Article
Telecommunications
Hsiao-Feng Lu
Summary: This letter introduces new power allocation schemes for MIMO downlink communications, considering both sum-rate and fairness. By using a revised fairness measure, a comprehensive tradeoff between sum-rate and fairness is characterized, and a stochastic power allocation scheme is presented to achieve this tradeoff. An explicit rule for selecting operating sum-rate is proposed to put the optimal tradeoff into practical use. Simulation results demonstrate that the new scheme can achieve higher sum-rate and better fairness simultaneously.
IEEE COMMUNICATIONS LETTERS
(2021)
Article
Computer Science, Information Systems
Mingchuan Yang, Xinye Shao, Guanchang Xue, Botao Liu, Yanyong Su
Summary: This paper proposes an improved zero-forcing precoding algorithm to solve the co-frequency interference problem in high-throughput satellite communication systems. It also presents a low-complexity regularized zero-forcing dirty paper precoding algorithm.
Article
Engineering, Electrical & Electronic
Nibedita Nandan, Sudhan Majhi, Hsiao-Chun Wu
Summary: Physical layer security (PLS) is crucial in 5G wireless technology, particularly in the context of non-orthogonal multiple-access (NOMA) for spectrum sharing among multiple users. This study proposes a transmit-zero-forcing beamforming (ZFBF) technique with signal alignment to enhance PLS for MIMO-NOMA based cognitive radio networks, when perfect channel state information (CSI) is available at the base station (BS). Additionally, an eigen beamforming technique is introduced to improve PLS in the presence of imperfect CSI, with both techniques utilizing power allocation algorithms for further enhancement.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Niv Arad, Yair Noam
Summary: This paper proposes two contributions. The first is a new upper bound on the rate loss for an RRHs-cluster employing joint zero-forcing with incomplete CSI and single-user decoding at the MSs. The second contribution is a new CSI sharing scheme that reduces the overhead associated with acquiring global CSI for joint transmission.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Hongwen Yu, Hoang Duong Tuan, Eryk Dutkiewicz, H. Vincent Poor, Lajos Hanzo
Summary: This paper investigates a network architecture that combines a multi-antenna base station and a reconfigurable intelligent surface to provide information and power transmission to users. The authors propose a transmit-time switching approach to enable reliable connections for all users, optimizing energy links through conjugate beamforming and information links through programmable reflecting coefficients. They also introduce a path-following algorithm and a new beamforming method to enhance system performance.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
H. Yu, H. D. Tuan, E. Dutkiewicz, H. V. Poor, L. Hanzo
Summary: This paper focuses on hybrid beamforming for multi-user MIMO millimeter-wave communications, combining analog beamforming (ABF) and digital baseband beamforming (DBF). ABF reduces power consumption at the base station (BS) by using a limited number of radio frequency (RF) chains and finite-resolution phase-shifters, while DBF employs zero-forcing beamforming (ZFB) or regularized zero-forcing beamforming (RZFB) to mitigate multi-user interference. The joint design of ABF and DBF presents a computationally challenging optimization problem, and this paper develops efficient algorithms to solve it. Additionally, a new class of MU RZFB is proposed for achieving higher rates, and simulations confirm the effectiveness of the proposed algorithms and the advantages of the conceived RZFB.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Xingliang Lou, Wenchao Xia, Wanli Wen, Haitao Zhao, Xiaohui Li, Bin Wang
Summary: In this research, a beamforming neural network (BFNNet) is developed to maximize the weighted sum-rate in the multiple-input-single-output (MISO) system with dirty-paper coding (DPC) technique. The BFNNet utilizes deep learning, uplink-downlink duality, and explores the optimal solution structure to achieve near-optimal solutions and reduce computational complexity.
ELECTRONICS LETTERS
(2023)
Article
Computer Science, Information Systems
Jinho Kang, Wan Choi
Summary: In cooperative MIMO networks, adaptive feedback can reduce the overhead of CSI acquisition and sharing. By jointly optimizing regularization parameters and feedback bit allocation, the average sum rate can be effectively improved.
Article
Telecommunications
Mohamed Mostafa, Fatma Newagy, Ismail Hafez
Summary: In this paper, an energy efficient precoding scheme is proposed for massive MIMO systems by introducing a complex valued regularization parameter to improve energy efficiency, outperforming the conventional ZF precoder in terms of power consumption and achievable transmission rate. The proposed complex regularized zero forcing precoder is analytically evaluated, verified through simulations, and shown to be robust in massive MIMO systems.
WIRELESS PERSONAL COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Sung Ho Chae, Sang-Woon Jeon
Summary: This article investigates a new interference management scheme based on integer forcing (IF) receivers for the two-user multiple-input and multiple-output (MIMO) interference channel. The scheme utilizes a message splitting method and encodes all streams using the same lattice code to enable IF sum decoding. The number of common and private streams for each user is carefully determined to maximize the achievable rate. The proposed scheme outperforms previous benchmark schemes in a wide range of channel parameters due to the gain from IF sum decoding.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Shu Fang, Run Huang, Yue Xiao, Pengfei Zhu, Jun Xie, Shaofang Zhang, Jingyi Miao
Summary: A zero forcing assisted single layer beamforming technique for spatial modulation and space shift keying modulation MIMO systems, termed as SZF-SM/SZF-SSK, is proposed in this paper to achieve transmit beamforming and receive diversity gain. By mapping part of the bits to spatial domain, the proposed technique forms a ZF precoding assisted single layer data in both MISO and MIMO systems. The performance of the proposed technique is superior to traditional methods, especially under highly correlated MIMO channels.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Jiayi Zhang, Jing Zhang, Emil Bjornson, Bo Ai
Summary: This paper examines the impact of different signal processing schemes on efficiency in cell-free massive MIMO systems, finding that local regularized ZF provides the highest spectral efficiency. Protective weak PFZF is preferable when the number of pilot sequences or antennas per access point is large or small. Additionally, through fractional power control, performance for weak users can be improved, achieving uniformly good service for all users in a scalable manner.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2021)
Article
Telecommunications
Jingon Joung, Heejung Yu, Tony Q. S. Quek
Summary: This study focuses on addressing the challenges of interference in integrated sensing and communication (ISAC) systems and highlighting the advantages of multi-functional ISAC schemes. The authors propose a zero-forcing (ZF)-based beamforming and power allocation strategy and emphasize the importance of adaptive balance between sensing and communication capabilities. The research demonstrates that relying solely on single function-aware schemes is insufficient and that integrated sensing and communication functionalities are crucial for efficient ISAC systems.
VEHICULAR COMMUNICATIONS
(2023)
Article
Computer Science, Theory & Methods
Kan Wang, Xuan Liu, Hongfang Zhou, Dapeng Lan, Zhen Gao, Amir Taherkordi, Yujie Ye, Yuan Gao
Summary: This paper investigates the online service function chaining (SFC) deployment in the edge of 6G wireless systems using artificial intelligence and reinforcement learning. It proposes a coordinated multiple points (CoMP)-based zero-forcing beamforming method to cancel interference between SFCs. It also introduces a natural gradient-based actor-critic framework to model edge network dynamics and train neural networks to the global optimum.
FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF ESCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Liutong Du, Lihua Li, Hien Quoc Ngo, Trang C. Mai, Michail Matthaiou
Summary: The proposed joint maximum-ratio and zero-forcing (JMRZF) precoding scheme in cell-free massive MIMO systems offers a balance between spectral efficiency and front-haul signaling overhead. AP subset selection based on large-scale fading coefficients is introduced, along with max-min power control to optimize system performance. This scheme outperforms local precoding methods and significantly improves spectral efficiency compared to uniform power control.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2021)
Review
Pharmacology & Pharmacy
Muhammad Saqib Sohail, Syed Faraz Ahmed, Ahmed Abdul Quadeer, Matthew R. McKay
Summary: Growing evidence indicates the critical role T cells may play in combating SARS-CoV-2, highlighting the importance of COVID-19 vaccines that can elicit a robust T cell response. In silico methods have been used for the prediction of SARS-CoV-2 T cell epitopes, revealing potential future research directions.
ADVANCED DRUG DELIVERY REVIEWS
(2021)
Article
Biotechnology & Applied Microbiology
Muhammad Saqib Sohail, Raymond H. Y. Louie, Matthew R. McKay, John P. Barton
Summary: Genetic linkage plays a significant role in determining the fate of new mutations and their effects on fitness in evolving populations. Resolving genetic linkage is crucial for accurately quantifying selection and understanding the impact of mutations on evolutionary histories.
NATURE BIOTECHNOLOGY
(2021)
Article
Telecommunications
Neel Kanth Kundu, Soumya P. Dash, Matthew R. McKay, Ranjan K. Mallik
Summary: A MIMO quantum key distribution scheme for terahertz frequency applications has been proposed, showing improved performance with multiple antennas and positive key rates achievable in the 10 - 30 THz frequency range.
IEEE COMMUNICATIONS LETTERS
(2021)
Article
Virology
Syed Faraz Ahmed, Ahmed Abdul Quadeer, Matthew R. McKay
Summary: The study assessed the impact of Omicron mutations on known T cell epitopes and found that T cell responses to this new variant remain robust.
Article
Multidisciplinary Sciences
Hang Zhang, Ahmed A. Quadeer, Matthew R. McKay
Summary: This study provides a comparative analysis of evolutionary models of HCV subtype 1b, revealing a higher chronic infection rate due to lower fitness constraints and easier escape from antibody responses compared to subtype 1a. The study also identifies antibodies that are escape-resistant against both subtypes, offering directions for developing HCV vaccines with cross-subtype protection.
Article
Engineering, Electrical & Electronic
Neel Kanth Kundu, Soumya P. Dash, Matthew R. Mckay, Ranjan K. Mallik
Summary: We study the secret key rate (SKR) of a multiple-input multiple-output (MIMO) continuous variable quantum key distribution (CVQKD) system operating at terahertz (THz) frequencies, accounting for the effects of channel estimation. We propose a practical channel estimation scheme for the THz MIMO CVQKD system and analyze the impact of channel estimation error and overhead. Our simulation results show that the SKR may significantly degrade at large transmission distances.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2022)
Article
Computer Science, Information Systems
Neel Kanth Kundu, Zan Li, Junhui Rao, Shanpu Shen, Matthew R. McKay, Ross Murch
Summary: This letter presents an analytical study of RIS element grouping in communication systems. The authors derive a tight upper bound for the achievable rate and maximize it with respect to the group size. Their analysis reveals that more coarse-grained grouping is important in low channel coherence time or high transmit power scenarios, and optimal grouping can yield significant performance improvements compared to simple 'On-Off' RIS element switching schemes.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2022)
Article
Immunology
Syed Faraz Ahmed, Muhammad Saqib Sohail, Ahmed Abdul Quadeer, Matthew R. McKay
Summary: Memory CD8(+) T cell responses induced by SARS-CoV-2 infection or COVID-19 vaccination play a crucial role in protecting against severe disease and are resilient against variants of concern. However, future genetic mutations in the virus may weaken T cell immunity and result in widespread T cell escape. To facilitate targeted experimental studies, researchers have compiled a list of potential SARS-CoV-2 T cell escape mutants that lie within commonly targeted CD8(+) T cell epitopes.
Article
Biochemistry & Molecular Biology
Muhammad Saqib Sohail, Raymond H. Y. Louie, Zhenchen Hong, John P. Barton, Matthew R. McKay
Summary: This article introduces a method for inferring epistasis and the fitness effects of individual mutations from observed evolutionary histories. Simulations show that this method can accurately infer pairwise epistatic interactions when there is sufficient genetic diversity in the data.
MOLECULAR BIOLOGY AND EVOLUTION
(2022)
Article
Virology
Syed Faraz Ahmed, Muhammad Saqib Sohail, Ahmed Abdul Quadeer, Matthew R. McKay
Summary: In May 2022, a novel cluster of monkeypox virus infections in humans was detected, causing global concern. Vaccines based on the vaccinia virus have been highly effective against monkeypox viruses in the past, but the current outbreak involves genetic variations that may impact vaccine-induced immune recognition. However, research suggests that VACV-based vaccines, including MVA-BN and ACAM2000, are still highly cross-reactive against the newly observed monkeypox viruses.
Article
Computer Science, Information Systems
Zan Li, Neel Kanth Kundu, Junhui Rao, Shanpu Shen, Matthew R. McKay, Ross Murch
Summary: We investigate the performance of a reconfigurable intelligent surface (RIS) assisted single-input single-output (SISO) communication system with narrowly spaced RIS elements and spatially correlated channels. Grouping adjacent RIS elements reduces channel estimation overhead. Analytically derived statistical properties of optimal received SNR are used to characterize system coverage probability. An analytical upper bound for average achievable rate is also derived. The results show that spatially correlated RIS elements achieve higher average achievable rate compared to uncorrelated configurations.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2023)
Article
Multidisciplinary Sciences
Haogao Gu, Ahmed Abdul Quadeer, Pavithra Krishnan, Daisy Y. M. Ng, Lydia D. J. Chang, Gigi Y. Z. Liu, Samuel M. S. Cheng, Tommy T. Y. Lam, Malik Peiris, Matthew R. McKay, Leo L. M. Poon
Summary: Limited data is available on the genetic diversity of SARS-CoV-2 within hosts and its relationship with vaccination. The authors found that variant of Concern (VOC) samples have more sequence variations than non-VOC samples, and breakthrough infections in vaccinated individuals do not increase non-silent mutations. The study highlights the importance of understanding within-host diversity and the impact of vaccination on viral evolution.
NATURE COMMUNICATIONS
(2023)
Article
Statistics & Probability
David Morales-Jimenez, Iain M. Johnstone, Matthew R. McKay, Jeha Yang
Summary: For high-dimensional data, using random matrix theory can help derive asymptotic results for the spectral properties of sample correlation matrices.
While the first-order spectral properties of sample correlation matrices match those of sample covariance matrices, their asymptotic distributions can differ significantly.
The fluctuations of both sample eigenvalues and eigenvectors based on correlations are often much smaller than those of their sample covariance counterparts.
Article
Engineering, Electrical & Electronic
Nicolas Auguin, David Morales-Jimenez, Matthew McKay
Summary: In this study, a robust version of linear discriminant analysis (LDA) classifiers is proposed to address potential spurious or mislabeled observations in training data. The robust LDA relies on a robust estimate of the covariance matrix of the training data. Results show that the use of robust estimators does not degrade the performance of LDA, especially when data are corrupted by outliers or random noise.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2021)
Article
Engineering, Electrical & Electronic
Neel Kanth Kundu, Matthew R. McKay
Summary: This study focuses on multi-antenna wireless systems aided by reconfigurable intelligent surfaces (RIS) to improve coverage and energy efficiency by controlling the propagation environment intelligently. Accurate channel estimation is crucial for achieving the anticipated gains of RIS. The authors propose approaches to approximate the optimal MMSE channel estimator, including a linear estimator LMMSE and data-driven nonlinear solutions based on deep learning.
IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY
(2021)