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频率选择性衰落MIMO信道容量分析 总被引:1,自引:0,他引:1
随着传输速率越来越高,信号所占用的带宽越来越宽,实际信道呈现出频率选择性衰落特性.根据频率选择性衰落信道特性,建立了频率选择性衰落MIMO信道模型,采用频域和时域的方法研究了在频率选择性衰落下,发射端已知和未知信道状态信息的MIMO信道容量,并给出了相关的仿真结果.研究结果表明:在相同发射功率和传输带宽下,MIMO系统可以不牺牲信号带宽而显著提高信道的容量,并且天线数量和输入信噪比的大小对信道容量具有不同的影响.研究结果为如何提高频率选择性衰落环境下MIMO信道容量提供了依据. 相似文献
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多输入多输出(MIMO)通信系统相比其他的通信系统具有更高的频谱效率,在不增加发射功率以及信号带宽的情况下,MIMO技术可以有效地提高系统信道容量及其性能。利用均匀角能量分布以及相关矩阵,分析了相关信道下的MIMO系统信道容量,得出了系统信道容量的通用公式,并利用MATLAB进行仿真。仿真结果表明,相关性的增加意味着信噪比的减小,圆形接收天线阵列半径与角度扩展是决定MIMO系统信道容量的主要因素。 相似文献
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MIMO-OFDM系统的信道容量分析 总被引:1,自引:0,他引:1
研究TMIMO-OFDM系统在频率选择性衰落信道下的系统模型,推导了使用等功率分配时的信道容量,得出了各态历经容量的一个紧密下界.分析了天线数目、接收信噪比及选择性衰落分集对信道容量的影响.通过仿真表明,MIMO-OFDM系统信道容量主要由天线数目和平均接收信噪比决定,随着天线数目或信噪比的增加而增大. 相似文献
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OFDM技术能将频率选择性信道转变为平坦衰落信道,而MIMO技术在平坦衰落信道上可显著提高信道容量,从而大幅度提高频谱效率。本文分析了MIMO—OFDM系统中加性高斯自噪声(AWGN)信道的信道容量。 相似文献
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《现代电子技术》2018,(1):17-22
电力通信网络的架构及无线信道特性是决定网络性能的关键因素。首先,研究基于南方电网电力无线宽带专网的双层无线接入架构,该架构中宏蜂窝与汇聚网关之间的MIMO信道的性能将直接影响到电网的稳定和运营水平。因此,对MIMO信道性能的研究就尤为重要。主要对MIMO信道的两个典型模型WINNERⅡ模型和Kronecker模型分别从信道空间相关性、信道容量、时域衰落三方面进行理论分析与对比仿真。由仿真结果得到天线数量、信噪比、天线阵列等因素对信道容量和天线相关性的影响。仿真结果说明MIMO技术能够在电网多业务承载环境下,满足系统高速率、大容量的要求。通过比较,WINNERⅡ模型与真实传播环境匹配度高,可在双层无线接入架构中得到进一步的应用。 相似文献
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室内可见光MIMO信道的空间相关性分析 总被引:4,自引:0,他引:4
该文针对室内可见光多输入多输出(MIMO)信道的空间相关性展开研究,基于朗伯辐射模型,建立了室内可见光MIMO信道模型;并基于该模型,分析了发送与接收空间相关性与空间距离参数的关系,给出了发送与接收相关系数的表达式,为室内可见光MIMO通信系统的布设提供了理论指导;信道矩阵条件数仿真验证了信道空间相关性随发光二极管(LED)间距的减小而增大、随光电检测器(PD)间距的减小而增大、随LED到PD垂直距离的增大而增大;信道容量仿真得出,随着LED与PD数量的增加,信道容量逐步提高,但随着信道空间相关性的增强,信道容量的提高逐步减小。 相似文献
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基于实际场景测量,对地铁隧道有限空间Massive MIMO性能进行了研究。采用复用天线阵列法实现收发同步切换分时虚拟MIMO测量。基于测量数据,主要分析了3.5 GHz和5.6 GHz频段Massive MIMO信道在隧道场景的性能,研究了信道矩阵的特征值分布和条件数,着重分析了不同收发天线距离对Massive MIMO信道容量的影响,考虑了基于信噪比的有效秩选择方法。研究结果表明,在3.5 GHz及5.6 GHz频段上,Massive MIMO信道矩阵条件数的范围处在30 dB至55 dB之间,信道容量有较大的提升,且信道矩阵的有效秩随收发机距离增大的衰减趋势明显。以上结果对隧道场景下一代无线通信系统的设计与部署提供了依据。 相似文献
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We investigate the sum capacity of Block Diagonalization precoding Multiple Input Multiple Output Broadcast Channels (BD MIMO BC) with imperfect Channel State Information (CSI) at the base station. Since it is difficult to obtain the exact expression, a lower and an upper bounds of the sum capacity under Gaussian channel estimation errors are drived instead. Analyses show that the gap between two bounds is considerably tight at all Signal to Noise Ratio (SNR) region. From the lower bound of the sum capacity, we can see that the multiplexing gain tends to be zero at high SNR region, which indicates that the BD MIMO BC system with channel estimation errors is interference-limited at high SNR. 相似文献
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LI Yong-hua Lü Tie-jun WU Xiao-fei ZHANG Lin Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts Telecommunications Beijing China 《中国邮电高校学报(英文版)》2010,17(2):8-13
The multi-input multi-output (MIMO) technology plays an important role in link transmissions. This article considers the general case for the ergodic capacity in doubly correlated frequency-selective MIMO channel. In the study, the geometrical MIMO channel model is presented. Based on the formula of MIMO ergodic capacity, the capacity limits are studied with arbitrary finite number of antennas in the frequency-selective MIMO channel. It first derives the exact expressions for the upper bound and lower bound in doubly correlated MIMO channel. The results for the single-ended correlation and independent identically distributed (i.i.d.) MIMO channel are also obtained as special cases. Then the simple expressions of the capacity bounds are attained at high SNR. Finally, results are provided by Monte Carlo simulations to verify the tightness of the derived bounds. 相似文献
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This paper considers the ergodic capacity of spatially-correlated Rician MIMO channels. We address the case where the Rician component has a single dominant path and where the correlation occurs at one end of the MIMO link. We derive upper bounds which are tight for all signal to noise ratios (SNR), and lower bounds which converge to the exact capacity at high SNR. For frequency-flat channels we investigate the capacity variation with Rician K-factor and correlation. For frequency-selective channels we also examine the effect of the total angle spread. 相似文献
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Oyman O. Nabar R.U. Bolcskei H. Paulraj A.J. 《Signal Processing, IEEE Transactions on》2003,51(11):2784-2795
We consider Gaussian multiple-input multiple-output (MIMO) frequency-selective spatially correlated fading channels, assuming that the channel is unknown at the transmitter and perfectly known at the receiver. For Gaussian codebooks, using results from multivariate statistics, we derive an analytical expression for a tight lower bound on the ergodic capacity of such channels at any signal-to-noise ratio (SNR). We show that our bound is tighter than previously reported analytical lower bounds, and we proceed to analytically quantify the impact of spatial fading correlation on ergodic capacity. Based on a closed-form approximation of the variance of mutual information in correlated flat-fading MIMO channels, we provide insights into the multiplexing-diversity tradeoff for Gaussian code books. Furthermore, for a given total number of antennas, we consider the problem of finding the optimal (ergodic capacity maximizing) number of transmit and receive antennas, and we reveal the SNR-dependent nature of the maximization strategy. Finally, we present numerical results and comparisons between our capacity bounds and previously reported bounds. 相似文献
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MIMO system can provide higher capacity in independent conditions. When the spatial-temporal fading correlation exists, the capacity may decrease. In this paper, the geometrical MIMO channel model is presented with Rician factor. Based on the MIMO ergodic capacity, the capacity bounds are derived with arbitrary finite number of antennas.The bounds are derived in the exact expressions in doubly correlated MIMO Rician channel. Then a simple expression for the capacity bounds is attained for the high SNR. Finally, the tightness of derived bounds is verified by Monte Carlo simulation. 相似文献
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On the capacity of MIMO relay channels 总被引:10,自引:0,他引:10
Wang B. Zhang J. Host-Madsen A. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2005,51(1):29-43
We study the capacity of multiple-input multiple- output (MIMO) relay channels. We first consider the Gaussian MIMO relay channel with fixed channel conditions, and derive upper bounds and lower bounds that can be obtained numerically by convex programming. We present algorithms to compute the bounds. Next, we generalize the study to the Rayleigh fading case. We find an upper bound and a lower bound on the ergodic capacity. It is somewhat surprising that the upper bound can meet the lower bound under certain regularity conditions (not necessarily degradedness), and therefore the capacity can be characterized exactly; previously this has been proven only for the degraded Gaussian relay channel. We investigate sufficient conditions for achieving the ergodic capacity; and in particular, for the case where all nodes have the same number of antennas, the capacity can be achieved under certain signal-to-noise ratio (SNR) conditions. Numerical results are also provided to illustrate the bounds on the ergodic capacity of the MIMO relay channel over Rayleigh fading. Finally, we present a potential application of the MIMO relay channel for cooperative communications in ad hoc networks. 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》2005,51(9):3121-3145
This paper considers the capacity of spatially correlated Rician multiple-input multiple-output (MIMO) channels. We consider the general case with double-sided correlation and arbitrary rank channel means. We derive tight upper and lower bounds on the ergodic capacity. In the particular cases when the numbers of transmit and receive antennas are equal, or when the correlation is single sided, we derive more specific bounds which are computationally efficient. The bounds are shown to reduce to known results in cases of independent and identically distributed (i.i.d.) and correlated Rayleigh MIMO channels. We also analyze the outage characteristics of the correlated Rician MIMO channels at high signal-to-noise ratio (SNR). We derive the mean and variance of the mutual information and show that it is well approximated by a Gaussian distribution. Finally, we present numerical results which show the effect of the antenna configuration, correlation level (angle spreads), Rician$K$ -factor, and the geometry of the dominant Rician paths. 相似文献
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Multiple-input multiple-output (MIMO) wireless systems can achieve significant diversity and array gain by using single-stream transmit beamforming and receive combining. A MIMO beamforming system with feedback using a codebook based quantization of the beamforming vector allows practical implementation of such a strategy in a single-user scenario. The performance of this system in uncorrelated Rayleigh flat fading channels is studied from the point-of-view of signal-to-noise ratio (SNR) and outage probability. In this paper, lower bounds are derived on the expected SNR loss and the outage probability of systems that have a single receive antenna or two transmit antennas. For arbitrary transmit and receive antennas, approximations for the SNR loss and outage are derived. In particular, the SNR loss in a quantized MIMO beamforming system is characterized as a function of the number of quantization bits and the number of transmit and receive antennas. The analytical expressions are proved to be tight with asymptotically large feedback rate. Simulations show that the bounds and approximations are tight even at low feedback rates, thereby providing a benchmark for feedback system design 相似文献
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Zouheir Rezki David Haccoun Franois Gagnon Wessam Ajib 《Wireless Communications and Mobile Computing》2010,10(2):188-199
In this paper, we present a finite‐signal‐to‐noise ratio (finite‐SNR) framework to establish tight bounds on the diversity‐multiplexing tradeoff of a multiple input multiple output (MIMO) system. We focus on a more realistic propagation environment where MIMO channel fading coefficients are correlated and where SNR values are finite. The impact of spatial correlation on the fundamental diversity‐multiplexing tradeoff is investigated. We present tight lower bounds on the outage probability of both spatially uncorrelated and correlated MIMO channels. Using these lower bounds, accurate finite‐SNR estimates of the diversity‐multiplexing tradeoff are derived. These estimates allow to gain insight on the impact of spatial correlation on the diversity‐multiplexing tradeoff at finite‐SNR. As expected, the diversity‐multiplexing tradeoff is severely degraded as the spatial correlation increases. For example, a MIMO system operating at a spectral efficiency of R bps/Hz and at an SNR of 5 dB in a moderately correlated channel, achieves a better diversity gain than a system operating at the same spectral efficiency and at an SNR of 10 dB in a highly correlated channel, when the multiplexing gain r is greater than 0.8. Another interesting point is that provided that the spatial correlation channel matrix is of full rank, the maximum diversity gain is not affected by the spatial correlation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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We develop a semi-deterministic semi-stochastic channel model for the multiple-input multiple-output (MIMO) system under the macrocell environment with local-to-mobile and local-to-base scatterers. We show that employing closely-spaced antennas (e.g., phased array) at the base station is capable of achieving diversity via the local-to-base scatterers, which avoids impractical large aperture requirement for the spatial diversity at the base station. We evaluate the system performance in terms of ergodic capacity, average pairwise error probability (PEP), and signal-to-noise ratio (SNR); derive closed-form expressions for lower and upper bounds on the capacity and PEP; and show that the capacity, multiplexing and diversity gains are limited by the number of multipaths around the base station. The base-station array affects the lower bound on the capacity and the upper bound on the error probability through the same metric; thus, optimal design of the base station array based on this metric will optimize the two different information theoretic measures simultaneously. The fading correlation matrix also appears in the two bounds in the same form. To improve the performance of the macrocell MIMO system, we propose using artificial scatterers and discuss optimal design issues. Numerical examples demonstrate the accuracy of our analytical results and tightness of performance bounds. 相似文献