Beamforming Technologies for Ultra-Massive MIMO in Terahertz Communications

Ning, Boyu; Tian, Zhongbao; Mei, Weidong; Han, Chong; Li, Shaoqian; Yuan, Jinhong; Zhang, Rui

doi:10.1109/ojcoms.2023.3245669

Cited by 90 publications

(29 citation statements)

References 307 publications

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“…Furthermore, in the case of fully controllable beamformers with separate up-converter chains, it is required to have robust transmission systems with low PN and efficient PN to control the multiple-input multiple-output (MIMO) encoders accurately [2], [67]. Extremely high levels of PN may even impact the radiation pattern of the terahertz phased array, potentially even leading to the shaking of the beam partially similar to the deviations caused by the beam squint effect [68]- [70].…”

Section: Summary and Possible Extensionsmentioning

confidence: 99%

Modulations for Terahertz Band Communications: Joint Analysis of Phase Noise Impact and PAPR Effects

Parisi,

Badran,

Sen

et al. 2024

IEEE Open J. Commun. Soc.

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The choice of modulation techniques for next-generation communications in the sub-terahertz and terahertz bands remains largely unresolved. A variety of traditional and new schemes show promise, but the question remains open on the illustrative comparison process for realistic terahertz systems. While there are some preliminary studies in this area, we emphasize that the peculiarities of terahertz hardware necessitate a scheme that (i) is resistant to system-wide phase noise (PN) and (ii) has a low peak-to-average power ratio (PAPR). Therefore, in this article, we present a comprehensive methodology to carefully model and jointly study the impacts of PN and PAPR on the performance of candidate modulations for terahertz links. We first deliver a mathematical model for sub-terahertz/terahertz phase noise impairments at 130 GHz, 225 GHz, and 1.02 THz based on measurements from actual terahertz hardware. We then introduce the PAPR penalty -an approach for fair comparison of bit error rate (BER) and spectral efficiency (SE) of modulation schemes with different PAPRs. We finally combine these two effects to comprehensively study the characteristics of single and multi-carrier modulation schemes for terahertz communications. Our study reveals that analyzing PAPR and PN jointly is paramount: accounting for only one leads to major deviations in the numerical results and misleading conclusions on best modulation choice(s). The delivered framework and evaluation should facilitate further studies, leading to a well-motivated selection of the most suitable modulation scheme(s) for prospective sub-terahertz and terahertz radio systems.

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Section: Summary and Possible Extensionsmentioning

confidence: 99%

Modulations for Terahertz Band Communications: Joint Analysis of Phase Noise Impact and PAPR Effects

Parisi,

Badran,

Sen

et al. 2024

IEEE Open J. Commun. Soc.

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“…Massive multiple-input-multiple-output (MIMO) is a key technology for the fifth-generation wireless communications [1], [2]. Equipped with large antenna arrays, the base station (BS) can achieve high spectral efficiency dramatically by exploiting the spatial degree of freedom [3], [4]. To further enhance the spectral efficiency for the future sixth-generation wireless communications, extremely large-scale MIMO (XL-MIMO) that uses far more antennas than the existing massive MIMO is developed [5]- [7].…”

Section: Introductionmentioning

confidence: 99%

Beam Training and Tracking for Extremely Large-Scale MIMO Communications

Chen,

Qi,

Wang

et al. 2024

IEEE Trans. Wireless Commun.

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In this paper, beam training and beam tracking are investigated for extremely large-scale multiple-input-multipleoutput communication systems with partially-connected hybrid combining structures. Firstly, we propose a two-stage hybridfield beam training scheme for both the near field and the far field. In the first stage, each subarray independently uses multiple far-field channel steering vectors to approximate near-field ones for analog combining. To find the codeword best fitting for the channel, digital combiners in the second stage are designed to combine the outputs of the analog combiners from the first stage. Then, based on the principle of stationary phase and the timefrequency duality, the expressions of subarray signals after analog combining are analytically derived and a beam refinement based on phase shifts of subarrays (BRPSS) scheme with closedform solutions is proposed for high-resolution channel parameter estimation. Moreover, a low-complexity near-field beam tracking scheme is developed, where the kinematic model is adopted to characterize the channel variations and the extended Kalman filter is exploited for beam tracking. Simulation results verify the effectiveness of the proposed schemes.

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“…To deal with this problem, IRS's having a large number of reflecting elements can be deployed to better focus the radiated energy towards the intended user/location. On the other hand, dealing with large IRS panels in conjunction with massive multiple input multiple output (MIMO) systems makes channel estimation a challenging task [7], especially for passive IRS structures, where the bulk of signal processing and complexity associated with the estimation of the involved large-scale channels is transferred to the end nodes of the network [8]. Moreover, at high frequencies, the propagation channel is dominated by a few paths, which are more susceptible to blockages decreasing the overall coverage, throughput, and quality of service.…”

Section: Introductionmentioning

confidence: 99%

Semi-Blind Joint Channel and Symbol Estimation in IRS-Assisted Multiuser MIMO Networks

Araújo

Gomes

Almeida

et al. 2022

IEEE Wireless Commun. Lett.

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Intelligent reflecting surface (IRS) is a promising technology for the 6 th generation of wireless systems, realizing the smart radio environment concept. In this paper, we present a novel tensor-based receiver for IRS-assisted multiple-input multiple-output communications capable of jointly estimating the channels and the transmitted data streams in a semi-blind fashion. Assuming a fully passive IRS architecture and introducing a simple space-time coding scheme at the transmitter, the received signal model can be advantageously built using the PARATUCK tensor model, which can be seen as a hybrid of parallel factor analysis and Tucker models. Exploiting the algebraic structure of the PARATUCK tensor model, a semi-blind receiver is derived. The proposed receiver is based on a trilinear alternating least squares method that iteratively estimates the two involved -IRSbase station and user terminal-IRS -communication channels and the transmitted symbol matrix. We discuss identifiability conditions that ensure the joint semi-blind recovery of the involved channel and symbol matrices, and propose a joint design of the coding and IRS reflection matrices to optimize the receiver performance. For the proposed semi-blind receiver, the derivation of the expected Cramér-Rao lower bound is also provided. A numerical performance evaluation of the proposed receiver design corroborates its superior performance in terms of the normalized mean squared error of the estimated channels and the achieved symbol error rate.

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Beamforming Technologies for Ultra-Massive MIMO in Terahertz Communications

Cited by 90 publications

References 307 publications

Modulations for Terahertz Band Communications: Joint Analysis of Phase Noise Impact and PAPR Effects

Modulations for Terahertz Band Communications: Joint Analysis of Phase Noise Impact and PAPR Effects

Beam Training and Tracking for Extremely Large-Scale MIMO Communications

Semi-Blind Joint Channel and Symbol Estimation in IRS-Assisted Multiuser MIMO Networks

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