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107 MHz point acquisition ultrafast 3D imaging via optical code-division multiple access 认领 引用
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作者 PENG TIAN SHUJIAN GONG +8 位作者 XIAOYIN LI YINGHUI GUO MINGBO PU QI ZHANG HEPING LIU MINGFENG XU FEI ZHANG JIANPING SHI XIANGANG LUO 《Photonics Research》 SCIE EI CAS CSCD 2026年第4期1359-1372,共14页
High-speed 3D perception in dynamic environments requires LiDAR systems with extremely high point acquisition rates(PARs).Existing methods for increasing PARs often involve complex hardware setups yet remain limited i... High-speed 3D perception in dynamic environments requires LiDAR systems with extremely high point acquisition rates(PARs).Existing methods for increasing PARs often involve complex hardware setups yet remain limited in speed,failing to meet the demands of high-dynamic-range sensing.We propose an all-optical encoded ultrafast LiDAR based on optical code-division multiple access(OCDMA).By decomposing a broadband source into 40 spectral channels via wavelength-division multiplexing(WDM)and applying six-pulse sequence encoding through fiber-delay-line-based all-optical encoding,we achieve simultaneous emission and independent decoding of all channels.Leveraging exceptional code orthogonality and the inherently narrow pulse width of all-optical encoding,a PAR of 107.6 MHz—one that surpasses all existing counterparts within the same architectural category by an order of magnitude—and a ranging accuracy of~3 mm are demonstrated.We further showcase highfidelity 3D reconstruction of static targets and dynamic imaging of a chopper,achieving a high frame rate of 10.8 kHz(83×120 points)by inter-axis rate matching of spectral-acousto-optic scanning.The system architecture offers high integration compatibility and provides a feasible technological pathway for next-generation highspeed autonomous driving and industrial vision systems. 展开更多
关键词 Dynamic Environments Point Acquisition Rate High Speed D Perception Fiber Delay Line Based Encoding Ultrafast Lidar complex hardware setups Optical Code Division Multiple Access Wavelength Division Multiplexing
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Distribution network data asset protection considering multiple topology and multi-dimensional knowledge graph 认领 引用
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作者 Junfeng Yang Li Liu +5 位作者 Nawaraj Kumar Mahato Luhan Li Jiaxuan Yang Gangjun Gong Jun Lu Chao Yang 《Global Energy Interconnection》 EI CSCD 2026年第3期585-610,共26页
The proliferation of diverse entities within distribution network has led to an increase in the scale and complexity of data asset interactions,exacerbating security risks,such as unauthorized access,data tampering,an... The proliferation of diverse entities within distribution network has led to an increase in the scale and complexity of data asset interactions,exacerbating security risks,such as unauthorized access,data tampering,and forgery.In response to these challenges,this study introduces a novel framework that enhances the protection of data assets.It incorporates a multi-dimensional knowledge graph(MDKG)to refine access control and overcome current limitations by integrating a comprehensive set of data asset attributes,roles,policies,and permissions.This approach fosters the development of a nuanced and adaptable access-control mechanism.Furthermore,the framework integrates multiple topology(MTP)for holistic security risk detection,leveraging attention mechanisms,and cross-fusion to adapt to the dynamic data security landscape.Empirical evaluations affirm the effectiveness of MDKG-based access control,whereas comparative experiments demonstrate the superiority of the MTP-based security risk model over existing models.The framework was proven to be effective in countering security risks.This study provides innovative perspectives on data asset protection and establishes a solid foundation for the advancement of smart grid technology. 展开更多
关键词 Distribution network Data asset protection Security access control Multi-dimensional knowledge graph Multiple topology Security risk detection
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URLLC Service in UAV Rate-Splitting Multiple Access: Adapting Deep Learning Techniques for Wireless Network 认领 引用
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作者 Reem Alkanhel Abuzar B.M.Adam +3 位作者 Samia Allaoua Chelloug Dina S.M.Hassan Mohammed Saleh Ali Muthanna Ammar Muthanna 《Computers, Materials & Continua》 SCIE EI 2025年第7期607-624,共18页
The 3GPP standard defines the requirements for next-generation wireless networks,with particular attention to Ultra-Reliable Low-Latency Communications(URLLC),critical for applications such as Unmanned Aerial Vehicles... The 3GPP standard defines the requirements for next-generation wireless networks,with particular attention to Ultra-Reliable Low-Latency Communications(URLLC),critical for applications such as Unmanned Aerial Vehicles(UAVs).In this context,Non-Orthogonal Multiple Access(NOMA)has emerged as a promising technique to improve spectrum efficiency and user fairness by allowing multiple users to share the same frequency resources.However,optimizing key parameters–such as beamforming,rate allocation,and UAV trajectory–presents significant challenges due to the nonconvex nature of the problem,especially under stringent URLLC constraints.This paper proposes an advanced deep learning-driven approach to address the resulting complex optimization challenges.We formulate a downlink multiuser UAV,Rate-Splitting Multiple Access(RSMA),and Multiple Input Multiple Output(MIMO)system aimed at maximizing the achievable rate under stringent constraints,including URLLC quality-of-service(QoS),power budgets,rate allocations,and UAV trajectory limitations.Due to the highly nonconvex nature of the optimization problem,we introduce a novel distributed deep reinforcement learning(DRL)framework based on dual-agent deep deterministic policy gradient(DA-DDPG).The proposed framework leverages inception-inspired and deep unfolding architectures to improve feature extraction and convergence in beamforming and rate allocation.For UAV trajectory optimization,we design a dedicated actor-critic agent using a fully connected deep neural network(DNN),further enhanced through incremental learning.Simulation results validate the effectiveness of our approach,demonstrating significant performance gains over existing methods and confirming its potential for real-time URLLC in next-generation UAV communication networks. 展开更多
关键词 Deep learning quality-of-service(QoS) rate-splitting multiple access(RSMA) unmanned aerial vehicle(UAV) ultra-reliable low-latency communication(URLLC)
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Rate-splitting multiple access-assisted ISAC design in NAFD cell-free mMIMO systems 认领 引用
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作者 Jilong Wu Fuping Si +1 位作者 Dongming Wang Pengcheng Zhu 《Digital Communications and Networks》 SCIE EI CSCD 2025年第5期1668-1678,共11页
Integrated Sensing And Communication(ISAC)is regarded as a promising technology for facilitating the rapid advancement of Sixth-Generation(6G)due to its concurrent transmission of information and environmental sensing... Integrated Sensing And Communication(ISAC)is regarded as a promising technology for facilitating the rapid advancement of Sixth-Generation(6G)due to its concurrent transmission of information and environmental sensing capabilities.Rate-Splitting Multiple Access(RSMA),through the utilization of Successive Interference Cancellation(SIC)and Rate-Splitting(RS)at the transceiver,can fulfill the sensing requirement and supersede individual radar sequence to mitigate the interference between communication and sensing.This paper investigates the transceiver design of the RSMA-assisted ISAC in a Network-Assisted Full-Duplex(NAFD)cell-free Massive Multiple-Input Multiple-Output(mMIMO)system.We first derive the expressions of the communication achievable data rate and radar sensing Signal to Interference plus Noise Ratio(SINR).Subsequently,an optimization problem is formulated to maximize the communication achievable data rate,subject to both radar sensing constraints and fronthaul constraints,an effective algorithm based on sparse beamforming scheme and Semi-Definite Relaxation(SDR)is then proposed to acquire the near-optimal transceiver.Numerical results demonstrate that the application of RSMA technology in ISAC systems can significantly enhance system performance,and reveal that Dual-Functionalities Radar-Communication(DFRC)scheme can achieve higher data rate than the traditional scheme. 展开更多
关键词 Rate-splitting multiple access Integrated sensing and communication Cell-free Network-assisted full-duplex Transceiver design
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A Comprehensive Survey on AI-Assisted Multiple Access Enablers for 6G and beyond Wireless Networks 认领 引用
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作者 Kinzah Noor Agbotiname Lucky Imoize +1 位作者 Michael Adedosu Adelabu Cheng-Chi Lee 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第11期1575-1664,共90页
The envisioned 6G wireless networks demand advanced Multiple Access (MA) schemes capable of supporting ultra-low latency, massive connectivity, high spectral efficiency, and energy efficiency (EE), especially as the c... The envisioned 6G wireless networks demand advanced Multiple Access (MA) schemes capable of supporting ultra-low latency, massive connectivity, high spectral efficiency, and energy efficiency (EE), especially as the current 5G networks have not achieved the promised 5G goals, including the projected 2000 times EE improvement over the legacy 4G Long Term Evolution (LTE) networks. This paper provides a comprehensive survey of Artificial Intelligence (AI)-enabled MA techniques, emphasizing their roles in Spectrum Sensing (SS), Dynamic Resource Allocation (DRA), user scheduling, interference mitigation, and protocol adaptation. In particular, we systematically analyze the progression of traditional and modern MA schemes, from Orthogonal Multiple Access (OMA)-based approaches like Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) to advanced Non-Orthogonal Multiple Access (NOMA) methods, including power domain-NOMA, Sparse Code Multiple Access (SCMA), and Rate Splitting Multiple Access (RSMA). The study further categorizes AI techniques—such as Machine Learning (ML), Deep Learning (DL), Reinforcement Learning (RL), Federated Learning (FL), and Explainable AI (XAI)—and maps them to practical challenges in Dynamic Spectrum Management (DSM), protocol optimization, and real-time distributed decision-making. Optimization strategies, including metaheuristics and multi-agent learning frameworks, are reviewed to illustrate the potential of AI in enhancing energy efficiency, system responsiveness, and cross-layer RA. Additionally, the review addresses security, privacy, and trust concerns, highlighting solutions like privacy-preserving ML, FL, and XAI in 6G and beyond. By identifying research gaps, challenges, and future directions, this work offers a structured resource for researchers and practitioners aiming to integrate AI into 6G MA systems for intelligent, scalable, and secure wireless communications. 展开更多
关键词 Sixth Generation(6G) Artificial Intelligence(AI) Multiple Access(MA) Machine Learning(ML) NonOrthogonal Multiple Access(NOMA) Reconfigurable Intelligent Surfaces(RIS) semantic communications Integrated Sensing and Communication(ISAC) spectrum management optimization techniques security and privacy
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Rate Splitting Multiple Access Based Integrated Sensing and Communication with Reconfigurable Holographic Surface 认领 引用
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作者 Li Yuwei Zhou Xiaotian +2 位作者 Zhang Haixia Yuan Dongfeng Lin Wei 《China Communications》 SCIE EI CSCD 2025年第12期240-254,共15页
In this paper,we propose a rate splitting multiple access(RSMA)based integrated sensing and communication system(ISAC),where the sensing and communication are realized simultaneously with the RSMA signal.Further,recon... In this paper,we propose a rate splitting multiple access(RSMA)based integrated sensing and communication system(ISAC),where the sensing and communication are realized simultaneously with the RSMA signal.Further,reconfigurable holographic surface(RHS)is utilized to replace the traditional antennas for beam generation,expecting to combine the advantages of RSMA and RHS.To maximize the weighted summation of system rate and probing power,an optimization problem is formulated to jointly design the digital beamformer,the holographic beamformer and the message splitting vectors.To solve the non-convex problem,we first decompose it into two subproblems,where one jointly designs the digital beamformer and message splitting vectors,and the other deals with the holographic beamformer.An iterative algorithm,which leverages successive convex approximation and semi-definite relaxation,is proposed to achieve the sub-optimal solution through solving these two subproblems alternatively.Simulations confirm the effectiveness and efficiency of the proposed algorithm. 展开更多
关键词 integrated sensing and communication rate splitting multiple access reconfigurable holographic surface
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Indoor localization with channel state information images from selected multiple access points 认领 引用
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作者 LONG Liang WANG Xiaopeng +1 位作者 WANG Jiang LI Gang 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2025年第4期569-577,共9页
To improve the accuracy of indoor localization methods with channel state information(CSI)images,a localization method that used CSI images from selected multiple access points(APs)was proposed.The method had an off-l... To improve the accuracy of indoor localization methods with channel state information(CSI)images,a localization method that used CSI images from selected multiple access points(APs)was proposed.The method had an off-line phase and an on-line phase.In the off-line phase,three APs were selected from the four APs in the localization area based on the received signal strength indication(RSSI).Next,CSI data was collected from the three selected APs using a commercial Intel 5300 network interface card.A single-channel subimage was constructed for each selected AP by combining the amplitude information from different antennas and the phase difference information between neighboring antennas.These sub-images were then merged to form a three-channel RGB image,which was subsequently fed into the convolutional neural network(CNN)for training.The CNN model was saved upon completion of training.In the on-line phase,the CSI data from the target device was collected,converted into images using the same process as in the off-line phase,and fed into the well-trained CNN model.Finally,the real position of the target device was estimated using a weighted centroid algorithm based on the model’s output probabilities.The proposed method was validated in indoor environments using two datasets,achieving good localization accuracy. 展开更多
关键词 WiFi indoor localization multiple access points channel state information image convolutional neural network(CNN) fingerprint localization weighted centroid algorithm
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Non-Orthogonal Multiple Access in Cell-Free Massive MIMO Networks 认领 引用 被引量：9
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作者 Yao Zhang Haotong Cao +1 位作者 Meng Zhou Longxiang Yang 《China Communications》 SCIE CSCD 2020年第8期81-94,共14页
In this paper, we investigate the downlink performance of cell-free massive multi-input multi-output non-orthogonal multiple access(CF-m MIMO-NOMA) system with conjugate beamforming precoder and compare against the or... In this paper, we investigate the downlink performance of cell-free massive multi-input multi-output non-orthogonal multiple access(CF-m MIMO-NOMA) system with conjugate beamforming precoder and compare against the orthogonal multiple access(OMA) counterpart. A novel achievable closed-form spectral efficiency(SE) expression is derived, which characterizes the effects of the channel estimation error, pilot contamination, imperfect successive interference cancellation(SIC) operation, and power optimization technique. Then, motivated by the closedform result, a sum-SE maximization algorithm with the sequential convex approximation(SCA) is proposed, subject to each AP power constraint and SIC power constraint. Numerical experiments indicate that the proposed sum-SE maximization algorithms have a fast converge rate, within about five iterations. In addition, compared with the full power control(FPC) scheme, our algorithms can significantly improve the achievable sum-SE. Moreover, NOMA outperforms OMA in many respects in the presence of the proposed algorithms. 展开更多
关键词 non-orthogonal multiple access CF-mMIMO successive interference cancellation power optimization sequential convex approximation
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Uplink Grant-Free Pattern Division Multiple Access (GF-PDMA) for 5G Radio Access 认领 引用 被引量：11
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作者 Wanwei Tang Shaoli Kang +1 位作者 Bin Ren Xinwei Yue 《China Communications》 SCIE CSCD 2018年第4期153-163,共11页
Massive machine type communication(m MTC) is one of the key application scenarios for the fifth generation mobile communication(5 G). Grant-free(GF) transmission can reduce the high signaling overhead in m MTC. Non-or... Massive machine type communication(m MTC) is one of the key application scenarios for the fifth generation mobile communication(5 G). Grant-free(GF) transmission can reduce the high signaling overhead in m MTC. Non-orthogonal multiple access(NMA) can support more users for m MTC than orthogonal frequency division multiple access(OFDMA). Applying GF transmission in NMA system becomes an active topic recently. The in-depth study on applying GF transmission in pattern division multiple access(PDMA), a competitive candidate scheme of NMA, is investigated in this paper. The definition, latency and allocation of resource and transmission mechanism for GF-PDMA are discussed in detail. The link-level and system-level evaluations are provided to verify the analysis. The analysis and simulation results demonstrate that the proposed GF-PDMA has lower latency than grant based PDMA(GB-PDMA), possesses strong scalability to confront collision and provides almost 2.15 times gain over GF-OFDMA in terms of supporting the number of active users in the system. 展开更多
关键词 pattern division multiple access（PDMA） grant-free uplink massive machinetype communication （mMTC） 5G
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Outage Performance of Non-Orthogonal Multiple Access Based Unmanned Aerial Vehicles Satellite Networks 认领 引用 被引量：19
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作者 Ting Qi Wei Feng Youzheng Wang 《China Communications》 SCIE CSCD 2018年第5期1-8,共8页
With rapid development of unmanned aerial vehicles(UAVs), more and more UAVs access satellite networks for data transmission. To improve the spectral efficiency, non-orthogonal multiple access(NOMA) is adopted to inte... With rapid development of unmanned aerial vehicles(UAVs), more and more UAVs access satellite networks for data transmission. To improve the spectral efficiency, non-orthogonal multiple access(NOMA) is adopted to integrate UAVs into the satellite network, where multiple satellites cooperatively serve the UAVs and mobile terminal using the Ku-band and above. Taking into account the rain fading and the fading correlation, the outage performance is first analytically obtained for fixed power allocation and then efficiently calculated by the proposed power allocation algorithm to guarantee the user fairness. Simulation results verify the outage performance analysis and show the performance improvement of the proposed power allocation scheme. 展开更多
关键词 non-orthogonal multiple access（NOMA） outage performance power allocation satellite networks unmanned aerial vehicles （UAVs）
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Design Framework of Unsourced Multiple Access for 6G Massive IoT 认领 引用 被引量：3
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作者 Chunlin Yan Siying Lyu +2 位作者 Sen Wang Yuhong Huang Xiaodong Xu 《China Communications》 SCIE CSCD 2024年第1期1-12,共12页
In this paper,ambient IoT is used as a typical use case of massive connections for the sixth generation(6G)mobile communications where we derive the performance requirements to facilitate the evaluation of technical s... In this paper,ambient IoT is used as a typical use case of massive connections for the sixth generation(6G)mobile communications where we derive the performance requirements to facilitate the evaluation of technical solutions.A rather complete design of unsourced multiple access is proposed in which two key parts:a compressed sensing module for active user detection,and a sparse interleaver-division multiple access(SIDMA)module are simulated side by side on a same platform at balanced signal to noise ratio(SNR)operating points.With a proper combination of compressed sensing matrix,a convolutional encoder,receiver algorithms,the simulated performance results appear superior to the state-of-the-art benchmark,yet with relatively less complicated processing. 展开更多
关键词 channel coding compressed sensing massive Internet-of-Things(IoT) sparse interleaverdivision multiple access(SIDMA) the sixth generation(6G)mobile communications unsourced multiple access
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Max-Min Fair RIS-Aided Rate-Splitting Multiple Access for Multigroup Multicast Communications 认领 引用 被引量：5
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作者 Tiantian Li Haixia Zhang +1 位作者 Shuaishuai Guo Dongfeng Yuan 《China Communications》 SCIE CSCD 2023年第1期184-198,共15页
Rate-splitting multiple access(RSMA)can cope with a wide range of propagation conditions in multigroup multicast communications through rate splitting optimization.To breakthrough the grouprate limited bottleneck,reco... Rate-splitting multiple access(RSMA)can cope with a wide range of propagation conditions in multigroup multicast communications through rate splitting optimization.To breakthrough the grouprate limited bottleneck,reconfigurable intelligent surface(RIS)technique can be introduced to assist wireless communications through enhancing the channel quality.In RIS-aided RSMA multigroup multicasting,how to provide fair and high-quality multiuser service under power and spectrum constraints is essential.In this paper,we propose a max-min fair RIS-aided rate-splitting multiple access(MMF-RISRSMA)scheme for multigroup multicast communications,where the rate fairness is obtained by maximizing the minimum group-rate.In doing so,we jointly optimize the beamformers,the rate splitting vector at the transmitter,as well as the phase shifts at RIS.To solve it,we divide the original optimization problem into two subproblems and alternately optimize the variables.The beamforming and rate splitting optimization subproblem is solved by using the successive convex approximation technique.The phase shift optimization subproblem is solved through the penalty function method to achieve a rank-one locally optimal solution.Simulations demonstrate that the proposed MMF-RIS-RSMA scheme can obtain significant performance gain in terms of the minimum group-rate. 展开更多
关键词 multigroup multicast communications rate-splitting multiple access(RSMA) reconfigurable intelligent surfaces(RIS) max-min fairness(MMF)
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Resource Allocation Based on User Pairing and Subcarrier Matching for Downlink Non-Orthogonal Multiple Access Networks 认领 引用 被引量：2
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作者 Zhixin Liu Changjian Liang +2 位作者 Yazhou Yuan Kit Yan Chan Xinping Guan 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2021年第3期679-689,共11页
The traditional orthogonal multiple access(OMA)is unable to satisfy the needs of large number of smart devices.To increase the transmission rate in the limited spectrum resource,implementation of both non-orthogonal m... The traditional orthogonal multiple access(OMA)is unable to satisfy the needs of large number of smart devices.To increase the transmission rate in the limited spectrum resource,implementation of both non-orthogonal multiple access(NOMA)and successive interference cancelation(SIC)is essential.In this paper,an optimal resource allocation algorithm in NOMA is proposed to maximize the total system rate in a multi-sector multi-subcarrier relay-assisted communication network.Since the original problem is a non-convex problem with mixed integer programming which is non-deterministic polynomial-time(NP)-hard,a three-step solution is proposed to solve the primal problem.Firstly,we determine the optimal power allocation of the outer users by using the approach of monotonic discrimination,and then the optimal user pairing is determined.Secondly,the successive convex approximation(SCA)method is introduced to transform the non-convex problem involving central users into convex one,and the Lagrangian dual method is used to determine the optimal solution.Finally,the standard Hungarian algorithm is utilized to determine the optimal subcarrier matching.The simulation results show that resource allocation algorithm is able to meet the user performance requirements with NOMA,and the total system rate is improved compared to the existing algorithms. 展开更多
关键词 Non-orthogonal multiple access(NOMA) power control rate maximization subcarrier matching user pairing
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Minimizing the Impact of Long Propagation Delay on Multiple Access for Wireless Networks 认领 引用 被引量：1
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作者 刘凯 李亚燕 王新 《China Communications》 SCIE CSCD 2011年第7期21-33,共13页
A multiple access protocol is proposed to greatly improve multiple access performance of wireless networks with long propagation delay. All the nodes with packets to send can make rapid successful reservation in acces... A multiple access protocol is proposed to greatly improve multiple access performance of wireless networks with long propagation delay. All the nodes with packets to send can make rapid successful reservation in access reservation mini-slots, which is adaptively adjusted according to current traffic load and idle channel resources. A Central Control Node (CCN) coordinates channel reservation and allocates on-demand channel resources to the successfully accessed nodes on two channels. Each node can employ only one handshake to accomplish each communication session, and transmit one or multiple data packets piggybacked with acknowledgment (ACK) information to one or multiple destination nodes in each frame until the end of their communication sessions, which greatly minimizes the impact of long propagation delay caused by handshakes and improves channel efficiency. Simulation results show that the proposed protocol obviously outperforms the Centralized Scheduling-based Medium Access Control (CSMAC) protocol, especially in the presence of long propagation delay. 展开更多
关键词 wireless networks multiple access on-demand reservation conflict-free transmission long propagation delay
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The Extended Hybrid Carrier-Based Multiple Access Technology for High Mobility Scenarios 认领 引用 被引量：2
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作者 Ge Song Xiaojie Fang Xuejun Sha 《China Communications》 SCIE CSCD 2024年第1期53-68,共16页
The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering attention.In this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless communicatio... The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering attention.In this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless communication.By employing the EHC modulation,a power layered multiplexing framework is realized,which exhibits enhanced interference suppression capability owing to the more uniform energy distribution design.The implementation method and advantage mechanism are explicated respectively for the uplink and downlink,and the performance analysis under varying channel conditions is provided.In addition,considering the connectivity demand,we explore the non-orthogonal multiple access(NOMA)method of the EHC system and develop the EHC sparse code multiple access scheme.The proposed scheme melds the energy spread superiority of EHC with the access capacity of NOMA,facilitating superior support for massive connectivity in high mobility environments.Simulation results have verified the feasibility and advantages of the proposed scheme.Compared with existing HC multiple access schemes,the proposed scheme exhibits robust bit error rate performance and can better guarantee multiple access performance in complex scenarios of nextgeneration communications. 展开更多
关键词 extended hybrid carrier system high mo-Received:Jun.09,2023 Revised:Nov.20,2023 Editor:Yuanwei Liu bility communications multiple access
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Space-division multiple access for CDMA multiuser underwater acoustic communications 认领 引用 被引量：2
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作者 Jingwei Yin Pengyu Du +1 位作者 Guang Yang Huanling Zhou 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2015年第6期1184-1190,共7页
Time reversal mirror （TRM） can use the physical characteristics of the underwater acoustic （UWA） channel to focus on the desired user in multi-user UWA communication. The active average sound intensity （AASI） de... Time reversal mirror （TRM） can use the physical characteristics of the underwater acoustic （UWA） channel to focus on the desired user in multi-user UWA communication. The active average sound intensity （AASI） detector can estimate all azimuths of users with the same frequency band at the same time in order to achieve directional communication by vector combination. Space-division multiple access （SDMA） based on TRM combined with the AASI detector is proposed in this paper, which can make the capacity of the code division multiple access （CDMA） UWA system significantly increase. The simulation and lake test results show that the 7-user UWA multi-user system can achieve low bit error communication. 展开更多
关键词 underwater acoustic （UWA） communication space-division multiple access （SDMA） time reversal mirror （TRM） active average sound intensity （AASI） detector.
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Joint Non-Orthogonal Multiple Access (NOMA) & Walsh-Hadamard Transform: Enhancing the Receiver Performance 认领 引用 被引量：2
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作者 Muhammad Rehan Usman Arsla Khan +1 位作者 Muhammad Arslan Usman Soo young Shin 《China Communications》 SCIE CSCD 2018年第9期160-177,共18页
Non-orthogonal multiple access(NOMA) is a new access method to achieve high performance gains in terms of capacity and throughput, so it is currently under consideration as one of the candidates for fifth generation(5... Non-orthogonal multiple access(NOMA) is a new access method to achieve high performance gains in terms of capacity and throughput, so it is currently under consideration as one of the candidates for fifth generation(5 G) technologies. NOMA utilizes power domain in order to superimpose signals of multiple users in a single transmitted signal. This creates a lot of interference at the receive side. Although the use of successive interference cancellation(SIC) technique reduces the interference, but to further improve the receiver performance, in this paper, we have proposed a joint Walsh-Hadamard transform(WHT) and NOMA approach for achieving better performance gains than the conventional NOMA. WHT is a well-known code used in communication systems and is used as an orthogonal variable spreading factor(OVSF) in communication systems. Application of WHT to NOMA results in low bit error rate(BER) and high throughput performance for both low and high channel gain users. Further, it also reduces peak to average power ratio(PAPR) of the user signal. The results are discussed in terms of comparison between the conventionalNOMA and the proposed technique, which shows that it offers high performance gains in terms of low BER at different SNR levels, reduced PAPR, high user throughput performance and better spectral efficiency. 展开更多
关键词 Bit error rate （BER） non-orthogonal multiple access （NOMA） orthogonal frequency division multiplexing （OFDM） peak to average power ratio （PAPR） successive interference cancellation （SIC） throughput and Walsh-Hadamard transform （WHT）.
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New acquisition decision algorithm for multiple access interference suppression in DSSS system 认领 引用 被引量：1
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作者 Yongqing Wang Siliang Wu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第1期157-163,共7页
For decreasing the multiple access interference of weaker signal acquisition in direct sequence spread spectrum(DSSS)systems,a new single decision algorithm is presented.The maximum value of correlation results is con... For decreasing the multiple access interference of weaker signal acquisition in direct sequence spread spectrum(DSSS)systems,a new single decision algorithm is presented.The maximum value of correlation results is conventionally detected.However,there may be not only one strong peak among correlation results when the cross-correlation noise is strong enough to affect the correlation results.The proposed algorithm decreases the false alarm probability through the decision of the ratio of the maximum value and the second maximum value of the correlation results.Theoretical analysis and simulation results indicate that the proposed algorithm effectively suppresses the acquisition problem of multiple access interference in DSSS system. 展开更多
关键词 direct sequence spread spectrum(DSSS) multiple access interference acquisition false alarm probability
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Optimal UAV deployment in downlink non-orthogonal multiple access system:a two-user case 认领 引用
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作者 Liu Tingting Wang Yuntian +2 位作者 Wang Junhua Pan Ziyu Yu Yu 《High Technology Letters》 EI CAS 2020年第4期411-416,共6页
This paper investigates a unmanned aerial vehicle(UAV)deployment problem in a non-orthogonal multiple access(NOMA)system,where the UAV is deployed as an aerial mobile base station to transmit data to two ground users.... This paper investigates a unmanned aerial vehicle(UAV)deployment problem in a non-orthogonal multiple access(NOMA)system,where the UAV is deployed as an aerial mobile base station to transmit data to two ground users.An optimization problem is formulated by deploying the UAV for maximizing the sum rate of the two users.In order to solve the optimization problem,the feasible solution region is first reduced to a line segment between two users.Then,the optimization problem is simplified to a univariate problem,which can be solved by derivation under a certain situation,and the corresponding analytical solution is also provided.Moreover,a generalized algorithm,which considers 2 situations,is proposed to further determine the optimal UAV’s location.Specifically,four cases are discussed in the first situation.Extensive simulations are depicted to demonstrate effectiveness of the proposed algorithm and its superiority over the benchmarks in maximizing the two users’sum rate. 展开更多
关键词 unmanned aerial vehicle(UAV)deployment downlink non-orthogonal multiple access(NOMA) two-user case
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A multiple copyright identification watermarking algorithm based on code division multiple access 认领 引用
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作者 张帆 li Jie +1 位作者 Su Yuting Zhang Chuntian 《High Technology Letters》 EI CAS 2008年第4期377-383,共7页
A multiple watermarking algorithm is presented according to the multiple accessing technique of the code division multiple access （CDMA） system. Multiple watermarks are embedded into digital images in the wavelet tr... A multiple watermarking algorithm is presented according to the multiple accessing technique of the code division multiple access （CDMA） system. Multiple watermarks are embedded into digital images in the wavelet transform domain. Each of the watermarks is embedded and extracted independently without impacts to each other. Multiple watermarks are convolution encoded and block interleaved, and the orthogonal Gold sequences are used to spread spectrum of the copyright messages. CDMA encoded water-mark messages are embedded into the wavelet sub-bands excluding the wavelet HH1 sub-bands. The embedment amplitude is decided by Watson＇ s perceptual model of wavelet transform domain, and the embedmeut position in the selected wavelet sub-bands is decided randomly by a pseudo-random noise （PN） sequence. As a blind watermm＇king algorithm, watermarks are extracted without original image. The watermarking capacity of proposed algorithm is also discussed. When two watermarks are embedded in an image at the same time, the capacity is larger than the capacity when a single watermark is embedded, and is smaller than the sum of the capacity of two separately embedded watermarks. Experimental results show that the proposed algorithm improves the detection bits error rate （BER） observably, and the multiple watermarks have a preferable robustness and invisibility. 展开更多
关键词 code division multiple access （CDMA） watermarking convolutional coding
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