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A complex-valued Vandermonde precoding technique for VLC-OFDM systems 认领 引用
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作者 WANG Zhongpeng SHEN Wengyu +1 位作者 QIU Weiwei XUE Linlin 《Optoelectronics Letters》 EI 2025年第9期541-546,共6页
High peak-to-average power ratio(PAPR)is the main disadvantage of visible light communication-based orthogonal frequency division multiplexing(VLC-OFDM)systems.To address this problem,a novel precoding method is propo... High peak-to-average power ratio(PAPR)is the main disadvantage of visible light communication-based orthogonal frequency division multiplexing(VLC-OFDM)systems.To address this problem,a novel precoding method is proposed in this paper.The complex-valued precoding matrix is constructed by a Vandermonde matrix.The researched results show the proposed precoding scheme has better PAPR performance when compared to the conventional real-valued precoding methods.Moreover,a general closed-form expression of bit error rate(BER)for Vandermonde precoded VLC-OFDM is derived for multipath fading channel.The obtained BER formula shows that Vandermonde precoding can improve the BER performance of VLC-OFDM system over multipath fading channel.This is verified by the simulation results.The researched results also show that different precoding schemes have the same BER performance but different PAPR performance. 展开更多
关键词 VLC OFDM BER Multipath fading complex valued precoding precoding method Vandermonde matrix orthogonal frequency division multiplexing vlc ofdm systemsto PAPR
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Interblock-interference-free precoding using square-root decomposition for faster-than-Nyquist signaling 认领 引用
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作者 Yan Wang Qiang Li +2 位作者 Liping Li Yingsong Li Xingwang Li 《Digital Communications and Networks》 SCIE EI CSCD 2025年第5期1493-1503,共11页
Precodings using square-root decomposition,including Cholesky and G-To-Minus-Half(GTMH)precodings,are promising for eliminating the Faster-Than-Nyquist(FTN)-induced Intersymbol-Interference(ISI).However,the existing p... Precodings using square-root decomposition,including Cholesky and G-To-Minus-Half(GTMH)precodings,are promising for eliminating the Faster-Than-Nyquist(FTN)-induced Intersymbol-Interference(ISI).However,the existing precodings using square-root decomposition either ignore Interblock-Interference(IBI)or increase the signal power,deteriorating the Bit Error Rate(BER)performance for high-order modulations and severe ISI.To overcome these drawbacks,we adopt two approaches for constructing the circular ISI matrix.The first approach inserts a Cyclic Prefix/Suffix(CPS)after each precoded symbol block,while the second approach replaces the linear convolution of the FTN shaping and the matched filter by the circular convolution,resulting in the Circular FTN(CFTN).Using these two approaches,we propose three IBI-free precodings,i.e.,CPS-Cholesky,CFTN-Cholesky and CFTN-GTMH precodings.Furthermore,employing QR decomposition shows that the GTMH and Cholesky precodings can be converted interchangeably.Thus,we demonstrate that the GTMH precoding is essentially equivalent to the Cholesky precoding.Simulation results indicate that the BER performance of three IBI-free precodings approaches Nyquist performance for moderate ISI.However,as ISI intensifies,the CPS-Cholesky scheme increases the transmit power,causing BER performance degradation.In contrast,the CFTN-Cholesky and CFTN-GTMH precodings maintain optimal BER performance even for severe ISI.Considering 128-amplitude phase shift keying with a code rate of 1/2,the BER loss of CFTN-Cholesky and CFTN-GTMH precodings for the ideal BER of 10-5 is approximately 0.002 dB and 0.005 dB when packing factor is 0.7 and roll-offfactor is 0.3.To the best knowledge of the authors,this is the optimal performance achievable through precoding. 展开更多
关键词 Faster-than-Nyquist Intersymbol-interference Interblock-interference Bit error rate Precoding
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Enhancing generalized receive spatial modulation by symbol-level precoding:Design guidelines with or without intelligent reflecting surfaces 认领 引用
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作者 Lei Zhang Miaowen Wen +2 位作者 Qiang Li Guangyuan Zheng Lixia Xiao 《Digital Communications and Networks》 SCIE EI CSCD 2025年第4期1261-1269,共9页
Existing Generalized Receive Spatial Modulation(GRSM)with Symbol-Level Precoding(SLP)forces the received signals(excluding noise)at unintended antennas to be zero,which restricts the generation of strong constructive ... Existing Generalized Receive Spatial Modulation(GRSM)with Symbol-Level Precoding(SLP)forces the received signals(excluding noise)at unintended antennas to be zero,which restricts the generation of strong constructive interference to intended receive antennas and thus limits the performance improvement over conventional GRSM with Zero-Forcing(ZF)precoding.In this paper,we propose a novel GRSM-SLP scheme that relaxes the zero receive power constraint and achieves superior performance by integrating Intelligent Reflecting Surfaces(IRSs).Specifically,our advanced GRSM-RSLP jointly exploits SLP at the transmitter and passive beamforming at the IRS to maximize the power difference between intended and unintended receive antennas,where the received signals at unintended antennas are relaxed to lie in a sphere centered at origin with a preset radius that depends on the Signal-to-Noise Ratio(SNR)value.The precoding matrix and passive beamforming vectors are optimized alternately by considering both phase shift keying and quadrature amplitude modulation signaling.It is worth emphasizing that GRSM-RSLP is a universal solution,also applicable to systems without IRS,although it performs better in IRS-assisted systems.We finally conduct extensive simulations to prove the superiority of GRSM-RSLP over GRSM-ZF and GRSM-SLP.Simulation results show that the performance of GRSM-RSLP is significantly influenced by the number of unintended antennas,and the larger the number,the better its performance.In the best-case scenario,GRSM-RSLP can achieve SNR gains of up to 10.5 dB and 12.5 dB over GRSM-SLP and GRSM-ZF,respectively. 展开更多
关键词 Receive spatial modulation Constructive interference Symbol-level precoding Intelligent reflecting surface
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A Modified Interference Exploitation 1-Bit Precoding for QAM Constellations 认领 引用
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作者 Wang Qi Zhou Wuyang 《China Communications》 SCIE EI CSCD 2025年第9期195-211,共17页
Compared to high-resolution digital-toanalog converters(DACs), deploying 1-bit DACs requires much less hardware complexity for a massive multi-user multiple-input multiple-output(MUMIMO) system. However, the feasible ... Compared to high-resolution digital-toanalog converters(DACs), deploying 1-bit DACs requires much less hardware complexity for a massive multi-user multiple-input multiple-output(MUMIMO) system. However, the feasible domain of a1-bit transmitting signal is non-continuous, and thus it is more challenging to exploit multi-user interference(MUI) by precoding. In this paper, to improve symbol decision accuracy, we investigate MUI exploitation 1-bit precoding methods for massive MU-MIMO systems under QAM modulations. Because MUIs may be constructive or destructive, we define a modified mean square error(MSE) metric for QAM constellations to jointly evaluate the effect of both MUIs and noise. Then, we model the 1-bit precoding optimization problems to minimize the sum modified MSE or the maximum modified MSE, where both the transmitting vector and receiving processing factor are optimization variables. Based on whether the receiving processing factor remains constant during the whole transmission block, two scenarios are taken into consideration. Referring to existing interference exploitation 1-bit precoding methods, we design efficient algorithms to solve the two modified MSE based problems.Compared to existing 1-bit precoding methods, our proposed methods provide better bit error rate performance, especially in more practical scenario Ⅱ(constant receiving processing factor in one block). 展开更多
关键词 constructive interference massive MU-MIMO MSE 1-bit DAC symbol-level precoding
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Lattice-reduction-aided MMSE precoding for correlated MIMO channels and performance analysis 认领 引用 被引量：2
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作者 Rui Chen Jiandong Li +1 位作者 Changle Li Wei Liu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第1期16-23,共8页
The lattice-reduction(LR)has been developed to im-prove the performance of the zero-forcing(ZF)precoder in multiple input multiple output(MIMO)systems.Under the assumptions of uncorrelated flat fading channel model an... The lattice-reduction(LR)has been developed to im-prove the performance of the zero-forcing(ZF)precoder in multiple input multiple output(MIMO)systems.Under the assumptions of uncorrelated flat fading channel model and perfect channel state information at the transmitter(CSIT),an LR-aided ZF precoder is able to collect the full transmit diversity.With the complex Lenstra-Lenstra-Lov^sz(LLL)algorithm and limited feedforward structure,an LR-aided linear minimum-mean-square-error(LMMSE)pre-coder for spatial correlated MIMO channels and imperfect CSIT is proposed to achieve lower bit error rate(BER).Assuming a time division duplexing(TDD)MIMO system,correlated block flat fad-ing channel and LMMSE uplink channel estimator,it is proved that the proposed LR-aided LMMSE precoder can also obtain the full transmit diversity through an analytical approach.Furthermore,the simulation results show that with the quadrature phase shift keying(QPSK)modulation at the transmitter,the uncoded and coded BERs of the LR-aided LMMSE precoder are lower than that of the traditional LMMSE precoder respectively when Eb-No is greater than 10 dB and 12 dB at all correlation coefficients. 展开更多
关键词 multiple input multiple output(MIMO) lattice reduction correlated channel linear precoding.
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基于RSMA的LEO卫星通信系统宽点波束调度及预编码算法 认领 引用
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作者 柴蓉 刘瑾 +1 位作者 梁承超 陈前斌 《电子学报》 EI CAS CSCD 北大核心 2026年第1期308-317,共10页
多波束低地球轨道(Low Earth Orbit,LEO)卫星通信系统因具有广覆盖、高吞吐量、低时延及部署成本低等特性而受到广泛关注。本文研究基于速率分割多址接入(Rate Splitting Multiple Access,RSMA)机制的多波束LEO卫星通信系统的用户分簇... 多波束低地球轨道(Low Earth Orbit,LEO)卫星通信系统因具有广覆盖、高吞吐量、低时延及部署成本低等特性而受到广泛关注。本文研究基于速率分割多址接入(Rate Splitting Multiple Access,RSMA)机制的多波束LEO卫星通信系统的用户分簇、混合宽点波束调度及预编码问题。综合考虑簇内及簇间相似度,提出一种基于改进均值漂移算法的用户分簇策略。首先根据用户地理位置分布及卫星点波束覆盖范围确定初始分簇结果,进而引入簇内分散度及簇间距离等指标构建成簇评估函数,并设计基于高斯核函数的调参机制,根据成簇评估结果动态调整参数,以实现簇内用户聚合性与簇间区分度的协同优化。基于所确定的用户分簇策略,进而设计一种双空间尺度资源分配策略。具体地,在较大空间尺度,研究面向多个用户簇的宽波束覆盖问题。综合考虑星间传输性能差异及用户接入性能,建模系统成本函数,将宽波束覆盖问题建模为满足约束条件的系统成本函数最小化问题。采用分支定界法求解所建模问题,通过系统性地分解搜索空间,并结合上下界剪枝策略,逐步缩小可行解范围,从而确定宽波束覆盖的用户簇集合。基于给定的宽波束覆盖策略,在较小空间尺度,设计面向单用户簇的点波束调度及预编码方案,将点波束调度及预编码问题建模为长期卫星缓存队列长度最小化问题,并将所建模问题拆分为预编码子问题及点波束调度子问题依次进行求解。针对预编码子问题,首先引入松弛变量将目标函数转换为凸函数,进而针对非凸约束条件,采用一阶泰勒展开方法对其进行转换,并将包含非线性乘积项的凸约束转换为二阶锥约束,从而得到凸优化问题,可采用工具包进行高效求解。针对点波束调度子问题,将其建模为马尔可夫决策过程,并基于近端策略优化(Proximal Policy Optimization,PPO)算法确定点波束调度策略。仿真结果验证了所提算法的有效性。 展开更多
关键词 多波束低地球轨道卫星 速率分割多址接入 用户分簇 混合宽点波束 波束调度 预编码
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基于最强径分配策略的信道混合预编码器设计 认领 引用
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作者 聂益芳 何希平 +2 位作者 唐亮贵 李余 杨军超 《计算机应用与软件》 北大核心 2026年第1期121-126,134,共6页
针对无线毫米波混合预编码系统结构,提出一种采用最强径分配策略设计信道混合预编码器的方法。该方法主要包含设计模拟预编码器和数字预编码器两个部分。依靠波束训练估计信道中主要来波路径的角度;采用最强径分配策略设计模拟预编码器... 针对无线毫米波混合预编码系统结构,提出一种采用最强径分配策略设计信道混合预编码器的方法。该方法主要包含设计模拟预编码器和数字预编码器两个部分。依靠波束训练估计信道中主要来波路径的角度;采用最强径分配策略设计模拟预编码器,让等效信道覆盖用户信道的最强来波径;根据确立的等效信道,以最大化频谱效率为目标,建立优化数学模型并求解,获得数字预编码权。理论推导和数值仿真验证了所提方案设计的有效性和合理性。相比于经典混合预编码方案,所提方案的频谱效率更优。 展开更多
关键词 无线毫米波信道 混合预编码 最强径分配 频谱效率 数学建模
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融合Gumbel-Softmax与CNN的毫米波大规模MIMO混合预编码研究 认领 引用
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作者 刘庆利 张兆庆 《电信科学》 北大核心 2026年第2期75-90,共16页
在毫米波大规模多输入多输出(multiple-input multiple-output,MIMO)系统中,自适应全连接结构存在二值约束、恒模约束以及信道信息利用不充分问题,导致频谱效率和能量效率性能受限。为此,提出一种融合Gumbel-Softmax与卷积神经网络(conv... 在毫米波大规模多输入多输出(multiple-input multiple-output,MIMO)系统中,自适应全连接结构存在二值约束、恒模约束以及信道信息利用不充分问题,导致频谱效率和能量效率性能受限。为此,提出一种融合Gumbel-Softmax与卷积神经网络(convolutional neural network,CNN)的混合预编码方法。该方法设计了两个卷积神经网络子网——发送端开关网络(transmit switching network,Ts Net)和发送端相移网络(transmit phase-shift network,TpsNet),分别用于优化开关预编码矩阵和相移预编码矩阵。在TsNet中,创新性地引入Gumbel-Softmax方法,将离散二值约束嵌入网络;TpsNet则通过相位层将输出限制在移相器有效相位区间,并借助C2层满足恒模约束。TsNet和TpsNet以并联方式构建预编码联合网络(precoding coordinated network,PCNet),通过残差网络提取毫米波信道特征。两子网并行训练,共享残差网络参数以增强特征一致性,使生成的预编码矩阵接近最优。仿真结果表明,PCNet相较于其他对比算法,频谱效率和能量效率均有显著提升。 展开更多
关键词 混合预编码 自适应全连接结构 卷积神经网络 残差网络 Gumbel-Softmax
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A Real-Time Radio Frequency Mismatch Calibration Method for Hybrid Beamforming Massive MIMO Systems 认领 引用
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作者 Tan Min Cui Mingyang +2 位作者 Zou Weixia Lei Xuemei Li Yilin 《China Communications》 SCIE EI CSCD 2026年第3期237-254,共18页
The time-division duplex(TDD)largescale antenna array system using analog-digital hybrid beamforming precoding technique has a very broad application prospect in the field of 5G/6G mobile communications.However,the ga... The time-division duplex(TDD)largescale antenna array system using analog-digital hybrid beamforming precoding technique has a very broad application prospect in the field of 5G/6G mobile communications.However,the gain imbalance between radio frequency(RF)channels introduced by RF devices leads to problems such as decreased channel estimation accuracy,deviation of precoding beam direction,and high side-lobe level.Meanwhile,the RF transceiver gain asymmetry destroys the symmetry of the uplink and downlink channels of the system,leading to a sharp performance degradation of the TDD system that employs the uplink channel information for the downlink beamforming precoding.In this paper,we propose an innovative and low-cost hardwarebased self-calibration method to solve the above two problems simultaneously.The calibration is divided into two stages:digital beamforming chain calibration(DBCC)and analog beamforming transceiver calibration(ABTC).Simulation results demonstrate that this approach simultaneously enhances the accuracy of both channel estimation and beamforming precoding,significantly improving the achievable data rate of existing precoding schemes.Furthermore,it offers considerable computational complexity advantages over current over-the-air(OTA)approaches. 展开更多
关键词 channel estimation accuracy channel reciprocity hybrid beam-forming precoding structure RF mismatch calibration TDD massive MIMO system
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Fairness-Oriented Hybrid Precoding for Massive MIMO Maritime Downlink Systems with Large-Scale CSIT 认领 引用 被引量：25
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作者 Chengxiao Liu Wei Feng +1 位作者 Te Wei Ning Ge 《China Communications》 SCIE CSCD 2018年第1期52-61,共10页
Different from conventional cellular networks, a maritime communication base station(BS) has to cover a much wider area due to the limitation of available BS sites. Accordingly the performance of users far away from t... Different from conventional cellular networks, a maritime communication base station(BS) has to cover a much wider area due to the limitation of available BS sites. Accordingly the performance of users far away from the BS is poor in general. This renders the fairness among users a challenging issue for maritime communications. In this paper, we consider a practical massive MIMO maritime BS with hybrid digital and analog precoding. Only the large-scale channel state information at the transmitter(CSIT) is considered so as to reduce the implementation complexity and overhead of the system. On this basis, we address the problem of fairness-oriented precoding design. A max-min optimization problem is formulated and solved in an iterative way. Simulation results demonstrate that the proposed scheme performs much better than conventional hybrid precoding algorithms in terms of minimum achievable rate of all the users, for the typical three-ray maritime channel model. 展开更多
关键词 maritime communication massive MIMO hybrid precoding large-scale channel state information at the transmitter(CSIT) max-min fairness
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Geometric Mean Decomposition Based Hybrid Precoding for Millimeter-Wave Massive MIMO 认领 引用 被引量：19
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作者 Tian Xie Linglong Dai +2 位作者 Xinyu Gao Muhammad Zeeshan Shakir Jianjun Li 《China Communications》 SCIE CSCD 2018年第5期229-238,共10页
Hybrid precoding can reduce the number of required radio frequency(RF)chains in millimeter-Wave(mmWave) massive MIMO systems. However, existing hybrid precoding based on singular value decomposition(SVD) requires the ... Hybrid precoding can reduce the number of required radio frequency(RF)chains in millimeter-Wave(mmWave) massive MIMO systems. However, existing hybrid precoding based on singular value decomposition(SVD) requires the complicated bit allocation to match the different signal-to-noise-ratios(SNRs) of different sub-channels. In this paper,we propose a geometric mean decomposition(GMD)-based hybrid precoding to avoid the complicated bit allocation. Specifically,we seek a pair of analog and digital precoders sufficiently close to the unconstrained fully digital GMD precoder. To achieve this, we fix the analog precoder to design the digital precoder, and vice versa. The analog precoder is designed based on the orthogonal matching pursuit(OMP) algorithm, while GMD is used to obtain the digital precoder. Simulations show that the proposed GMD-based hybrid precoding achieves better performance than the conventional SVD-based hybrid precoding with only a slight increase in complexity. 展开更多
关键词 Millimeter-wave Massive MIMO hybrid precoding geometric mean decomposition bit allocation
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Hybrid Precoding for mm Wave Massive MIMO Systems with Different Antenna Arrays 认领 引用 被引量：6
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作者 Qingfeng Ding Yuqian Deng +1 位作者 Xinpeng Gao Mengxia Liu 《China Communications》 SCIE CSCD 2019年第10期45-55,共11页
In this paper, the performance of hybrid precoding is investigated for mmWave massive MIMO systems with different antenna arrays. The hybrid precoding with partially connected architecture (PCA) is adopted. The spectr... In this paper, the performance of hybrid precoding is investigated for mmWave massive MIMO systems with different antenna arrays. The hybrid precoding with partially connected architecture (PCA) is adopted. The spectral efficiency (SE) and received energy efficiency (EE) are investigated by considering four types of antenna arrays, including uniform linear array (ULA), uniform rectangular planar array (URPA), uniform hexagonal planar array (UHPA), and uniform circular planar array (UCPA), respectively. We focus on analysis at the antenna response vector and utilize the idea of orthogonal matching pursuit algorithm to seek the optimal hybrid precoder. Furthermore, the trade-off of precoding architectures is studied between SE and received EE. Simulation results show that if the uniform planar array antenna is more concentrated, the SE and receive EE will be higher. Considering SE and received EE, the performance of planar arrays outperform linear array. There exist different optimal radio-frequency chain numbers to maximize the SE for planar array and linear array. In addition, the PCA can achieve relatively higher received EE while the SE is close to the fully connected architecture and the full digital architecture. 展开更多
关键词 massive MIMO mmWave hybrid precoding array antenna spectral efficiency
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Multi-Task Deep Learning Based Hybrid Precoding for mmWave Massive MIMO System 认领 引用 被引量：6
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作者 Zhongjie Li Wei Gao +1 位作者 Min Zhang Jiyuan Xiong 《China Communications》 SCIE EI CSCD 2021年第10期96-106,共11页
Due to the different signal-to-noise ratio(SNR)of each subchannel,the bit error rate(BER)of hybrid precoding based on singular value decomposition(SVD)decreases.In this paper,we propose a multi-task learning based pre... Due to the different signal-to-noise ratio(SNR)of each subchannel,the bit error rate(BER)of hybrid precoding based on singular value decomposition(SVD)decreases.In this paper,we propose a multi-task learning based precoding network(PN)model to solve the BER loss problem caused by SVD based hybrid precoding under imperfect channel state information(CSI).Specifically,we firstly generate a dataset including imcomplete CSI input channel matrix and corresponding output labels to train the PN model.The output labels are designed based on uniform channel decomposition(UCD)which decomposes the channel into multiple subchannels with same gain,while the vertical-bell layered space-time structure(V-BLAST)signal processing technology is combined to eliminate the inner interference of the subchannels.Then,the PN model is trained to design the analog and digital precoding/combining matrix simultaneous.Simulation results show that the proposed scheme has only negligible gap in spectrum efficiency compared with the fully digital precoding,while achieves better BER performance than SVD based hybrid precoding. 展开更多
关键词 millimeter wave massive MIMO hybrid precoding uniform channel decomposition multitask learning
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Approximate Iteration Detection and Precoding in Massive MIMO 认领 引用 被引量：6
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作者 Chuan Tang Yerong Tao +3 位作者 Yancang Chen Cang Liu Luechao Yuan Zuocheng Xing 《China Communications》 SCIE CSCD 2018年第5期183-196,共14页
Massive multiple-input multiple-output provides improved energy efficiency and spectral efficiency in 5 G. However it requires large-scale matrix computation with tremendous complexity, especially for data detection a... Massive multiple-input multiple-output provides improved energy efficiency and spectral efficiency in 5 G. However it requires large-scale matrix computation with tremendous complexity, especially for data detection and precoding. Recently, many detection and precoding methods were proposed using approximate iteration methods, which meet the demand of precision with low complexity. In this paper, we compare these approximate iteration methods in precision and complexity, and then improve these methods with iteration refinement at the cost of little complexity and no extra hardware resource. By derivation, our proposal is a combination of three approximate iteration methods in essence and provides remarkable precision improvement on desired vectors. The results show that our proposal provides 27%-83% normalized mean-squared error improvement of the detection symbol vector and precoding symbol vector. Moreover, we find the bit-error rate is mainly controlled by soft-input soft-output Viterbi decoding when using approximate iteration methods. Further, only considering the effect on soft-input soft-output Viterbi decoding, the simulation results show that using a rough estimation for the filter matrix of minimum mean square error detection to calculating log-likelihood ratio could provideenough good bit-error rate performance, especially when the ratio of base station antennas number and the users number is not too large. 展开更多
关键词 massive MIMO detection and precoding matrix inversion iteration refinement soft Viterbi decoding
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Low Complexity Joint Hybrid Precoding for Millimeter Wave MIMO Systems 认领 引用 被引量：16
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作者 Mingyang Cui Weixia Zou 《China Communications》 SCIE CSCD 2019年第2期49-58,共10页
In millimeter wave(mmWave) multiple-input multiple-output(MIMO) systems, hybrid precoding has been widely used to overcome the severe propagation loss. In order to improve the spectrum efficiency with low complexity, ... In millimeter wave(mmWave) multiple-input multiple-output(MIMO) systems, hybrid precoding has been widely used to overcome the severe propagation loss. In order to improve the spectrum efficiency with low complexity, we propose a joint hybrid precoding algorithm for single-user mmWave MIMO systems in this paper. By using the concept of equivalent channel, the proposed algorithm skillfully utilizes the idea of alternating optimization to complete the design of RF precoder and combiner. Then, the baseband precoder and combiner are computed by calculating the singular value decomposition of the equivalent channel. Simulation results demonstrate that the proposed algorithm can achieve satisfactory performance with quite low complexity. Moreover, we investigate the effects of quantization on the analog components and find that the proposed scheme is effective even with coarse quantization. 展开更多
关键词 millimeter wave MIMO 5G joint hybrid precoding low complexity
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A Precoding Scheme to Reduce the Effect of Channel Correlation for MIMO-PLC System 认领 引用 被引量：3
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作者 Wangbin Cao Hui Kang +2 位作者 Xiaolin Liang Zhiyuan Xie Xiongwen Zhao 《China Communications》 SCIE CSCD 2023年第2期216-225,共10页
MIMO technique can provide higher information throughput and transmission reliability for the PLC system.However,the MIMO-PLC system based on three-conductor cable has a high correlation among its sub-channels.Spatial... MIMO technique can provide higher information throughput and transmission reliability for the PLC system.However,the MIMO-PLC system based on three-conductor cable has a high correlation among its sub-channels.Spatial multiplexing technology will be affected by the spatial correlation between MIMO-PLC sub-channels.To reduce the system bit error rate caused by MIMO-PLC correlation among sub-channels,this paper proposed a phase rotation precoding scheme for the 2×2 closed-loop MIMO-PLC system.According to the channel transfer function of high correlation MIMO-PLC system,the phase rotation precoding matrix F is calculated,and the transmission signal matrix S is modulated with the F,the code distance at the receiving point with smallest code distance is increased by phase rotation.Simulation results show that the scheme can effectively reduce the bit error rate of the 2×2 MIMO-PLC system based on ML detection,and significantly improve the system performance. 展开更多
关键词 carrier transmission on power lines telecommunication cables error correction precoding
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Channel Correlation Based User Grouping Algorithm for Nonlinear Precoding Satellite Communication System 认领 引用 被引量：2
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作者 Ke Wang Baorui Feng +5 位作者 Jingui Zhao Wenliang Lin Zhongliang Deng Dongdong Wang Yi Cen Genan Wu 《China Communications》 SCIE CSCD 2024年第1期200-214,共15页
Low Earth Orbit(LEO)multibeam satellites will be widely used in the next generation of satellite communication systems,whose inter-beam interference will inevitably limit the performance of the whole system.Nonlinear ... Low Earth Orbit(LEO)multibeam satellites will be widely used in the next generation of satellite communication systems,whose inter-beam interference will inevitably limit the performance of the whole system.Nonlinear precoding such as Tomlinson-Harashima precoding(THP)algorithm has been proved to be a promising technology to solve this problem,which has smaller noise amplification effect compared with linear precoding.However,the similarity of different user channels(defined as channel correlation)will degrade the performance of THP algorithm.In this paper,we qualitatively analyze the inter-beam interference in the whole process of LEO satellite over a specific coverage area,and the impact of channel correlation on Signal-to-Noise Ratio(SNR)of receivers when THP is applied.One user grouping algorithm is proposed based on the analysis of channel correlation,which could decrease the number of users with high channel correlation in each precoding group,thus improve the performance of THP.Furthermore,our algorithm is designed under the premise of co-frequency deployment and orthogonal frequency division multiplexing(OFDM),which leads to more users under severe inter-beam interference compared to the existing research on geostationary orbit satellites broadcasting systems.Simulation results show that the proposed user grouping algorithm possesses higher channel capacity and better bit error rate(BER)performance in high SNR conditions relative to existing works. 展开更多
关键词 channel correlation inter-beam interference multibeam satellite Tomlinson-Harashima precoding user grouping
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Outage Probability and Achievable Rate Analysis for Massive MIMO Downlink with Mixed-DAC and MF Precoding 认领 引用 被引量：3
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作者 Qingfeng Ding Hui Shi Yichong Lian 《China Communications》 SCIE CSCD 2020年第8期95-105,共11页
This paper analyses of the outage probability and the achievable rate of massive multi-input-multi-output(MIMO) systems, in which the base station(BS) is equipped with digital-to-analog-converters(DACs) of mixed-level... This paper analyses of the outage probability and the achievable rate of massive multi-input-multi-output(MIMO) systems, in which the base station(BS) is equipped with digital-to-analog-converters(DACs) of mixed-level resolution. And the matched-filter(MF) precoding is used on the BS. Closedform expressions are derived by the distribution of user-interference power and other statistical properties in the signal-to-interference-plus-noise-ratio. Then, the combination of mixed-DACs resolution profile is chosen about outage probability and achievable rate with the BS energy consumption. And the resolution configurations between the outage probability and the achievable rate and the BS energy consumption are given. Meanwhile, Effects of related parameters and channel errors are analysed about outage probability and achievable rate. The numerical results show that the correctness of the formula derivations. As the number of users increases the system's achievable rate increases and the outage probability decreases. The selected resolution configuration system has better comprehensive performance. 展开更多
关键词 Massive MIMO mixed-DACs matched-filter precoding mixed-resolution choose outage probability and achievable rate
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Precoding Based Channel Prediction for Underwater Acoustic OFDM 认领 引用 被引量：1
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作者 CHENG En LIN Na +2 位作者 SUN Hai-xin YAN Jia-quan QI Jie 《China Ocean Engineering》 SCIE EI CSCD 2017年第2期256-260,共5页
The life duration of underwater cooperative network has been the hot topic in recent years.And the problem of node energy consuming is the key technology to maintain the energy balance among all nodes.To ensure energy... The life duration of underwater cooperative network has been the hot topic in recent years.And the problem of node energy consuming is the key technology to maintain the energy balance among all nodes.To ensure energy efficiency of some special nodes and obtain a longer lifetime of the underwater cooperative network,this paper focuses on adopting precoding strategy to preprocess the signal at the transmitter and simplify the receiver structure.Meanwhile,it takes into account the presence of Doppler shifts and long feedback transmission delay in an underwater acoustic communication system.Precoding technique is applied based on channel prediction to realize energy saving and improve system performance.Different precoding methods are compared.Simulated results and experimental results show that the proposed scheme has a better performance,and it can provide a simple receiver and realize energy saving for some special nodes in a cooperative communication. 展开更多
关键词 underwater acoustic communication precoding channel prediction CFO OFDM
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Joint Source and Relay Precoding/Beamforming Algorithm for OFDM Multi-user Cooperative Relay Systems 认领 引用 被引量：1
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作者 ZHOU Dong-yue HU Bin-jie 《Journal of Donghua University(English Edition)》 EI CAS 2014年第5期723-726,共4页
In order to reduce the feedback load of multi-user orthogonal frequency division multiplexing （ OFDM ） -based wireless systems, a practiral limited bits feedback precoding algorithm is proposed with direct source-de... In order to reduce the feedback load of multi-user orthogonal frequency division multiplexing （ OFDM ） -based wireless systems, a practiral limited bits feedback precoding algorithm is proposed with direct source-destination link based on amplify-and- forward cooperative relay network under frequency selective fading channels. Using joint minimum mean square error（MMSE） filter, the receiving decoding matrix is designed for each user in the paper. Source precoding （beamforming） matrix is optimized with convex function of weight mean square error （MSE）. Relay precoding matrix is obtained under MSE decomposition and convex optimization. The precoding matrix index is fed back for clustered subcarrier of OFDM with limited feedback. Then using interpolation algorithm, all precoding matrices are achieved at base station （BS） and relay nodes. Simulations indicate the effectiveness of the proposed limited feedback joint precoding and beam_formlng design. The proposed method can improve bit error rate （BER） performance and obtain better sum-rate performance in contrast to existing algorithms. It displays the BER performance is close to that of the unquantified precoding feedback method. 展开更多
关键词 relay multi-user precoding mean square error (MSE) feedback bits dual hop
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