a fully-connected network of phase shifters and adjustable attenuators and a large number of antenna elements. To our knowledge, this is the first platform that connects two RF inputs from the baseband to a 16× 8 antenna array, and it operates at 26 GHz with a 2 GHz bandwidth. It provides a wide scanning range of 60 • , and the flexibility to control both the phase and the amplitude of the signals between each of the RF chains and antennas. This beamforming platform can be used in both short and long-range communications with linear equivalent isotropically radiated power (EIRP) variation between 10 dBm and 60 dBm. In this paper, we present the design, calibration procedures and evaluations of such a complex system as well as discussions on the critical factors to consider for their practical implementation. INDEX TERMS Millimeter wave, Multiple-input multiple-output, fully-connected hybrid beamforming, phased array antenna, testbed.

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Low-Complexity and Robust Quantized Hybrid Beamforming and Channel Estimation

Cited by 7 publications

References 17 publications

Low-Complexity Hybrid Beamforming for Massive MIMO Systems in Frequency-Selective Channels

Low-Complexity Hybrid Beamforming for Massive MIMO Systems in Frequency-Selective Channels

Dynamic-subarray with Fixed Phase Shifters for Energy-efficient Terahertz Hybrid Beamforming under Partial CSI

Developing the First mmWave Fully-Connected Hybrid Beamformer With a Large Antenna Array

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