共查询到18条相似文献,搜索用时 593 毫秒
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本文分析了小尺度无线衰落信道的理论参考模型—Clark模型,比较了两种较为重要的确定性仿真模型的参数计算方法—精确多普勒扩展法(MEDS)和随机精确多普勒扩展法(R_MEDS),提出了一种新的用于仿真平坦衰落信道Jakes模型的参数计算方法,即在MEDS的基础上对离散多普勒频率引入随机抖动。仿真数据和图形表明,在模型复杂度较低的情况下,新的信道模型的自相关和互相关特性较R_MEDS有很大改善,而且与原始MEDS相比,新模型多普勒频率为随机变量,可以有效仿真瑞利衰落、多个不相关的瑞利衰落和频率选择性衰落信道等,并且可以结合工程需要设定随机抖动幅度,保证了衰落信道的不相关性和遍历性的有机统一。 相似文献
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以经典Jakes模型的发展为线索,分析比较了具有代表性的改进Jakes类和非Jakes类模型,通过以瑞利衰落波形的二阶统计特性为判别信道效能的依据,得出高效信道模型所具有的参数特征以及仿真多个独立瑞利衰落波形的方法等.仿真数据表明,模型的精确度是以计算量和复杂度为代价. 相似文献
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在无线通信系统的仿真中,相关瑞利衰落信道扮演着重要的作用。一种基于对一系列统计独立的标准高斯随机过程进行线性变换,得到具有一定相关特性的瑞利衰落信道的仿真模型被提出。仿真结果及复杂度分析表明,由于本文提出的仿真模型采用了迭代算法,因此相对于传统的相关瑞利信道仿真模型,该模型具有准确,复杂度低,易实现等优点。 相似文献
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针对多输入多输出(Multiple-Input Multiple-Output,MIMO)无线传播环境,综合考虑路径损耗、阴影衰落和多径衰落影响,提出一种基于Nakagami-Lognormal分布的相关复合衰落MIMO信道模型,推导并获得各信道自相关和互相关系数的理论表达式;提出一种基于谐波叠加思想的复合衰落MIMO信道仿真方法,并分析了该方法输出信道衰落的空时相关特性.数值仿真结果表明:仿真模型输出统计特性均与理论模型吻合;各子信道之间存在互相关性且随阴影衰落方差减小而下降,而自相关性则呈现快速起伏并缓慢下降的特性. 相似文献
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信道模拟器是进行无线信道理论研究、通信新技术开发、新设备和系统性能测试不可或缺的仪器之一,针对SR-5500信道模拟器的不足,设计了一种基于FPGA的能够在中频频段上模拟典型无线信道特性的信道模拟器,对其设计中的有效字长效应进行了详细分析和理论推导,分析和仿真了恒参信道、瑞利衰落信道和多重分集瑞利衰落信道下"截断效应"对信道模拟器性能的影响,仿真结果表明当分别采用16 bit和32 bit精度产生高斯白噪声与衰落信道时,信道模拟器的测试误差在0.1 dB以内,满足测试要求,可为今后的工程应用和实现提供参考。 相似文献
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移动通信过程中由于移动设备所处的环境不同,存在不同的信道衰落,从各种衰落模型的相互关系出发,提出了一种移动无线衰落信道混合应用模型。通过实现瑞利衰落分布和对数正态分布,经线性和非线性变换可以得到Nakagami和Suzuki等分布。对提出的复合衰落模型进行仿真,仿真结果符合理论值。该混合衰落模型设计和仿真方法可以用于指导信道模拟器设计和通信系统仿真。 相似文献
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瑞利衰落信道Jakes模型的研究与性能分析 总被引:1,自引:0,他引:1
无线衰落信道是无线通信系统的重要组成部分,因此信道建模和仿真对于无线通信系统的开发具有极其重要的作用。文章通过对平坦瑞利(Rayleigh)衰落信道进行仿真建模研究,给出了瑞利衰落信道可以采用Jakes模型进行建模的分析结果。 相似文献
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The simulation of independent Rayleigh faders 总被引:2,自引:0,他引:2
Yunxin Li Xiaojing Huang 《Communications, IEEE Transactions on》2002,50(9):1503-1514
Multiple independent Rayleigh fading waveforms are often required for the simulation of wireless communications channels. Jakes (1974) Rayleigh fading model and its derivatives based on the sum-of-sinusoids provide simple simulators, but they have major shortcomings in their simulated correlation functions. A novel sum-of-sinusoids fading model is proposed and verified, which generates Rayleigh fading processes satisfying the theoretical independence requirements and providing desired power spectral densities with ideal second-order moment. The effects of replacing sinusoids in the proposed model by their approximate waveforms are also analyzed and tested. Performance evaluation and comparison are provided, using the quality measures of the mean-square-error of autocorrelation function and the second-order moment of the power spectral density. 相似文献
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Matthias Pätzold Bjørn Olav Hogstad Dongwoo Kim 《Wireless Personal Communications》2007,40(3):267-279
In this paper, we introduce a new technique for the design of high-performance Rayleigh fading channel simulators. The proposed
design method uses set partitioning – a technique, which plays a key role in the design of trellis-coded modulation schemes.
We show how set partitioning can be used to design multiple uncorrelated fading waveforms enabling the simulation of Rayleigh
fading channels. For the important case of isotropic scattering, we show that the sample average of the generated waveforms
results in a deterministic process, the autocorrelation function (ACF) of which tends to the zeroth-order Bessel function
of the first kind as the number of sample functions increases. The proposed procedure is completely deterministic. The comparison
with a stochastic procedure using Monte Carlo techniques will be made. A study of the performance shows clearly that the new
technique using set partitioning outperforms by far existing Monte Carlo methods. 相似文献
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Jakes fading model revisited 总被引:27,自引:0,他引:27
The Jakes fading model is a deterministic method for simulating time-correlated Rayleigh fading waveforms and is still widely used today. However, since it is difficult to create multiple uncorrelated fading waveforms with this model, the authors propose modifications to the model which solve this problem.<> 相似文献
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The computer generation of multiple cross-correlated Rician fading channels is investigated. We prove that the output sequences of existing multichannel fading simulators are restricted to have cross-correlation statistics that have the same functional form as the component autocorrelation functions. To overcome this limitation, vector autoregressive stochastic models are proposed for the generation of multiple Rician fading processes with specified realizable autocorrelation and cross-correlation statistics. This capability is desirable, for example, to permit realistic performance assessments of space-time modem designs by enabling the simulation of space-time-selective wireless channel models. The utility of the simulation approach is demonstrated by the accurate synthesis of some bandlimited multichannel Rayleigh and Rician processes. 相似文献
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Yahong Rosa Zheng Chengshan Xiao 《Communications, IEEE Transactions on》2003,51(6):920-928
In this paper, new sum-of-sinusoids statistical simulation models are proposed for Rayleigh fading channels. These new models employ random path gain, random initial phase, and conditional random Doppler frequency for all individual sinusoids. It is shown that the autocorrelations and cross correlations of the quadrature components, and the autocorrelation of the complex envelope of the new simulators match the desired ones exactly, even if the number of sinusoids is as small as a single-digit integer. Moreover, the probability density functions of the envelope and phase, the level crossing rate, the average fade duration, and the autocorrelation of the squared fading envelope which contains fourth-order statistics of the new simulators, asymptotically approach the correct ones as the number of sinusoids approaches infinity, while good convergence is achieved even when the number of sinusoids is as small as eight. The new simulators can be directly used to generate multiple uncorrelated fading waveforms for frequency selective fading channels, multiple-input multiple-output channels, and diversity combining scenarios. Statistical properties of one of the new simulators are evaluated by numerical results, finding good agreements. 相似文献
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Cheng-Xiang Wang Dongfeng Yuan Hsiao-Hwa Chen Wen Xu 《Wireless Communications, IEEE Transactions on》2008,7(9):3307-3311
The generation of multiple uncorrelated Rayleigh fading waveforms is often demanded for simulating wideband fading channels, multiple-input multiple-output (MIMO) channels, and diversity-combined fading channels. In this letter, an improved deterministic sum-of-sinusoids (SoS) channel simulator with a new parameter computation method is proposed to simulate a large number of uncorrelated Rayleigh fading processes. Compared with the existing SoS channel simulators, the proposed deterministic SoS model yields a much better simulation efficiency while still preserving satisfactory approximations to the desired statistical properties of the reference model. 相似文献
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针对多输入多输出(Multiple-Input Multiple-Output,MIMO)无线通信系统,在基于Kronecker 的MIMO信道模型中综合考虑了路径损耗、阴影衰落和多径衰落等因素,实现了基于现场可编程门阵列(Field Programmable Gate Array,FPGA)的MIMO信道模拟器,并分析了硬件设计方案以及MIMO信道模拟的实现方法。实测结果表明,设计的MIMO信道模拟器可以模拟瑞利衰落、莱斯衰落以及阴影衰落等常见的信道衰落类型,能够应用于3GPP、COST-207等标准信道模型的复现。该模拟器可作为无线通信系统研究的测试设备,辅助通信系统研究的算法验证、方案优化以及性能分析。 相似文献