Channel state information(CSI)is very important to sparse code multiple access combined with orthogonal frequency division multiplexing(SCMA-OFDM)systems for data detection.The main goal of this paper is to tackle the...Channel state information(CSI)is very important to sparse code multiple access combined with orthogonal frequency division multiplexing(SCMA-OFDM)systems for data detection.The main goal of this paper is to tackle the computational complexity and pilot overhead issues when estima-ting and tracking the channel frequency response of each user in uplink SCMA-OFDM systems.To this end,a new binary pilot structure is first designed to realize the initial channel estimation with significantly reduced computational complexity.Then,a channel tracking method is proposed to update the channel estimation in time-varying channels,which exploits a modified least mean square(LMS)technique with the feedback from the detector.Simulation results show that the pro-posed pilot structure can provide accurate channel estimation results.Moreover,the average bit error rate(BER)performance of the modified LMS algorithm can approach that of a detector with perfect CSI within 2 dB at the normalized Doppler frequency up to 6×10^(-6).展开更多
Digital content such as games,extended reality(XR),and movies has been widely and easily distributed over wireless networks.As a result,unauthorized access,copyright infringement by third parties or eavesdroppers,and ...Digital content such as games,extended reality(XR),and movies has been widely and easily distributed over wireless networks.As a result,unauthorized access,copyright infringement by third parties or eavesdroppers,and cyberattacks over these networks have become pressing concerns.Therefore,protecting copyrighted content and preventing illegal distribution in wireless communications has garnered significant attention.The Intelligent Reflecting Surface(IRS)is regarded as a promising technology for future wireless and mobile networks due to its ability to reconfigure the radio propagation environment.This study investigates the security performance of an uplink Non-Orthogonal Multiple Access(NOMA)system integrated with an IRS and employing Fountain Codes(FCs).Specifically,two users send signals to the base station at separate distances.A relay receives the signal from the nearby user first and then relays it to the base station.The IRS receives the signal from the distant user and reflects it to the relay,which then sends the reflected signal to the base station.Furthermore,a malevolent eavesdropper intercepts both user and relay communications.We construct mathematical equations for Outage Probability(OP),throughput,diversity evaluation,and Interception Probability(IP),offering quantitative insights to assess system security and performance.Additionally,OP and IP are analyzed using a Deep Neural Network(DNN)model.A deeper comprehension of the security performance of the IRS-assisted NOMA systemin signal transmission is provided by Monte Carlo simulations,which are also carried out to confirm the theoretical conclusions.展开更多
Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discon...Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discontinuous transmission (DTX)at user equipment (UE) is adopted to reduce the interferencecorrelation across different time slots. By utilizingstochastic geometry, we analytically derive themean local delay and energy efficiency (EE) of an uplinkHetNet with UE random DTX scheme under theDUDA mode. These expressions are further approximatedas closed forms under reasonable assumptions.Our results reveal that under the DUDA mode, there isan optimal EE with respect to mute probability underthe finite local delay constraint. In addition, with thesame finite mean local delay as under the coupled uplinkand downlink access (CUDA) mode, the HetNetsunder the DUDA mode can achieve a higher EE witha lower mute probability.展开更多
A novel framework of which combines smart antennas multiple antenna systems, （SA） with multiple-input multiple-output （MIMO） at the receiver, is proposed. The uplink SA-MIMO system is investigated. The joint optim...A novel framework of which combines smart antennas multiple antenna systems, （SA） with multiple-input multiple-output （MIMO） at the receiver, is proposed. The uplink SA-MIMO system is investigated. The joint optimization problem corresponding to the uplink capacity of the single-user SA-MIMO system is deduced. Then the closedform expression of the capacity is obtained in the case of equal power allocation and the same direction-of-arrivals （DOAs） from different transmit antennas at the same antenna array, and an upper bound of the capacity is also given in the case of different DOAs at the same antenna array. After that, for the general case, a suboptimal method for the capacity optimization problem is presented. Some numerical results are also given to compare the capacities of conventional MIMO and SA-MIMO systems and show that the proposed method is viable.展开更多
为了探究自适应上行功率控制(Adaptive Uplink Power Control,AUPC)在Q/V频段卫星信关站链路中的应用与优化,针对Q/V频段的高频特性,以及卫星通信面临严重的路径损耗和天气衰减的问题,特别是雨衰的影响,通过仿真对比传统AUPC、比例-积分...为了探究自适应上行功率控制(Adaptive Uplink Power Control,AUPC)在Q/V频段卫星信关站链路中的应用与优化,针对Q/V频段的高频特性,以及卫星通信面临严重的路径损耗和天气衰减的问题,特别是雨衰的影响,通过仿真对比传统AUPC、比例-积分-导数(Proportion Integral Differential,PID)控制和基于机器学习的AUPC这3种功率控制算法。结果表明,基于机器学习的AUPC算法在复杂和极端天气条件下预测表现最佳,能够有效预测链路变化并提前调整功率,保证了链路稳定性和通信质量。此外,还提出了基于多频段链路冗余和动态功率调节的优化策略,以期为高频段卫星通信系统提供重要的技术参考。展开更多
为实现密集化接入趋势下的高效接入管理和负载均衡,多无线接入点(access point, AP)协同网络架构成为一种可行的电力无线局域网协同架构。但多AP间可能存在互相干扰,触发帧竞争和碰撞会在一定程度上影响上行链路正交随机访问(uplink ort...为实现密集化接入趋势下的高效接入管理和负载均衡,多无线接入点(access point, AP)协同网络架构成为一种可行的电力无线局域网协同架构。但多AP间可能存在互相干扰,触发帧竞争和碰撞会在一定程度上影响上行链路正交随机访问(uplink orthogonal random access, UORA)的性能,并造成额外的功耗。为此,本文以降低多AP协同触发帧碰撞概率为核心,提出一种面向上行随机接入的电力无线局域网功耗优化方法,实现通信质量和系统能耗的均衡优化。首先,建立通过协同调整正交频分多址接入(orthogonal frequency division multiple access, OFDMA)的竞争窗口(competition window, CW)功耗优化模型,根据触发帧的发送成功概率揭示OCW调整和整体功耗的内在关联;其次,提出采用深度Q学习(deep Q-network, DQN)的OCW自适应动态调整算法,减少因碰撞重传造成的系统功耗。仿真实验表明,本文提出的功耗优化方法能够在确保吞吐量和延迟的同时降低整体功耗,实现电力无线局域网接入的可靠运行和控制。展开更多
Dear Editor,This letter presents a joint probabilistic scheduling and resource allocation method(PSRA) for 5G-based wireless networked control systems(WNCSs). As a control-aware optimization method, PSRA minimizes the...Dear Editor,This letter presents a joint probabilistic scheduling and resource allocation method(PSRA) for 5G-based wireless networked control systems(WNCSs). As a control-aware optimization method, PSRA minimizes the linear quadratic Gaussian(LQG) control cost of WNCSs by optimizing the activation probability of subsystems, the number of uplink repetitions, and the durations of uplink and downlink phases. Simulation results show that PSRA achieves smaller LQG control costs than existing works.展开更多
基金Supported by the National Natural Science Foundation of China(No.62171135)the Natural Science Foundation of Fujian Province(No.2023J01399)。
文摘Channel state information(CSI)is very important to sparse code multiple access combined with orthogonal frequency division multiplexing(SCMA-OFDM)systems for data detection.The main goal of this paper is to tackle the computational complexity and pilot overhead issues when estima-ting and tracking the channel frequency response of each user in uplink SCMA-OFDM systems.To this end,a new binary pilot structure is first designed to realize the initial channel estimation with significantly reduced computational complexity.Then,a channel tracking method is proposed to update the channel estimation in time-varying channels,which exploits a modified least mean square(LMS)technique with the feedback from the detector.Simulation results show that the pro-posed pilot structure can provide accurate channel estimation results.Moreover,the average bit error rate(BER)performance of the modified LMS algorithm can approach that of a detector with perfect CSI within 2 dB at the normalized Doppler frequency up to 6×10^(-6).
基金supported in part by Vietnam National Foundation for Science and Technology Development(NAFOSTED)under Grant 102.04-2021.57in part by Culture,Sports and Tourism R&D Program through the Korea Creative Content Agency grant funded by the Ministry of Culture,Sports and Tourism in 2024(Project Name:Global Talent Training Program for Copyright Management Technology in Game Contents,Project Number:RS-2024-00396709,Contribution Rate:100%).
文摘Digital content such as games,extended reality(XR),and movies has been widely and easily distributed over wireless networks.As a result,unauthorized access,copyright infringement by third parties or eavesdroppers,and cyberattacks over these networks have become pressing concerns.Therefore,protecting copyrighted content and preventing illegal distribution in wireless communications has garnered significant attention.The Intelligent Reflecting Surface(IRS)is regarded as a promising technology for future wireless and mobile networks due to its ability to reconfigure the radio propagation environment.This study investigates the security performance of an uplink Non-Orthogonal Multiple Access(NOMA)system integrated with an IRS and employing Fountain Codes(FCs).Specifically,two users send signals to the base station at separate distances.A relay receives the signal from the nearby user first and then relays it to the base station.The IRS receives the signal from the distant user and reflects it to the relay,which then sends the reflected signal to the base station.Furthermore,a malevolent eavesdropper intercepts both user and relay communications.We construct mathematical equations for Outage Probability(OP),throughput,diversity evaluation,and Interception Probability(IP),offering quantitative insights to assess system security and performance.Additionally,OP and IP are analyzed using a Deep Neural Network(DNN)model.A deeper comprehension of the security performance of the IRS-assisted NOMA systemin signal transmission is provided by Monte Carlo simulations,which are also carried out to confirm the theoretical conclusions.
基金supported in part by the National Key R&D Program of China under Grant 2021YFB 2900304the Shenzhen Science and Technology Program under Grants KQTD20190929172545139 and ZDSYS20210623091808025.
文摘Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discontinuous transmission (DTX)at user equipment (UE) is adopted to reduce the interferencecorrelation across different time slots. By utilizingstochastic geometry, we analytically derive themean local delay and energy efficiency (EE) of an uplinkHetNet with UE random DTX scheme under theDUDA mode. These expressions are further approximatedas closed forms under reasonable assumptions.Our results reveal that under the DUDA mode, there isan optimal EE with respect to mute probability underthe finite local delay constraint. In addition, with thesame finite mean local delay as under the coupled uplinkand downlink access (CUDA) mode, the HetNetsunder the DUDA mode can achieve a higher EE witha lower mute probability.
文摘第三代合作伙伴计划(3rd Generation Partnership Project,3GPP)非地面网络(non-terrestrial network,NTN)通过对5G新空口(new radio,NR)协议进行增强设计以适应卫星通信场景,可深度融合地面网络与非地面网络优势,并具备持续演进能力,是实现天地互联的关键技术方向。为应对星地传输功率与频谱资源的限制以及对广覆盖与高容量的双重需求,Rel-19 NR NTN工作组针对下行覆盖增强与上行容量/吞吐量增强两大子议题开展了标准化研究。基于此,首先概述了NTN传输的技术挑战,继而系统分析了上述议题的技术方案及标准化进展,最后展望了Rel-20 NR NTN潜在的传输增强技术演进方向。
基金The National Science and Technology Major Projects(No.2010ZX03003-002,2010ZX03003-004)the National Natural Science Foundation of China(No.60972023)+1 种基金Research Fund of National Mobile Communications Research Laboratory of Southeast University(No.2011A06)the Fund of UK-China Science Bridge
文摘A novel framework of which combines smart antennas multiple antenna systems, （SA） with multiple-input multiple-output （MIMO） at the receiver, is proposed. The uplink SA-MIMO system is investigated. The joint optimization problem corresponding to the uplink capacity of the single-user SA-MIMO system is deduced. Then the closedform expression of the capacity is obtained in the case of equal power allocation and the same direction-of-arrivals （DOAs） from different transmit antennas at the same antenna array, and an upper bound of the capacity is also given in the case of different DOAs at the same antenna array. After that, for the general case, a suboptimal method for the capacity optimization problem is presented. Some numerical results are also given to compare the capacities of conventional MIMO and SA-MIMO systems and show that the proposed method is viable.
文摘为了探究自适应上行功率控制(Adaptive Uplink Power Control,AUPC)在Q/V频段卫星信关站链路中的应用与优化,针对Q/V频段的高频特性,以及卫星通信面临严重的路径损耗和天气衰减的问题,特别是雨衰的影响,通过仿真对比传统AUPC、比例-积分-导数(Proportion Integral Differential,PID)控制和基于机器学习的AUPC这3种功率控制算法。结果表明,基于机器学习的AUPC算法在复杂和极端天气条件下预测表现最佳,能够有效预测链路变化并提前调整功率,保证了链路稳定性和通信质量。此外,还提出了基于多频段链路冗余和动态功率调节的优化策略,以期为高频段卫星通信系统提供重要的技术参考。
基金supported by the Liaoning Revitalization Talents Program(XLYC2203148)
文摘Dear Editor,This letter presents a joint probabilistic scheduling and resource allocation method(PSRA) for 5G-based wireless networked control systems(WNCSs). As a control-aware optimization method, PSRA minimizes the linear quadratic Gaussian(LQG) control cost of WNCSs by optimizing the activation probability of subsystems, the number of uplink repetitions, and the durations of uplink and downlink phases. Simulation results show that PSRA achieves smaller LQG control costs than existing works.
