Article
Engineering, Aerospace
Tom Tirer, Oded Bialer
Summary: The article focuses on the problem of estimating the direction of arrival (DOA) of sources in aerospace and vehicular communication, localization, and radar. It proposes an optimization scheme based on joint sparse and low-rank matrices to solve the problem, utilizing the alternating direction method of multipliers and the accelerated proximal gradient techniques. The article also demonstrates the advantages of estimating the subarrays' phase shifts and applying a coherent DOA estimation method.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2022)
Article
Computer Science, Information Systems
Song Noh, Jiho Song, Junse Lee, Heejung Yu
Summary: This paper investigates the problem of direction-of-arrival (DoA) estimation for a hybrid array of subarrays in millimeter-wave communication systems. The proposed method jointly exploits multiple outputs in the time domain for high-resolution DoA estimation. It designs an optimal hybrid combiner to maximize beamforming gain and reduces receiver complexity with block-wise processing. The performance of the proposed method and its extension to a uniform planar array case are analyzed, and the numerical results demonstrate its effectiveness.
Article
Engineering, Electrical & Electronic
Ziyu Guo, Weizhen Wang, Xiaodong Wang, Xiaoyang Zeng
Summary: This article introduces an efficient hardware beamspace DoA estimator for unequal-sized subarrays. By optimizing the algorithm and hardware design, the number of multiplication operations is reduced by 75% without significant performance loss. Experimental results show that the proposed hardware architecture achieves a small core area and high clock frequency in 28-nm technology.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2022)
Review
Engineering, Multidisciplinary
Yi Huang, Yaochun Shen, Jiayou Wang
Summary: THz technology is a key enabling technology for both imaging and wireless communications, and it is expected to be used in 6G and future wireless communication systems.
Article
Engineering, Electrical & Electronic
Hang Zheng, Chengwei Zhou, Zhiguo Shi, Yujie Gu, Yimin D. Zhang
Summary: In this paper, a coarray tensor DOA estimation algorithm for multi-dimensional structured sparse arrays is proposed, and an optimal coarray tensor structure for source identifiability enhancement is investigated.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2023)
Article
Chemistry, Analytical
Murdifi Muhammad, Minghui Li, Qammer Abbasi, Cindy Goh, Muhammad Ali Imran
Summary: This paper investigates an accurate and high-resolution technique for direction of arrival (DOA) estimation using a single snapshot of data. By manipulating signal covariance matrix and suppressing unwanted noise, the proposed technique outperforms existing methods in various signal-to-noise ratio scenarios. It also achieves the best DOA estimation results in single snapshot and single-source scenarios.
Article
Engineering, Electrical & Electronic
D. Veerendra, Babur Jalal
Summary: This article presents a DOA estimation method using the fast variable step size least mean square (FVSSLMS) method. By modifying the structure of the uniform linear array (ULA), the proposed method provides uniform estimation performance for all DOAs with reduced computation complexity.
IEEE SENSORS JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
Uzma M. Butt, Shoab A. Khan, Anees Ullah, Abdul Khaliq, Pedro Reviriego, Ali Zahir
Summary: A novel design approach for FPGA implementation of the MUSIC algorithm is proposed in this paper, which significantly reduces both FPGA resources and latency.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2021)
Article
Computer Science, Information Systems
Hanting Mo, Yi Tong, Yanjiao Wang, Kaiwei Wang, Dongxiang Luo, Wenlang Li
Summary: A novel method based on sparse non-uniform linear antenna array is proposed for estimating the direction of arrival (DOA). By using a specific configuration scheme and several algorithms, the proposed method can improve the estimation accuracy while eliminating the impact of noise.
Article
Optics
Yan Wang, Shaohe Li, Hui Wang, Bowen Tan, Xingcheng Xiang, Runfeng Su, Caihong Zhang, Biaobing Jin, Jian Chen, Peiheng Wu
Summary: PB metasurfaces show superior performance in the THz region with an ultra-thin structure, achieving broadband and efficient wavefront manipulation. By spatially rotating orientation, beam steering and superposition of vortex waves can be achieved.
Article
Engineering, Electrical & Electronic
Lu Sun
Summary: In this article, two improved coprime arrays (CAs), ImCAAM1 and ImCAAM2, are proposed for direction of arrival (DOA) estimation, which can generate a longer consecutive difference co-array. Both designs solve the problem of invalid use of part of lags in difference co-array when considering moving sparse array. The first scheme involves compressing the interelement spacing of one subarray and staggering a certain distance between two subarrays to increase consecutive degrees of freedom (cDOF). The second scheme further fills the remaining holes at both ends of the virtual array by adjusting the interelement spacing and staggering distance between subarrays.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Electrical & Electronic
Pinjiao Zhao, Qisong Wu, Zhengyu Chen, Guobing Hu, Liwei Wang, Liangtian Wan
Summary: Sparse arrays have advantages in element layout and degrees of freedom, which can estimate more sources than the number of sensors with high accuracy. However, the array configuration may affect the virtual coarray and uniform degrees of freedom when the positions of sensors change. In this paper, a generalized nested array (GNA) configuration family is proposed, which provides flexible element arrangements. The GNA family has no hole in the difference coarray and performs well in DOA estimation using compressive sensing.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Computer Science, Information Systems
Youngwoo Youn, Jeongphill Kim, Sangyeol Oh, Sang-Hwa Yi
Summary: A new approach for estimating the direction-of-arrival in a Time-Modulated Array system with a bipolar squared periodic time-modulating sequence is proposed, which enhances the power of harmonic components in the received signal. A new parameter related to the ratio of upper and lower sideband first harmonic components is formulated to improve DOA estimation accuracy in low SNR environments, with numerical analysis verifying its effectiveness.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2021)
Article
Computer Science, Information Systems
Parth Mehta, Kumar Appaiah, Rajbabu Velmurugan
Summary: A new spatial IIR beamformer based direction-of-arrival (DoA) estimation method is proposed, which improves the performance parameters of a beamformer. The proposed method outperforms the previous feedback beamforming approach and the conventional beamformer. By incorporating a retransmission based minimum variance distortionless response (MVDR) beamformer, the proposed method achieves lower estimation error compared to prior methods such as MUSIC, ESPRIT, robust MVDR, nested-array MVDR, and reduced-dimension MVDR methods, especially at low SNR levels.
Article
Environmental Sciences
Liya Xu, Jianjun Huang, Hao Zhang, Bin Liao
Summary: With the rapid development of vibration and noise reduction technologies, underwater target detection, especially high-resolution DOA estimation with sonar array, is facing great challenges. In this paper, a new approach is proposed to construct a large-aperture virtual array with multiple small-aperture arrays of UUVS. The matrix completion technique is employed to recover the unobserved and corrupted data, and the recovered matrix is then used for underwater target bearing estimation using the traditional DOA estimation approach. Numerical results show that the proposed method is capable of detecting underwater targets with high precision and resolution.
Article
Engineering, Electrical & Electronic
Ian F. Akyildiz, Chong Han, Zhifeng Hu, Shuai Nie, Josep Miquel Jornet
Summary: This paper reviews the research achievements of THz band communications in the past decade and identifies the open challenges that need to be addressed, covering various aspects such as devices, channel behavior, communication and networking, and physical testbeds. These research findings will serve as the foundation for 6G and Beyond wireless systems in the next decade.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Longfei Yan, Chong Han, Jinhong Yuan
Summary: This paper introduces a novel DS-FTTD structure to address the beam squint issue in hybrid beamforming, and proposes a low-complexity RD algorithm to design hybrid beamforming matrices, which can significantly improve energy efficiency and array gain.
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Tianqi Mao, Jiaxuan Chen, Qi Wang, Chong Han, Zhaocheng Wang, George K. Karagiannidis
Summary: This paper investigates the waveform design for joint radar sensing and communication systems in the millimeter-wave and low terahertz bands. A novel multi-subband quasi-perfect sequence is proposed for accurate target ranging and velocity estimation, while eliminating the influence of strong Doppler shift. Furthermore, a data-embedded waveform is constructed to enable simultaneous interference-free sensing and communication.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Yongzhi Wu, Filip Lemic, Chong Han, Zhi Chen
Summary: In this work, a sensing integrated discrete Fourier transform spread orthogonal frequency division multiplexing (SI-DFT-s-OFDM) system is proposed for THz ISAC, which can provide lower peak-to-average power ratio than OFDM and is adaptive to flexible delay spread of the THz channel. A deep learning based ISAC receiver with two neural networks is developed to recover transmitted data and estimate target range and velocity, while mitigating the imperfections and non-linearities of THz systems. Extensive simulation results demonstrate that the proposed deep learning methods can realize mutually enhanced performance for communication and sensing, and is robust against Doppler effects, phase noise and multi-target estimation.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Akram Shafie, Nan Yang, Chong Han, Josep M. Jornet
Summary: This paper presents a novel spectrum allocation strategy for multiuser terahertz band communication systems. This strategy allows users to occupy sub-bands with unequal bandwidths and optimally avoids using spectra with high molecular absorption loss. Numerical results demonstrate the effectiveness of this strategy.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Yuanbo Li, Yi Chen, Dong Yan, Ke Guan, Chong Han
Summary: To support intelligent vehicular services, high-speed communications from vehicles to infrastructure (V2I) are needed in vehicular ad-hoc networks (VANET). The Terahertz (THz) band, which has abundant spectrum resources, is considered promising for this purpose. However, channel modeling for THz V2I communications is a challenge. In this paper, ray-tracing techniques are used to analyze the V2I channel at 300 GHz in an urban scenario, and a novel ray-tracing assisted stochastic channel model (RTA-SCM) is proposed.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Renwang Li, Shu Sun, Yuhang Chen, Chong Han, Meixia Tao
Summary: Reconfigurable intelligent surfaces (RISs) are a prospective technology for next-generation wireless networks, offering potential in coverage and capacity enhancement. This study focuses on the achievable rate of RIS-assisted multiple-input multiple-output communication systems in the millimeter-wave band with limited scattering. An upper bound of the achievable rate is derived using majorization theory and Jensen's inequality, and optimization algorithms are proposed to maximize the achievable rate. Simulation results validate the effectiveness of the proposed algorithms.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Longfei Yan, Chong Han, Nan Yang, Jinhong Yuan
Summary: In this paper, an energy-efficient dynamic-subarray with fixed phase shifters (DS-FPS) architecture is proposed for terahertz hybrid beamforming, which compensates for the spectral efficiency loss caused by the fixed phase of FPS through a switch network and designs the hybrid beamforming matrices using a row-successive-decomposition (RSD) algorithm. 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 higher energy efficiency and robustness to CSI error compared to existing architectures.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2023)
Article
Mathematics
Yue Huang, Lijuan Sun, Chong Han, Jian Guo
Summary: By using raw legal judgments as information and proposing a two-stage text-summarization model to handle different granularities of information, this study effectively captured essential and relevant information from lengthy legal texts and generated better legal judgment summaries. The model achieved an overall 0.19-0.41 improvement in its ROUGE score compared to the baseline models, demonstrating its effectiveness.
Article
Engineering, Electrical & Electronic
Boyu Ning, Zhongbao Tian, Weidong Mei, Zhi Chen, Chong Han, Shaoqian Li, Jinhong Yuan, Rui Zhang
Summary: This paper provides a review of beamforming technologies for terahertz ultra-massive multiple-input-multiple-output (UM-MIMO) systems. It presents the system model, channel parameters, and discusses the far-field and near-field assumptions in terahertz UM-MIMO. The beam training strategy in terahertz band is introduced, along with codebook design approaches. The paper also explores intelligent-reflecting-surface (IRS)-assisted joint beamforming and multi-user beamforming in terahertz UM-MIMO systems.
IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY
(2023)
Proceedings Paper
Computer Science, Information Systems
Guochao Song, Yuanbo Li, Jiamo Jiang, Chong Han, Ziming Yu, Ying Du, Zhiqin Wang
Summary: This paper conducts measurement campaigns in a data center scenario to analyze and study the characteristics of THz wave propagation, including path loss and shadow fading. The results show that reflections and scattering from metal racks in the data center significantly affect the signal propagation.
2022 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM 2022)
(2022)
Proceedings Paper
Telecommunications
Yuanbo Li, Yiqin Wang, Yi Chen, Ziming Yu, Chong Han
Summary: In this paper, a measurement campaign is conducted in the THz band to investigate the channel characteristics. The channel impulse response and power-delay-angle profile are obtained, and multipath components are extracted and analyzed. The resulting numerology is helpful for guiding the design of THz communication systems.
IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC 2022)
(2022)
Proceedings Paper
Telecommunications
Yuhang Chen, Renwang Li, Chong Han, Meixia Tao
Summary: Terahertz (0.1-10 THz) communications are considered crucial for 6G ultra-high-speed wireless systems. Integrated ultra-massive multiple-input multiple-output (UM-MIMO) and intelligent reflecting surface (IRS) systems can overcome limited coverage and line-of-sight blockage. However, challenges arise due to mismatched dimension of antenna arrays and wavelength, as well as the impact of channel sparsity on capacity.
IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC 2022)
(2022)
Proceedings Paper
Telecommunications
Yongzhi Wu, Chong Han, Zhi Chen
Summary: This paper proposes a DFT-s-OTFS system for THz ISAC, which includes a two-stage sensing parameter estimation algorithm. The system achieves high accuracy in range and velocity estimation, improves power amplifier efficiency, and enhances sensing accuracy and bit error rate performance.
IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC 2022)
(2022)
Proceedings Paper
Telecommunications
Akram Shafie, Nan Yang, Sheeraz Alvi, Chong Han, Salman Durrani, Josep M. Jornet
Summary: This paper proposes a new spectrum allocation strategy for terahertz (THz) band communication systems. The strategy utilizes adaptive sub-band bandwidth to reduce loss variations and improve data rate performance.
IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC 2022)
(2022)