Article
Engineering, Electrical & Electronic
Yunlong Cai, Ming-Min Zhao, Kaidi Xu, Rui Zhang
Summary: This paper investigates the passive beamforming and deployment design for an intelligent reflecting surface (IRS) aided full-duplex (FD) wireless system. The goal is to minimize the transmit power consumption of the system by optimizing the transmit power and reflection coefficients, subject to rate constraints and uni-modulus constraints. The analysis shows that the FD system outperforms the HD system, and the distributed deployment is more effective than the centralized deployment. An efficient algorithm based on the block coordinate descent (BCD) method is proposed to solve the power minimization problem.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Computer Science, Hardware & Architecture
Zhi Chen, Boyu Ning, Chong Han, Zhongbao Tian, Shaoqian Li
Summary: Terahertz (THz) communications are seen as a promising candidate for future 6G wireless networks, but face challenges such as propagation loss, signal blockage, and hardware cost. The emerging paradigm of intelligent reflecting surface (IRS)-assisted THz communications aims to enhance communication quality and reduce overhead through joint active and passive beamforming. Various approaches for THz active/passive beam steering and beam training strategies are discussed, along with envisioned scenarios integrating IRS into THz communications, while pointing out open challenges and future research directions for this new paradigm.
IEEE WIRELESS COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Sai Xu, Jiajia Liu, Yurui Cao, Jingyi Li, Yanning Zhang
Summary: This paper proposes an intelligent reflecting surface (IRS) empowered secure cooperative transmission strategy for satellite-terrestrial integrated networks, which can significantly reduce the target SINR at the eavesdropper, achieving a great secrecy gain.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2021)
Article
Computer Science, Information Systems
Muhamad Mustaghfirin, Keshav Singh, Sudip Biswas, Wan-Jen Huang
Summary: An intelligent reflecting surface (IRS) is an array of passive reflecting elements that has the potential to extend transmission coverage in future communication networks. Results from the analysis show that IRS-aided communication outperforms decode and forward (DF) relay in various scenarios, especially when the number of users is high or transmit power is increased. Increasing the number of elements in an IRS leads to better user service quality, and IRS-aided communication demonstrates better energy efficiency for higher quality of service requirements compared to other scenarios.
Article
Computer Science, Information Systems
Sai Xu, Jiajia Liu, Yurui Cao
Summary: This article introduces a novel strategy for secure transmission using intelligent reflecting surfaces (IRS) as backscatter devices. By modulating and reflecting jamming signals, this strategy can deteriorate the reception of illegitimate users without affecting the communication of legitimate users, thus ensuring the security of the transmission.
IEEE INTERNET OF THINGS JOURNAL
(2022)
Article
Computer Science, Information Systems
Xiaowei Pang, Weidong Mei, Nan Zhao, Rui Zhang
Summary: This research proposes a scheme to mitigate air-ground interference in the integration of unmanned aerial vehicles (UAVs) into cellular networks. By tuning the passive beamforming of intelligent reflecting surfaces (IRSs), interference from base stations to UAVs can be suppressed in the downlink, and interference from UAVs can be suppressed or enhanced in the uplink for interference cancellation. A hybrid interference cancellation scheme is also proposed to maximize the weighted sum rate of UAVs and ground users by optimizing the set of base stations and UAV's transmit power.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Meng Hua, Qingqing Wu, Derrick Wing Kwan Ng, Jun Zhao, Luxi Yang
Summary: This article investigates intelligent reflecting surface (IRS)-aided multicell wireless networks and proposes a joint optimization scheme to maximize the minimum achievable rate of cell-edge users. By transforming the non-convex max-min problem into an equivalent form using a compromise method, an efficient suboptimal iterative algorithm is designed. The optimization methods for single-user and multiuser scenarios are also discussed, showing significant performance improvement and outperformance compared to conventional designs in terms of max-min rate.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Miao Jiang, Yiqing Li, Guangchi Zhang, Miao Cui
Summary: In this study, the maximization of achievable rate region in intelligent reflecting surfaces (IRSs)-assisted interference channel (IFC) is investigated. A novel optimization approach is proposed to obtain the Pareto boundary of the achievable rate region in IFC by optimizing transmit power and passive beamforming vectors at all the IRSs. The proposed methods significantly reduce computational complexity compared to conventional SDR-based algorithms.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Qiang Li, Silei Wang, Yinyin Wang
Summary: This correspondence investigates the use of intelligent reflecting surface (IRS) for multiuser multi-input single-output (MISO) downlink multicast beamforming in 6G communications. The study proposes the utilization of rank-two beamforming with Alamouti assistance at the base station (BS), and a joint optimization of the beamforming and IRS phase shift to minimize transmit power while ensuring signal-to-noise ratio at users. The nonconvex power minimization problem is approached with a custom-derived proximal distance algorithm (PDA) with generalized power method (GPM). Simulation results show that rank-two beamforming achieves lower power and reduced computation complexity compared to rank-one beamforming.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Jung-Chieh Chen
Summary: This article explores an intelligent reflecting surface (IRS)-assisted communication system to enhance spectral efficiency by optimizing transmit and reflect beamforming. It introduces manifold optimization (MO) and gradient projection algorithm to address reflect beamforming, achieving low complexity and high efficiency goals.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2021)
Article
Computer Science, Hardware & Architecture
Na Chen, Chengbo Liu, Haohui Jia, Minoru Okada
Summary: This article investigates the progress and potential of intelligent reflecting surface (IRS)-aided networks for 6G systems affected by interference. It identifies the deployment and efforts to suppress interference in different 6G scenarios. The advantages of IRS are explored, and recent works on various interference mitigation schemes are summarized.
Article
Engineering, Electrical & Electronic
Yunbo Hu, Kai Kang, Hongbin Zhu, Xiliang Luo, Hua Qian
Summary: This paper investigates the mobility adaptation problem of mobile UEs in a massive MIMO system with the assistance of IRS. A beam control method is proposed to reduce the frequency of updating beamforming matrices and achieve satisfactory performance.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Computer Science, Information Systems
Shaocheng Huang, Yu Ye, Ming Xiao, H. Vincent Poor, Mikael Skoglund
Summary: In this study, a decentralized cooperative beamforming framework for cell-free networks aided by intelligent reflecting surfaces (IRS) is proposed to increase system sum-rate efficiently. The proposed method outperforms existing decentralized methods and asymptotically approaches the performance of centralized optimization as the number of iterations increases.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2021)
Article
Computer Science, Information Systems
Yi Zhou, Cunhua Pan, Phee Lep Yeoh, Kezhi Wang, Zheng Ma, Branka Vucetic, Yonghui Li
Summary: This letter investigates a VR delivery system that reduces latency and ensures security by using an intelligent reflecting surface (IRS). By jointly optimizing transmission policies and adjusting parameters, the latency for all users has been successfully minimized.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2022)
Article
Telecommunications
Yanzhen Liu, Qiyu Hu, Yunlong Cai, Markku Juntti
Summary: This letter investigates an intelligent reflecting surface aided device-to-device offloading system, proposing a novel algorithm for joint design of beamforming and resource allocation to reduce system latency.
IEEE COMMUNICATIONS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Dong Li, Rui Ma, Xiayu Wang, Jin Hu, Maliang Liu, Zhangming Zhu
Summary: This paper presents a direct time-of-flight image LiDAR technology for realizing a reliable autopilot system. The system is based on hardware architecture and processing algorithm using field programmable logic array (FPGA). The processing algorithm includes multi-channel time-to-digital converters (TDCs), equivalent sampling technology, correlation slope fitting algorithm, and stray light suppression algorithm.
IEEE SENSORS JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
Yang Liu, Yihan Zhao, Jin Hu, Rui Ma, Dong Li, Xiayu Wang, Maliang Liu, Zhangming Zhu
Summary: In this article, we propose an accurate procedure for predicting the photon detection probability (PDP) for single-photon avalanche diodes (SPADs). The energy threshold needed for triggering impact ionization, that is, the dead space, was carefully considered and developed into a 2-D solution. Two sets of SPADs based on different materials were fabricated and tested, and the simulation and experimental results are in accordance with each other. This procedure makes device optimization based on simulation results easy and efficient.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Electrical & Electronic
Jin Hu, Xiayu Wang, Dong Li, Yang Liu, Rui Ma, Zhangming Zhu
Summary: This article presents a small and low-power voltage-controlled ring oscillator (VCRO) based Time-To-Digital converter (TDC) for Flash Light Detection and Ranging (LiDAR) applications. The TDC is designed with compact local phase interpolators (PIs) to improve resolution and a non-reset operation mode for increased linearity. It has been fabricated in a 0.18-mu m HV-CMOS technology achieving a resolution of 50 ps. A Phase Lock Loop (PLL) is used to track PVT variations, and a power-saving analog buffer is employed for stable control voltage distribution. The TDC exhibits good linearity and array uniformity for Flash LiDAR applications.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2022)
Article
Engineering, Electrical & Electronic
Xiayu Wang, Yang Liu, Jin Hu, Dong Li, Rui Ma, Zhangming Zhu
Summary: An analog SiPM-based receiver with wideband TIA is proposed for direct ToF LiDAR applications. The receiver achieves a wider -3 dB bandwidth and high ranging accuracy, making it suitable for long range LiDAR measurements.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2023)
Article
Engineering, Electrical & Electronic
Jin Hu, Dong Li, Xiayu Wang, Rui Ma, Yang Liu, Zhangming Zhu
Summary: This brief introduces a robust continuous running voltage-controlled ring oscillator-based (VCRO-based) time to digital converter (TDC) for Light Detection and Ranging (LiDAR) applications. A robust two-counter method with a hybrid structure counter is proposed to avoid any sampling errors. To reduce the TDC dead time, a two-interleaved sampling channel is adopted. Measurement results show negligible error rate, with peak-to-peak INL and DNL of 2.08 LSB and 0.46 LSB, respectively.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Engineering, Electrical & Electronic
Jiaji Ma, Xiayu Wang, Rui Ma, Jin Hu, Dong Li, Yang Liu, Zhangming Zhu
Summary: This brief introduces a mixed calibration method for Time-to-Digital Converters (TDC) in LiDAR applications. The method utilizes a feedback loop consisting of a VCRO-based TDC, DDAC, encoder, sampling circuit, LSB-first algorithm (LSBFA) block, and analog buffer. The DDAC output is automatically adjusted based on an external input frequency control code (FCC) to ensure accuracy. A voltage coverage strategy is proposed to meet the accuracy requirements, and a voltage trimming approach is used to avoid drastic switching activity. The TDC achieves a peak-to-peak INL of 1.81 LSB and DNL of 0.44 LSB.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Engineering, Electrical & Electronic
Dong Li, Jin Hu, Rui Ma, Xiayu Wang, Yang Liu, Zhangming Zhu
Summary: This brief introduces a LiDAR imager that utilizes a single-photon avalanche diode (SPAD) image sensor with a resolution of 32 x 32, a VCSEL-based laser emission system with the same resolution and pixel spacing, and a FPGA for calibration and control. By driving the image sensor and utilizing a gating high-voltage driver circuit, background noise interference is reduced, and real-time accuracy calibration is achieved for the time-to-digital converter (TDC) with a resolution of 200 ps. The proposed LiDAR imager also incorporates a common-cathode driver circuit with narrow pulse, adaptive frequency, and power regulation to enhance the signal-to-noise ratio and reduce power consumption. The LiDAR imager can achieve depth imaging up to 10 m with a repeatability error of 10 cm at 10 frames/s.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Engineering, Electrical & Electronic
Sun Mao, Kun Yang, Jie Hu, Dong Li, Dapeng Lan, Ming Xiao, Youzhi Xiong
Summary: Wireless powered hybrid backscatter-active communications are studied in this paper. Multiple sensor devices, powered by a power beacon, transmit their information to an access point using backscatter and active communications with the assistance of an intelligent reflecting surface. The proposed method optimizes the system energy efficiency by jointly optimizing the phase shifts of the intelligent reflecting surface, time allocation for communications, and transmit power of the devices. Simulation results show that the proposed method outperforms existing benchmark methods in terms of system energy efficiency.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Bowen Gu, Dong Li, Yongjun Xu, Chunguo Li, Sumei Sun
Summary: In this paper, we investigate and analyze the full-duplex-based backscatter communications with multiple backscatter devices. We aim to maximize the total energy efficiency of the system by considering the causality and non-linearity of energy harvesting. To solve the non-convex problem, we reformulate it using the Dinkelbach's method and design an alternative iterative algorithm. Simulation results show that the proposed algorithm achieves a much better energy efficiency than the benchmark algorithms.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Computer Science, Information Systems
Hehao Niu, Zhi Lin, Zheng Chu, Zhengyu Zhu, Pei Xiao, Huan X. X. Nguyen, Inkyu Lee, Naofal Al-Dhahir
Summary: This article focuses on the study of secure communication in an IoT network. It introduces the use of active refracting RIS-based transmitter and passive reflective RIS to enhance secrecy performance in the presence of multiple eavesdroppers. The goal is to maximize the weighted sum secrecy rate through joint optimization of power allocation, transmit beamforming, and phase shifts. The proposed linearization and alternating optimization schemes provide effective solutions to the nonconvex optimization problem. Simulation results demonstrate the effectiveness of the proposed design.
IEEE INTERNET OF THINGS JOURNAL
(2023)
Letter
Engineering, Aerospace
Yongcai Liu, Liang Zhou, Fangmin He, Dong Li, Jin Meng
Summary: This article studies the probabilistic analysis of amplitude-phase error tolerance for cross-eye jamming. By demonstrating that the contours of cross-eye gain can be approximate to a set of ellipses, the probability distributions of cross-eye gain and angle factor are derived, based on the assumption that the amplitude-phase errors of cross-eye jammer are Gaussian distributed. The article presents the instructions to determine the required standard deviation of the amplitude-phase error to produce a specific confidence level of cross-eye jamming performance metric.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Xiayu Wang, Rui Ma, Dong Li, Jin Hu, Zhangming Zhu
Summary: This article proposes a wide dynamic range analog front-end (AFE) circuit for direct time-of-flight (dToF) LiDAR applications. A reconfigurable transimpedance amplifier (TIA) with gain control scheme is introduced to significantly increase the linear dynamic range. A feedforward compensation technique is proposed to improve the stability of the TIA and extend the bandwidth. The post amplifier is presented with active feedback to further improve the entire gain and mitigate the attenuation of the bandwidth. The proposed AFE is fabricated in 0.18 μm CMOS technology, achieving -3 dB bandwidth, maximum transimpedance gain, linear dynamic range, and input-referred noise current of 260 MHz, 100 dBO, 79.3 dB, and 3.3 pA/vHz, respectively.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Computer Science, Information Systems
Zhichao Zhang, Dong Li, Yangfan He, Yunjie Chen, Jianwei Zhang, Chengxi Zhou
Summary: In order to address the challenge of processing high-dimensional complex features information, this study extends the permanent scale Wigner distribution and the single scale k-Wigner distribution to a novel multiscale parameterized Wigner distribution called K-Wigner distribution (KWD). The KWD can extract different types of features at different dimensions using different scales. Uncertainty inequalities of the KWD are established, providing the tightest universal attainable lower bound for all functions on the uncertainty product in time-KWD and Fourier transform-KWD domains. The obtained results solve the concern regarding the limit of the KWD's time-frequency resolution influenced by the parameter matrix.
IEEE TRANSACTIONS ON INFORMATION THEORY
(2023)
Article
Engineering, Electrical & Electronic
Hehao Niu, Zhi Lin, Kang An, Xiaohu Liang, Yihua Hu, Dong Li, Gan Zheng
Summary: This study proposes a physical-layer security scheme for a cognitive-satellite terrestrial network, where an active reconfigurable intelligent surface (RIS) is deployed to enhance secure transmission and suppress interference. An alternating optimization scheme is used to jointly optimize the beamformer, artificial noise, and the reflecting coefficient. Simulation results show that the active RIS significantly improves secrecy performance compared to passive RIS and no RIS designs, relieving the impact of double fading.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
