一种通用宽带MIMO信道模型

针对宽带的MIMO信道建模问题,提出一种通用多天线信道模型及其构造方法.该方法把克罗内克积应用到频域,同时提出频域散射衰落加权因子的概念,由此导出一种室外宽带MIMO散射分布模型.经过简化,该模型还可以应用到室内场景.仿真结果表明,这种通用信道模型能够准确的描述出宽带MIMO信道的视距(LoS)、非视距(NLoS)、室内外散射特征以及孔径效应.     

宽带车辆到车辆MIMO通信系统性能研究

基于二维（Two-Dimensional,2D）双环和三维（Three-Dimensional,3D）双圆柱体散射模型,在视距（Line-of-Sight,LOS）和非视距（Non-Line-of-Sight,NLOS）场景下,利用宽带2D和3D几何散射模型开展信道仿真,基于实现的MIMO信道矩阵,结合空-频区块编码（Space-Frequency Block Coding,SFBC）和正交频分复用（Orthogonal Frequency Division Multiplexing,OFDM）技术,研究了收发终端的移动速度、天线阵元间隔等对宽带车辆到车辆（Vehicle-to-Vehicle,V2V）多输入多输出（Multiple-Input Multiple-Output,MIMO）通信系统误码率（Bit Error Rate,BER）和信道容量的影响.结果表明:随着收发终端移动速度增大,信号衰减加快,宽带MIMO V2V通信系统的BER增大;随着收发端天线阵元间隔的增大,MIMO信道的相关性减小,通信系统的BER减小,MIMO信道的信道容量增大.文中研究方法和结论将对V2V MIMO系统性能分析有一定的指导意义.     

分布式多入多出正交频分复用快衰落感知估计

针对分布式多输入多输出正交频分复用(MIMO-OFDM)快衰落系统,为了消除快衰落信道的干扰,提出一种分布式MIMO-OFDM系统快衰落信道估计方法.该方法利用分布式快衰落信道间的感知信息在空间、时延和多普勒频移上具有的互相关性,求取三维互相关联合稀疏信道模型.推导预相关随机导频测量矩阵,结合分布式压缩感知算法,以能量有效的方式,对快衰落稀疏信道参数进行联合压缩测量和重构,得到各分布式MIMO接收端任意的稀疏信道系数.理论分析与仿真结果都表明,该方法与传统的信道估计方法相比,可以明显提高系统频谱效率和误码率,减少计算复杂度.     

一种基于无人机MIMO信道的容量分析方法

针对无人机通信环境特点以及多天线系统(Multi-Input Multi-Output,MIMO),建立了具有直射、反射以及散射分量的无人机MIMO三维GBSBCM信道模型,给出了无人机空时频信道相关函数的简要形式;采用信道矩阵分解、信道系数归一化的方法,推导了无人机的MIMO信道相关矩阵的计算方法;根据信道相关矩阵中参数定量分析法,仿真分析了在发射端信道未知条件下的多天线间隔对无人机MIMO信道容量的影响。通过容量的影响分析,对无人机MIMO天线间隔的合理配置具有一定的理论参考价值和实际应用价值。     

多径信道下MIMO系统发送天线数估计

为了解决认知无线电或信号截获中多径信道下MIMO系统发送天线数估计问题,首先分析了现有模型在多径信道下失效的原因,将MIMO多径信道模型等效变换出一种虚拟信道矩阵,从而建立多径信道下MIMO系统发送天线数估计模型;然后,利用随机矩阵理论中协方差矩阵最小特征值分布的相关研究结果,证明了时不变瑞利信道的协方差矩阵最小特征值收敛于第二类Tracy-Widom分布,分析了该特点对发送天线数估计的影响,并提出一种改进的RMT估计算法来估计多径信道下MIMO系统发送天线数.最后对改进算法进行了仿真验证,结果表明在低信噪比和小数据条件下,改进算法的估计性能相比RMT算法有较大提升.     

光多输入多输出技术研究进展

介绍了光多输入多输出(MIMO)系统模型及其特点,分析讨论了光纤MIMO和自由空间光MIMO两种模型的信道矩阵及相关的编码技术和检测技术,指出当前光MIMO技术存在的一些问题,并对以后的研究作了进一步的探讨.     

一种分布式多入多出(MIMO)信道的容量研究

分布式MIMO系统结合了点对点MIMO信道与分布式天线系统两者的特点，能改善链路的质量，提高覆盖面积。本文提出了一种包含路径损耗、阴影衰落与小尺度衰落的分布式MIMO信道模型，分析推导了采用该模型时的分布式MIMO信道容量。通过计算机仿真，研究分析了阴影衰落、Rice信道因子K等因素对分布式MIMO上行信道容量的影响，得出了分布式MIMO信道容量空间分布的特点。     

LOS环境下散射体对MIMO信道特性的影响

针对室外视距(LOS)传输情况下的MIMO信道,结合电磁散射分析研究了典型散射体对MIMO信道性能的影响.该模型考虑了实践中常用的微带天线,并推导出在传输路径外存在圆柱电磁散射体条件下MIMO信道矩阵的解析公式,应用该公式分析了MIMO信道容量和矩阵条件数等特征参量.仿真结果表明,该模型能够描述出不同参数下信道特性的变化,对实际MIMO系统的设计有一定的参考意义.     

分布式MIMO雷达目标散射模型研究

针对当前分布式多输入多输出(MIMO)雷达目标散射模型的不足,提出了一种三维特体目标模型;在考虑点散射体电磁散射的方向性、遮蔽及收发天线方位角、俯仰角等因素的条件下,推导了目标静态雷达截面积(RCS)的计算公式和MIMO雷达信道的相关函数;同时,仿真分析了目标动态RCS的统计模型及其与收发天线双基地角的关系,以及MIMO雷达信道空间去相关的条件。仿真分析结果与RCS的经典统计模型、双基地RCS的经验结论以及单基地雷达回波信号去相关角度的经验值是吻合的,证实了模型的科学性和合理性。研究结果对分布式MIMO雷达的检测、跟踪和系统配置等研究具有参考价值。     

一种新的MIMO信道模型

实际无线通信环境中发送天线之间以及接收天线之间存在相关性.针对以上特点,从多径MIMO信道的特性出发,首先建立发射天线相关系数矩阵和接收天线相关系数矩阵,并将它们引入无线信道的莱斯MIMO信道模型中.最后通过分析LOS MIMO信道相关模型和瑞利衰落MIMO信道相关模型,给出了具体的建模步骤.仿真结果表明采用本文方法产生的信道模型的MIMO系统误码率更低,从而验证了该信道模型能够较好地模拟MIMO系统的空间信道.     

A novel wideband space‐time channel simulator based on the geometrical one‐ring model with applications in MIMO‐OFDM systems

In this paper, we extend the geometrical one‐ring multiple‐input multiple‐output (MIMO) channel model with respect to frequency selectivity. Our approach enables the design of efficient and accurate simulation models for wideband space‐time MIMO channels under isotropic scattering conditions. Two methods will be provided to compute the parameters of the simulation model. Especially, the temporal, frequency and spatial correlation properties of the proposed wideband space‐time MIMO channel simulator are studied analytically. It is shown that any given specified or measured discrete power delay profile (PDP) can be incorporated into the simulation model. The high accuracy of the simulation model is demonstrated by comparing its statistical properties with those of the underlying reference model with specified correlation properties in the time, frequency and spatial domain. As an application example of the new MIMO frequency‐selective fading channel model, we study the influence of various channel model parameters on the system performance of a space‐time coded orthogonal frequency division multiplexing (OFDM) system. For example, we investigate the influence of the antenna element spacings of the base station (BS) antenna as well as the mobile station (MS) antenna. It turns out that an increasing of the antenna element spacing at the BS side results in a higher diversity gain than an increasing of the antenna element spacing at the MS side. Furthermore, the diversity gain brought in by space‐time block coding schemes is investigated by simulation. Our results show that transmitter diversity can significantly reduce the symbol error rate (SER) of multiple antenna systems. Finally, the influence of the Doppler effect and the impact of imperfect channel state information (CSI) on the system performance is also investigated. Copyright © 2009 John Wiley & Sons, Ltd.     

圆筒散射的无人机MIMO信道模型研究

针对无人机环境特点和多天线系统,建立了基于圆筒散射的三维几何无人机MIMO宽带信道模型。该模型不仅由直射、反射和散射等多种分量组成,还考虑了飞行参数、散射环境以及天线间距等因素。根据地面控制站方位角非全向散射和俯仰角非对称分布的特点,结合无人机实际飞行参数特点,推导出简洁的闭环空时频联合相关函数,并通过仿真进行了有效性和可行性验证。     

Study on the dual-orthogonal polarized MIMO wideband satellite mobile channel based on a 4-state LMS model

This paper focused on establishing a MIMO wideband land mobile satellite (LMS) channel statistics model. The particularity of this channel modeling was its wideband characteristics and the DPAs structure. Based on the Loo and Fontan model, a 4-state wideband LMS model was analyzed by combination of a Markov chain and properties of the wideband channel including its multipath excess delay and temporal-correlation performance. The paper also studied the effects of DPAs on channel modeling including the Cross Polarization Discrimination (XPD) and Cross Polarization Coupling (XPC). Through detailed analysis of the 4-state widebandLMSmodel and the effects of DPAs on channel modeling above, a typical dual-orthogonal polarized MIMO wideband satellite mobile channel model could be built. According to the modeling steps, channel time-series can be generated to assist further analysis of the system performance and evaluation of new technologies.     

Wideband HAP-MIMO Channels: A 3-D Modeling and Simulation Approach

High-altitude platforms (HAPs) are considered as an alternative technology to provide future generation broadband wireless communications services. This paper proposes a three-dimensional (3-D) geometry-based reference model for wideband HAP multiple-input–multiple-output (MIMO) channels. The statistical properties of the channel are analytically studied in terms of the elevation angle of the platform, the antenna arrays configuration, and the angular, the Doppler and the delay spread. Specifically, the space-time-frequency correlation function (STFCF), the space-Doppler power spectrum, and the power space-delay spectrum are derived for a 3-D non-isotropic scattering environment. Finally, a sum-of-sinusoids statistical simulation model for wideband HAP-MIMO channels is proposed. The results show that the simulation model accurately and efficiently reproduces the STFCF of the reference model. The proposed models provide a convenient framework for the characterization, analysis, test, and design of wideband HAP-MIMO communications systems with line-of-sight and non-line-of-sight links.     

一种基于随机散射簇的非平稳3D空间信道模型

针对大规模MIMO信道的近场效应和非平稳特性,该文提出适用大规模MIMO信道的一种基于随机散射簇的非平稳3D空间信道模型。采用抛物波前代替球面波前建模近场效应,并分析抛物波前条件下该模型的信道容量。对于大规模MIMO信道的非平稳特性,提出基于散射簇的有效概率确定收发天线阵元的有效散射簇集合,从而建模散射簇沿天线阵列轴的随机演变来合理描述散射簇的出现和消失。仿真结果表明,用抛物波前和有效散射簇的随机演变来建模大规模MIMO信道特征是很好的候选方法。     

一种新的MIMO无线信道建模方法

文中提出了一种时变宽带MIMO信道的建模方法。该方法利用修正的Jakes衰落模型，用正弦波形叠加的方法，建立了一个频率选择性瑞利衰落多普勒MIMO信道模型。MATLAB仿真证实了该方法的可行性。     

A physical scattering model for MIMO macrocellular broadband wireless channels

This paper presents a physical scattering model that predicts multiple-input multiple-output (MIMO) channel characteristics conforming well to experimental observations in macrocells. Our approach is to start with a given single-input single-output power-delay profile (defined for specific range, bandwidth and antenna parameters) and fit a scattering model that characterizes the MIMO channel. From the derived scattering model and antenna array configurations, the MIMO channel is computed using a ray-based method. Simulations of several MIMO channels are shown to exhibit experimentally observed channel correlations, antenna beamwidth effect, range dependency, and frequency selectivity.     

Modeling and Realization of Mobile-to-mobile Wideband MIMO Channels Based on the Geometrical Multi-Rings and Multi-Ellipses Stochastic Scattering Model

A geometry-based stochastic scattering model (GBSSM) based on geometrical multiple rings and ellipses is proposed for wideband multiple-input multiple-output (MIMO) mobile-to-mobile (M2M) fading channels. The proposed GBSSM is deployed with cross-polarized antennas and can be applied for the line-of-sight (LOS) and non-LOS (NLOS) scenarios by considering the single-bounced (SB) and double-bounced (DB) components. The channel realization is much more straightforward and concise to study the channel characteristics compared with the too complicated analytical solutions available so far. Based on the proposed GBSSM and realized channel, the channel characteristics and parameters at 2 GHz and 5 GHz with 100 MHz bandwidth are further investigated. The results can be used in the link and system level simulations in mobile-to-mobile radio systems.     

Deep learning-based channel estimation for wireless ultraviolet MIMO communication systems

To solve the problems of pulse broadening and channel fading caused by atmospheric scattering and turbulence, multiple-input multiple-output(MIMO) technology is a valid way. A wireless ultraviolet(UV) MIMO channel estimation approach based on deep learning is provided in this paper. The deep learning is used to convert the channel estimation into the image processing. By combining convolutional neural network(CNN) and attention mechanism(AM), the learning model is designed to extract the depth f...