Article
Chemistry, Multidisciplinary
Jun Li, Tong Gao, Bo He, Wenjing Zheng, Fei Lin
Summary: Non-orthogonal multiple access (NOMA) technology allows multiple users to share the same time-frequency resource for signal transmission, leading to improved spectral efficiency and throughput. This study focuses on user grouping and power allocation in the downlink of a multi-carrier NOMA system, with the optimization goal being the sum rate. The proposed step-by-step optimization method includes improving the user grouping approach to avoid grouping users with similar channel gains and utilizing a deep learning power allocation algorithm. The simulation results demonstrate that the deep learning power allocation method outperforms the fractional transmit power allocation and fixed power allocation methods, enhancing the system's sum rate by about 2.2% and 19%, respectively. Additionally, the power allocation methods proposed in this study achieve approximately a 10% improvement in the system's sum rate compared to the fractional transmit power allocation method used among subcarriers and between multiplexed users.
APPLIED SCIENCES-BASEL
(2023)
Article
Computer Science, Information Systems
Hye Yeong Lee, Soo Young Shin
Summary: This study introduces a novel downlink non-orthogonal multiple access (NOMA) scheme using phase rotation to improve the trade-off between capacity and error performance in NOMA systems. By rotating and multiplexing symbols within each subgroup and superposing signals from two independent subgroups, the number of successive interference cancellation (SIC) operations are reduced. Numerical results demonstrate the improved performance of the proposed NOMA scheme over conventional NOMA and orthogonal multiple access (OMA).
Article
Telecommunications
Navideh Ghafouri, Naser Movahhedinia, Mohammad Reza Khayyambashi
Summary: This paper proposes a user grouping scheme for non-orthogonal multiple access (NOMA) systems, which has high data rate and low interference, and is able to accommodate users with different channel gains and powers.
WIRELESS PERSONAL COMMUNICATIONS
(2022)
Article
Computer Science, Information Systems
Haitham Al-Obiedollah, Kanapathippillai Cumanan, Haythem Bany Salameh, Gaojie Chen, Zhiguo Ding, Octavia A. Dobre
Summary: The MC-NOMA system divides the available bandwidth into sub-bands and serves multiple users in each sub-band using non-orthogonal multiple access. A technique for jointly allocating power and bandwidth with opportunistic sharing between sub-bands is proposed, utilizing a second-order cone program to address non-convexity issues in optimization. Simulation results demonstrate that the MC-NOMA system with opportunistic bandwidth allocation outperforms schemes with equal bandwidth allocation in terms of achieved sum-rate.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2021)
Article
Computer Science, Information Systems
Hongjiang Lei, Rui Gao, Zhi Ren, Ki-Hong Park, Gaofeng Pan, Mohamed-Slim Alouini
Summary: This study investigates the Meta distributions of secrecy rate in downlink NOMA systems with randomly located eavesdroppers. By approximating the MDs for NOMA users with Beta approximation, analytical expressions for the first two moments of conditional secrecy connection probability of NOMA users are derived, while considering perfect/imperfect successive interference cancellations on the near user. The accuracy of the results is verified through Monte Carlo simulations, showing that the MD can capture the statistics of the secrecy rate in a given secrecy connection probability.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Hao Cheng, Yili Xia, Yongming Huang, Luxi Yang
Summary: This paper investigates the achievable rate improvement for the downlink non-orthogonal multiple access (NOMA) system using the improper Gaussian signaling (IGS) technique. The users' data rates are formulated in terms of the impropriety degree of the IGS, under the imperfect successive interference cancellation (SIC). Joint optimization of power and impropriety degree is performed to determine the best transmission strategy.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Computer Science, Information Systems
Panagiotis Georgakopoulos, Tafseer Akhtar, Christos Mavrokefalidis, Ilias Politis, Kostas Berberidis, Stavros Koulouridis
Summary: The proposed scheme combines JT-CoMP and NOMA techniques in a C-RAN system to address limited wireless communication resources and severe interference issues. Simulation results confirm the scheme's improvement in user throughput, especially enhancing the performance of users with poor channel quality.
Article
Computer Science, Information Systems
Abdelrahman Abushattal, Saud Althunibat, Marwa Qaraqe, Huseyin Arslan
Summary: This study introduces a novel secure NOMA scheme based on physical-layer security concepts to enhance the security level against potential internal eavesdroppers. By exploiting random and independent channel characteristics to induce different phase shifts in each user's symbol, the proposed scheme effectively degrades the eavesdropper's performance without impacting legitimate users, ensuring data confidentiality for each user.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Yanyu Cheng, Kwok Hung Li, Yuanwei Liu, Kah Chan Teh, H. Vincent Poor
Summary: This paper investigates IRS-aided NOMA and OMA networks, analyzing the channel statistics of the BS-IRS-UD link, deriving mathematical expressions for outage probability and ergodic rate, and discussing diversity order and high SNR slope. The results show that IRS has significant advantages under specific conditions.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Do-Yup Kim, Hamid Jafarkhani, Jang-Won Lee
Summary: This paper investigates dynamic resource scheduling in downlink multi-channel non-orthogonal multiple access systems. It develops a low-complexity algorithm that solves each time slot's subproblem for fast resource scheduling. The algorithm provides good performance with low computational complexity, making it suitable for practical systems.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Computer Science, Information Systems
Hakkeon Lee, Insik Jung, Jehyun Heo, Daesik Hong
Summary: This paper proposes a novel time-asynchronous non-orthogonal multiple access (TA-NOMA) scheme to control interference and improve spectral efficiency through intentional time offset. A pre-processing scheme based on singular value decomposition (SVD) is used to achieve superior spectral efficiency compared to conventional power-domain NOMA. Another notable feature is that TA-NOMA does not require user pairing.
IEEE WIRELESS COMMUNICATIONS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Ziad Qais Al-Abbasi, Khaled M. Rabie, Daniel K. C. So
Summary: This paper investigates the energy efficiency optimization of a two-tier CRAN downlink based on NOMA, using PPP distribution for base station number and locations, and proposing an optimized solution and two power allocation techniques. Simulation results demonstrate promising performance gains compared to existing approaches.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Baoyi Xu, Mingyan Kou, Zheng Xiang, Peng Ren, Xiaomeng Guo
Summary: This paper investigates a downlink non-orthogonal multiple access (NOMA) transmission system, proposing a novel network-coded interference cancellation (NCIC) scheme and an adaptive NCIC (A-NCIC) scheme. Expressions of the outage probability are derived and simulation results demonstrate the significant performance advantage of the proposed NCIC scheme in terms of outage probability over conventional SIC-based NOMA.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Donghyeon Kim, Haejoon Jung, In-Ho Lee
Summary: This paper proposes a deep neural network (DNN)-based joint user selection and power allocation technique for non-orthogonal multiple access (NOMA) systems. Through simulations, it is shown that the proposed scheme achieves comparable performances to the optimal solutions in terms of sum rate and outage rate, while requiring lower computational complexity.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Computer Science, Hardware & Architecture
Yutong Wu, Jianyue Zhu, Xiao Chen, Yu Zhang, Yao Shi, Yaqin Xie
Summary: This paper proposes a quality-of-service-based SIC order method and optimizes power allocation for maximizing the rate in the uplink NOMA system. The simulation results demonstrate the superiority of the proposed method compared to traditional orthogonal multiple access and exhaustive search.
Article
Engineering, Electrical & Electronic
Fengqian Guo, Hancheng Lu, Zhuojia Gu
Summary: This paper investigates the problem of user grouping in cell-free massive MIMO systems to reduce the complexity of channel estimation and decoding. The results show that user grouping can serve more users without increasing complexity. Furthermore, the proposed user grouping strategy can significantly reduce power consumption.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Computer Science, Information Systems
Hancheng Lu, Fangyu Zhang
Summary: This paper aims to improve resource utilization efficiency in network virtualization environments by introducing the metric of resource fragmentation degree and corresponding algorithms to reduce resource fragmentation and allow more virtual networks to be embedded in substrate networks.
IEEE TRANSACTIONS ON NETWORK AND SERVICE MANAGEMENT
(2022)
Article
Engineering, Electrical & Electronic
Zhuojia Gu, Hancheng Lu, Peilin Hong, Yongdong Zhang
Summary: This paper proposes a dual-connectivity sub-6 GHz and mmWave heterogeneous network architecture to improve the reliability of VR delivery. By analyzing the reliability of VR delivery, it is theoretically demonstrated that sub-6 GHz links can be used to enhance its reliability. The proposed algorithms for joint caching and computing optimization problem provide optimal and sub-optimal solutions.
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS
(2022)
Article
Telecommunications
Yazheng Wang, Hancheng Lu, Dan Zhao, Yansha Deng, Arumugam Nallanathan
Summary: This paper proposes an intelligent reflecting surface (IRS) assisted wideband millimeter wave (mmWave) communication system with lens antenna array. By optimizing the reflection coefficient matrices and beamforming vector, the system achieves high robustness, low complexity, and cost-effectiveness in mmWave communication.
IEEE TRANSACTIONS ON COGNITIVE COMMUNICATIONS AND NETWORKING
(2022)
Article
Engineering, Electrical & Electronic
Langtian Qin, Hancheng Lu, Feng Wu
Summary: Mobile edge computing (MEC) is a promising computing paradigm that brings strong computing, storage, and communication services to users. However, traditional cellular-based MEC suffers from signal attenuation and interference at the edge, resulting in reduced achievable rate, transmission outage, and offloading failure. To overcome this, we propose a user-centric MEC (UCMEC) framework that combines user-centric network (UCN) and MEC computing services. Through dense access point deployment, UCMEC provides efficient, reliable, and low-cost wireless transmission and edge computing services to users. By optimizing task partition, transmit power control, and computing resource allocation, we minimize energy consumption while meeting delay constraints, achieving lower energy consumption, lower delay, and higher successful offloading probability compared to traditional MEC.
IEEE COMMUNICATIONS MAGAZINE
(2023)
Article
Engineering, Electrical & Electronic
Lifang Wu, Xianglong Lang, Ye Xiang, Changwen Chen, Zun Li, Zhuming Wang
Summary: This paper proposes a novel end-to-end hierarchical relation inference framework based on active spatial positions for group activity recognition. The framework is able to locate active spatial positions and use them as visual tokens to infer the relations for token embeddings. Experimental results show that the proposed framework only requires individual bounding box labeling in the training stage and automatically eliminates background noise from the entire scene.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY
(2023)
Article
Computer Science, Information Systems
Jinyang Huang, Bin Liu, Chenglin Miao, Yan Lu, Qijia Zheng, Yu Wu, Jiancun Liu, Lu Su, Chang Wen Chen
Summary: Driven by various applications, recent achievements have been made in WiFi-based Human Activity Recognition (HAR) techniques that utilize WiFi infrastructures to infer human activities. However, the ubiquitous Co-channel Interference (CCI) poses a challenge to the performance of these systems. In this paper, a novel approach called PhaseAnti is proposed to exploit the CCI-independent phase component of WiFi Channel State Information (CSI) for HAR, which achieves superior effectiveness and recognition speed compared with existing solutions.
IEEE TRANSACTIONS ON MOBILE COMPUTING
(2023)
Article
Engineering, Electrical & Electronic
Chenwu Zhang, Hancheng Lu, Jinxue Liu
Summary: This paper proposes a deep learning-based detector for index modulation-aided MIMO systems. The detection process is formulated as a sparse reconstruction problem utilizing the attributes of IM, and a DL-based detector called IMRecoNet is designed to realize this sparse reconstruction process using complex value operations. Simulation results show that the proposed detector outperforms existing algorithms in terms of antenna recognition accuracy and bit error rate under various scenarios.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Engineering, Chemical
Chao Yang, Hancheng Lu, Zhe Li, Zilong Xu, Baoqing Liu
Summary: In this study, different turbulence models, drag models, and breakup and coalescence models were compared and optimized for a coaxial mixer. The RNG k-epsilon model had better accuracy in describing turbulent scale and gas-phase concentration. The Luo-Luo model effectively described the coalescence and breakup processes of bubbles. While the Ishii & Zuber and Brucato models performed well in predicting gas dispersion and flow structure, they still failed to capture the peak gas holdup. A new correlation was proposed to explain the increase in drag coefficient caused by turbulence, significantly improving gas holdup prediction accuracy.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Computer Science, Artificial Intelligence
Tiancheng Lin, Zhimiao Yu, Zengchao Xu, Hongyu Hu, Yi Xu, Chang-Wen Chen
Summary: Self-supervised representation learning has limitations when applied to whole-slide pathological images due to their unique characteristics. To address this issue, we propose a novel scheme called Spatial Guided Contrastive Learning (SGCL), which leverages spatial proximity and multi-object priors for stable self-supervision. SGCL outperforms state-of-the-art methods on diverse downstream tasks across multiple datasets.
MEDICAL IMAGE ANALYSIS
(2023)
Article
Biotechnology & Applied Microbiology
Zhe Li, Hancheng Lu, Zixuan Zhang, Baoqing Liu
Summary: The scale-up technology of anaerobic fermentation stirring equipment was studied using computational fluid dynamics (CFD) simulations under different solid content conditions. The applicability of different scale-up criteria, such as blade tip speed and Reynolds number, was analyzed and optimized. The results showed that when the solid content is less than 5%, scaling up according to the same Weber number is recommended. When the solid content is between 5% and 10%, scaling up based on the same blade tip speed is suitable, especially for conditions with limited shear rate. Scaling up according to the Reynolds number was not recommended due to poor mixing effect. The suitable scale-up indices for 5%, 10%, and 15% solid content in anaerobic fermentation systems were found to be 1.1, 1, and 0.75, respectively.
FERMENTATION-BASEL
(2023)
Proceedings Paper
Computer Science, Hardware & Architecture
Chang Wu, Hancheng Lu, Yuang Chen, Chenwu Zhang, Feihong Chen
Summary: Considering the strict delay requirements in 5G usage scenarios, existing congestion control schemes based on terminal measurement and evaluation are unable to meet the demands due to their reactive nature and lack of awareness of links. To address this, the proposal of active queue management (AQM) based buffer delay guarantee (AQM-BDG) is introduced to explicitly adjust the sending rate of the source in 5G networks. This mechanism comprehensively considers rate mismatch and buffer state in the Radio Link Control (RLC) layer, enabling timely adjustment of the sending rate by monitoring buffer dynamics. Experimental results demonstrate that AQM-BDG outperforms classical congestion control schemes by achieving high throughput and controlling queuing delay effectively.
2023 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE, WCNC
(2023)
Proceedings Paper
Computer Science, Hardware & Architecture
Qiaojia Lu, Hancheng Lu, Xinyu Yang, Feihong Chen
Summary: With limited computing capacity and heterogeneous channel conditions in Internet of Video Things (IoVT), uplink video transmission faces challenges. To address this, we propose a multi-device uplink uncoded video transmission scheme (MDUcast) that reduces computing requirements and guarantees video quality proportional to channel conditions. Optimal power allocation and subcarrier scheduling based on matching theory are employed to achieve near-optimal performance. Simulation results demonstrate that MDUcast outperforms conventional Softcast and Parcast in terms of peak signal-to-noise ratio.
2023 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE, WCNC
(2023)
Proceedings Paper
Computer Science, Hardware & Architecture
Feihong Chen, Hancheng Lu, Yazheng Wang, Chenwu Zhang
Summary: This paper investigates the signal leakage issue caused by the illegal RIS (IRIS) in a typical RIS-enhanced millimeter wave (mmWave) multiple-input multiple-output (MIMO) wiretap system. An artificial noise (AN)-based interference scheme is proposed to mitigate the security degradation caused by IRIS. Simulation results demonstrate the significant degradation of system secrecy rate (SR) caused by IRIS and validate the effectiveness of the proposed scheme in enhancing security. Furthermore, specific system factors that need to be considered when combating powerful IRIS are analyzed.
2023 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE, WCNC
(2023)
Article
Chemistry, Physical
Chia-Lin Tsai, Tung-Hsien Chan, Han-Cheng Lu, Ching-Li Huang, Kai-En Hung, Yu-Ying Lai, Yen-Ju Cheng
Summary: A new material, an angular-shaped naphthodithiophene diimide (aNDTI), was designed and synthesized. It was used as a nonvolatile polymer additive in organic photovoltaic (OPV) devices, which resulted in enhanced power conversion efficiencies of the devices.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
