Article
Computer Science, Information Systems
Qi Lin, Hong Shen, Chunming Zhao
Summary: This letter proposes a deep learning based linear precoder design to improve the performance of uplink multiuser multiple-input multiple-output (MU-MIMO) systems with one-bit analog-to-digital converters (ADCs). By optimizing the precoder at each user equipment (UE) using a Bussgang decomposition based linear minimum mean squared error (MMSE) receiver at the base station (BS), the system MSE can be further minimized. To efficiently address this problem, a deep neural network based approach is proposed by unfolding the developed projected gradient descent (PGD) algorithm and treating the step size in each PGD iteration as trainable network parameters. Simulation results show that the proposed network design outperforms the conventional PGD algorithm under both perfect and estimated channel state information (CSI) and achieves improvement with reduced online complexity.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Liangyuan Xu, Cheng Qian, Feifei Gao, Wei Zhang, Shaodan Ma
Summary: The study focuses on the application of one-bit ADC/DAC in mmWave MIMO systems for UL/DL channel estimation and precoding. Proposed algorithms show advantages over existing techniques in terms of accuracy and computational complexity.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2021)
Article
Telecommunications
Ruizhe Wang, Hong Ren, Cunhua Pan, Jun Fang, Mianxiong Dong, Octavia A. Dobre
Summary: This letter investigates the cascaded channel estimation problem for a mmWave massive MIMO system aided by a reconfigurable intelligent surface (RIS) with the base station (BS) equipped with few-bit ADCs. By exploiting the low-rank property of the cascaded channel, the estimation problem is formulated as a low-rank matrix completion problem. The Bayesian optimal inference framework is introduced to tackle information loss caused by quantization. The efficient bilinear generalized approximate message passing (BiG-AMP) algorithm is used to implement the estimator and achieve matrix completion. Extensive simulation results verify the accurate estimation of the cascaded channel for the RIS-aided mmWave massive MIMO system with low-resolution ADCs.
IEEE COMMUNICATIONS LETTERS
(2023)
Article
Telecommunications
Ruizhe Wang, Hong Ren, Cunhua Pan, Jun Fang, Mianxiong Dong, Octavia A. Dobre
Summary: This study investigates the cascaded channel estimation for a mmWave massive MIMO system aided by a reconfigurable intelligent surface (RIS) with the base station equipped with few-bit analog-to-digital converters (ADCs). By introducing the Bayesian optimal inference framework and using the efficient bilinear generalized approximate message passing (BiG-AMP) algorithm, the proposed method accurately estimates the cascaded channel for the RIS-aided mmWave massive MIMO system with low-resolution ADCs.
IEEE COMMUNICATIONS LETTERS
(2023)
Article
Computer Science, Information Systems
Meng Zhou, Yao Zhang, Xu Qiao, Mangang Xie, Longxiang Yang, Hongbo Zhu
Summary: This article explores the effects of multi-antenna users and low-resolution DACs on cell-free massive MIMO systems, deriving closed-form expressions for sum spectral efficiency and energy efficiency. The study shows that multicast is better than unicast when sum-SE is small, and replacing full-resolution DAC with a 5-bit DAC can achieve the same performance. Additionally, extra antennas at user end can enhance system performance, and 2-bit DAC quantization achieves maximum sum EE. Simulation results are provided to verify the derived results.
IEEE SYSTEMS JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
Italo Atzeni, Antti Tolli
Summary: This paper presents an analytical framework for channel estimation and data detection in massive multiple-input multiple-output uplink systems. Closed-form expressions for channel estimation mean squared error and estimated symbol statistics in data detection are derived. The analysis depends on key system parameters and provides a precise characterization of performance with 1-bit ADCs.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Minglong Deng, Ziyang Cheng, Zishu He
Summary: This paper investigates the design of receive filters for MIMO radar with one-bit ADCs. The probabilities of detection and false-alarm are derived for MIMO radar with one-bit ADCs, and the receive filter is obtained by maximizing the probability of detection subject to a fixed false-alarm. The performance difference between one-bit and infinite-bit quantizations is evaluated from the SNR point of view. Additionally, methods are proposed to estimate the noise parameters and overcome the uncertainty of the target scattering coefficient.
DIGITAL SIGNAL PROCESSING
(2022)
Article
Chemistry, Multidisciplinary
Roger Kwao Ahiadormey, Kwonhue Choi
Summary: This paper proposes rate-splitting multiple access for low-resolution ADC/DAC in multiuser massive MIMO systems, investigating the spectral efficiency and energy efficiency under imperfect CSI. The results show that as the resolution of ADC/DAC increases, the RS scheme achieves higher spectral efficiency in high SNR scenarios.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Electrical & Electronic
Don-Roberts Emenonye, Carl Dietrich, R. Michael Buehrer
Summary: In this paper, a differential modulation and detection scheme for a multi-antenna base station with low-resolution ADCs is presented. The maximum likelihood detector for differentially encoded phase information symbol in the low-resolution ADC regime is derived, along with a reduced complexity receiver. A maximum likelihood expression for detecting differential amplitude phase shift keying symbols with low-resolution ADCs is also provided. The paper introduces two detectors capable of detecting the amplitude information using the Bussgang Theorem and the Central Limit Theorem (CLT). The performance and complexity of the proposed detectors are evaluated through simulations.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Chemistry, Analytical
Tae-Kyoung Kim
Summary: This study proposes an improvement in likelihood probability for MIMO systems using one-bit ADCs. The proposed method estimates the true likelihood probability by combining the initial likelihood probability with the detected symbols. An optimization problem is formulated to minimize the mean-squared error between the true and combined likelihood probabilities, and a solution is derived using the least-squares method. Simulation results show that the proposed method achieves a signal-to-noise gain of approximately 0.3 dB and a frame error rate of 10(-1), indicating improved performance due to enhanced reliability of the likelihood probability.
Article
Engineering, Electrical & Electronic
Youzhi Xiong, Sanshan Sun, Li Liu, Zhongpei Zhang, Ning Wei
Summary: This paper focuses on a cell-free massive MIMO network with variable-resolution ADCs. The authors propose a quantization-aware channel estimator based on LMMSE theory, and investigate bit allocation problems for intra-AP and inter-AP scenarios to maximize channel estimation quality. The theoretical expressions of achievable uplink SE for MRC and MMSE combining are derived, and bit allocation problems for both single-user and multi-user scenarios are also explored. Simulation results confirm the correctness of the theoretical analyses and provide insights into the proposed bit allocation techniques.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2023)
Article
Computer Science, Information Systems
Yao Zhang, Longxiang Yang, Hongbo Zhu
Summary: This article studies the achievable rates of uplink and downlink for cell-free massive MIMO systems over Rician fading channels with low-resolution ADCs. Closed-form rate expressions and power optimization algorithms are derived and verified by simulation experiments.
IEEE SYSTEMS JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
In-Soo Kim, Junil Choi
Summary: This article proposes a channel estimator for wideband millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems with hybrid architectures and low-resolution analog-to-digital converters (ADCs). The discrete time channel modeling the spatial wideband effect is developed, considering the propagation delay across the antenna array. The training signal design addressing interferences is investigated, and a new channel estimator based on the maximum a posteriori (MAP) criterion is proposed for estimating channel parameters over the continuum.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Bule Sun, Yiqing Zhou, Jinhong Yuan, Ya-Feng Liu, Lu Wang, Ling Liu
Summary: This paper investigates high order PSK signal transmission in 1-bit ADC massive MIMO systems, theoretically proving that arbitrary modulation order PSK signals can be recovered with a large number of antennas at the base station. The impact of pilot based channel estimation on high order PSK signal recovery is analyzed, leading to an optimized pilot sequence proposal for improved detection performance. Simulation results confirm the effectiveness of the proposed optimized pilot sequence in enhancing detection performance in both single-MS and multi-MS scenarios for 1-bit ADC massive MIMO systems.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Weimin Du, Zujun Liu
Summary: Quantization allows for cheap and power-efficient implementation of massive MIMO using radio frequency front-ends, but it also introduces severe amplitude distortion. The spatial sigma - delta structure is a key method for recovering amplitude information from one-bit quantized signals. However, existing schemes like zero forcing or maximum ratio combination struggle to achieve the upper bound of spatial quantization noise reduction (DQNR), limiting distortion suppression. To address this issue, we propose random and accurate beam shaping schemes that exploit the large-scale antenna array more efficiently to recover amplitude information.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Entomology
Mark M. Stevens, Gregory J. Daglish, Beverley A. Orchard, Glen N. Warren, Jianhua Mo, Jessica L. Hoskins
Summary: In order to understand the field ecology of stored grain beetles in southern Australia, the flight activity of Rhyzopertha dominica and Tribolium castaneum was monitored over a 2-year period. The results showed that R. dominica was more likely to be caught in areas of remnant vegetation, while T. castaneum was predominantly caught near storages. A heatwave during summer resulted in a decline in captures for both species. Mark/release/recapture trials demonstrated the short half-life of R. dominica pheromone lures and the impact of weather on lure attractivity.
JOURNAL OF STORED PRODUCTS RESEARCH
(2023)
Article
Engineering, Electrical & Electronic
Mohamed Akrout, Volodymyr Shyianov, Faouzi Bellili, Amine Mezghani, Robert W. Heath
Summary: This paper presents a novel information-theoretic approach to study the impact of mutual coupling (MC) between transmit and receive antennas on the performance of single-input-single-output (SISO) near-field communications (NFC). By incorporating finite antenna size constraint using Chu's theory and assuming canonical-minimum scattering (CMS), the paper derives the MC between two fixed-size radiating volumes. The expressions for self and mutual impedances are obtained utilizing the reciprocity theorem.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Yi Zhang, Robert W. Heath Jr
Summary: This article discusses the challenges of establishing and maintaining millimeter-wave links and highlights the potential of using the multi-armed bandit framework for optimal configuration.
IEEE VEHICULAR TECHNOLOGY MAGAZINE
(2023)
Article
Dermatology
Ziye Chen, Qiong Cheng, Lingyun Wang, Yunfeng Mo, Ke Li, Jianhua Mo
Summary: Artificial dermal scaffold (ADS) has been widely used for treating skin wound in clinics, but there are no effective, real-time, and noninvasive techniques for monitoring ADS. In this study, we propose to use optical coherence tomography (OCT) for in vivo monitoring of ADS through three-dimensional imaging and show that OCT has the potential to monitor ADS in real time.
LASERS IN SURGERY AND MEDICINE
(2023)
Article
Biochemical Research Methods
Xiaojun Yu, Chenkun Ge, Mingshuai Li, Miao Yuan, Linbo Liu, Jianhua Mo, Perry Ping Shum, Jinna Chen
Summary: This paper proposes a novel self-supervised deep learning scheme, called B2Unet, for speckle reduction in optical coherence tomography (OCT). Experimental results comparing B2Unet with existing methods convincingly demonstrate its effectiveness in suppressing speckles while preserving important tissue micro-structures.
BIOMEDICAL OPTICS EXPRESS
(2023)
Article
Computer Science, Information Systems
Nitish Deshpande, Miguel R. R. Castellanos, Saeed R. R. Khosravirad, Jinfeng Du, Harish Viswanathan, Robert W. W. Heath
Summary: The conventional wireless system design assumption of narrowband and far-field does not match with the optimal beamforming required for wideband and near-field systems. This discrepancy is more visible when dealing with larger apertures and bandwidths. In order to understand the behavior of near-field and wideband systems, we derive the beamforming gain expression achieved by a frequency-flat phased array designed for plane-wave propagation. Additionally, we propose a frequency-selective distance metric to determine the far-field to near-field boundary for a wideband system. The analysis provides an upper bound on the product of the array aperture and the system bandwidth and shows how the gain threshold affects the maximum usable bandwidth for the n260 and n261 5G NR bands.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2023)
Article
Radiology, Nuclear Medicine & Medical Imaging
Xiaojun Yu, Chenkun Ge, Mingshuai Li, Muhammad Zulkifal Aziz, Jianhua Mo, Zeming Fan
Summary: A multiscale denoising generative adversarial network (MDGAN) is proposed for speckle reduction in OCT images. Experimental results show that MDGAN can effectively improve image quality and enhance diagnosis accuracy.
JOURNAL OF MEDICAL IMAGING
(2023)
Article
Engineering, Electrical & Electronic
Kai Wu, J. Andrew Zhang, Xiaojing Huang, Robert W. Heath, Y. Jay Guo
Summary: This article introduces the energy-efficient and easy-to-design multi-beam antenna arrays (MBAAs) for joint communications and sensing (JCAS), which can simultaneously steer multiple beams with negligible power consumption. It also discusses the challenges and opportunities to foster the development of green JCAS systems.
IEEE COMMUNICATIONS MAGAZINE
(2023)
Article
Engineering, Electrical & Electronic
Mohamed Akrout, Volodymyr Shyianov, Faouzi Bellili, Amine Mezghani, Robert W. W. Heath Jr
Summary: This paper presents a unified model for tightly-coupled massive MIMO systems, which consist of a large number of tightly integrated antennas in a compact space. By considering mutual coupling as a friendly factor rather than a detrimental one, we show that tight coupling widens the operational bandwidth of antenna arrays, leading to a missing MIMO gain known as the bandwidth gain. Additionally, we derive the optimum spacing-to-antenna-size ratio and optimize the antenna array size to maximize achievable rate.
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Dohyun Kim, Miguel R. Castellanos, Robert W. Heath
Summary: This article proposes a deep reinforcement learning-based policy for joint relay selection and beam management, which can efficiently select unblocked relays and adapt to changing channel and traffic patterns.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Dong-Hyun Jung, Gyeongrae Im, Joon-Gyu Ryu, Seungkeun Park, Heejung Yu, Junil Choi
Summary: Megaconstellations of LEO satellites are being considered as a solution for global coverage with low latency and high throughput. However, as the number of satellites and operators increases, inter-satellite interference becomes a concern. This article introduces the concept of satellite clusters that can enhance network performance through cooperative transmissions. Simulation results show that clustered networks outperform unclustered ones, and viable network architectures are proposed based on 3GPP standards. The future applications of clustered satellite networks are also discussed.
IEEE VEHICULAR TECHNOLOGY MAGAZINE
(2023)
Article
Computer Science, Information Systems
Mohamed Habib Loukil, Miguel R. Castellanos, Arupjyoti Bhuyan, Robert W. W. Heath Jr
Summary: In this paper, the application of low-resolution converters in wireless devices using 1-bit binary signals and Gaussian signals is studied. Two different signaling methods are proposed, and closed-form expressions for the secrecy rate and near-optimal algorithms are provided. Power is allocated primarily to the main signal at low signal-to-noise ratios, and optimal power allocation is effective only at high SNR. Additionally, knowledge of the eavesdropper channel greatly enhances system secrecy.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2023)
Correction
Computer Science, Information Systems
Hyuckjin Choi, Jaeky Oh, Jaehoon Chung, George C. Alexandropoulos, Junil Choi
Article
Optics
Yukun Wang, Si Chen, Kan Lin, Xi Chen, Zhengyang Xu, Shiliang Lou, Xin Ge, Guangming Ni, Xiaojun Yu, Jianhua Mo, Quanquan Mu, Linbo Liu
Summary: Multi-channel detection is an effective way to improve data throughput of spectral-domain optical coherence tomography (SDOCT). However, the current approach using multiple detectors increases system complexity and cost. We propose a novel multi-channel detection design based on a single spectrometer, which broadens the spectral bandwidth of each pixel, reducing relative intensity noise (RIN). The theoretical and experimental analysis shows that this design effectively improves sensitivity, especially for systems dominated by electrical noise or RIN.
CHINESE OPTICS LETTERS
(2023)
Article
Computer Science, Information Systems
Hyuckjin Choi, Jaeky Oh, Jaehoon Chung, George C. Alexandropoulos, Junil Choi
Summary: This paper presents a novel three-dimensional (3D) ray-tracing simulator called WiThRay for performance assessment in smart wireless environments. WiThRay incorporates reconfigurable intelligent surfaces (RISs), which are key for RIS-enabled smart wireless communications. Channel data obtained from WiThRay matches well with the fundamental EM propagation theory.