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给出了一种频率选择性信道下空间相关MIMO的系统模型,其发送端采用准循环系统RA码,接收端采用一种对空间相关和非相关信道均适用的软干扰消除迭代检测算法.该算法首先采用基于最小均方误差检测(MMSE)的滑动窗口模型进行干扰消除,然后采用多天线联合最大似然检测(ML)以得到软信息,再将得到的软信息传递到译码器译码并输出发送比特的软信息作为下一次迭代的先验信息,即完成一次迭代.此模型能够取得比较好的误码率性能(BER),其改进方案既增加了发送端的调制域分集,性能又有提升.作为比较,基于软干扰消除的逐天线MMSE迭代检测的方案(ABA SC/MMSE)性能很差.仿真结果也证明了以上观点. 相似文献
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基于导频序列推导了频率平坦多输入多输出(MIMO)信道下的最小二乘信道估计(LS)误差;将信道估计误差等效为高斯噪声,推导了信道估计条件下系统的等效信噪比,提出了用系统的等效信噪比来分析和评估在信道估计误差条件下系统的误码性能;最后用等效信噪比的方法评估了ZF-V-BLAST算法在信道估计下的性能,结果表明和计算机仿真结果基本相吻合。 相似文献
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根据加权粒度的差别,介绍了per-RB-MRT算法和full-BW-EBB算法的原理,并对这两种算法
的特点以及性能差异进行了理论
分析。构建了符合3GPP规范定义的TD-LTE系统上下
行仿真平台,对这两种算法在有信道估计误差(包括信道估计精准度和信道信息时延)的情
况下的其性能进行了理论分析和仿真研究。仿真结果表明,per-RB-MRT算法在上行信道
估计值和
下行信道实际值契合较好的情况下能够趋于最佳理论性能,而full-BW-EBB算法由于利用了
相对稳定的信道空间相关特性,因而能够在较差的信道环境中保持较高的性能鲁棒性。这
些仿真结果对于实际场景中的算法选择提供了重要的参考依据。 相似文献
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随着设备小型化的发展趋势,天线间距较小,信道具有相关性;且假设发射端处于高速移动状态,无法获得完全信道状态信息,只能根据部分信道状态信息设计发射端波束形成方案。针对发射端和接收端配置多天线的固定增益放大转发无线中继系统,以最大化接收端信噪比为准则,设计了基于部分信道状态信息的波束形成方案,推导了系统中断概率和平均误符号率的闭合表达式,通过仿真验证了性能分析的有效性和所设计方案的优越性。在平均误符号率为10-2、相关系数为0.8时,所提方案比反馈信道状态信息的方案节约1.6 dB的信噪比。 相似文献
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基于层次分析法的财务人员绩效评估指标权重分析 总被引:1,自引:0,他引:1
丁洁 《商业经济(哈尔滨)》2009,(4)
绩效评估的公平性一直是人力资源管理最为关注的问题之一,如何科学、客观、精确地分配缋效评估指标权重,对实现员工的公正评估尤为重要.财务人员的缋效评估有着自身的独特性,其绩效衡量指标多以定性指标为主,存在很大的随意性,而现有的绩效评估权重确定方法主观性强,精度不够,用于财务人员的绩效评估会大大降低其精准性.针对财务人员自身的特点,将层次分析法引入到财务人员绩效评定当中,将定量和定性相结合,解决了以往凭经验确定指标权重导致缋效评估失衡的问题. 相似文献
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创业在实践中的回归引起了学术界的极大关注,但是创业绩效的内涵却依旧模糊。本文紧紧围绕"创业绩效是什么"这一创业领域的核心问题,在修正了基于合约的创业绩效理论的基础上,构建了由生存、成长、声誉等三个维度组成的创业绩效结构模型,其有效性在实证研究中通过验证性因素分析得到了验证。 相似文献
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The objective of this paper is to provide empirical evidence on the influence of corporate governance characteristics and corporate ownership concentrations on the financial performance of Chinese companies. This is based on analysis of a panel data set covering the years 2001 to 2005. The characteristics considered are the ratios of independent directors and professional supervisors on the companies' two boards, and the level of concentration in and type of ownership of the companies. Our chosen performance metric is Tobin's Q. We find that ownership concentration in general is a significant factor in determining firm performance. The degree of board independence is significant, but it only appears to have a positive impact on performance in larger companies. The expertise of the supervisory board is not a significant determinant of corporate financial performance in China. Our findings support a continued focus on making improvements to the operation and effectiveness of China's institutions of corporate governance. 相似文献
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Effects of IT knowledge and media selection on operational performance of small firms 总被引:1,自引:0,他引:1
This study examines the effects of information technology (IT) knowledge and media selection on operational performance, measured
by balanced scorecard, in small firms. Small firms generally lag behind medium and large companies in adopting and implementing
computerization. This study is based on a survey of 698 small firms. The results show that: (1) individual IT knowledge and
both traditional and electronic communication methods significantly contribute to the internal process performance of small
firms; (2) internal process performance, organizational IT knowledge, and electronic communication methods affect customer
performance; and (3) financial performance is affected by process and customer performance. The findings imply that it is
imperative for small firms to adopt computerization to achieve improvements in business performance.
相似文献
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基于战略人力资源管理理论,在文献回顾的基础上,将人力资源柔性作为中介变量引入到高参与工作系统对工作绩效作用机制的研究中,同时运用多元线性回归和结构方程模型方法对假设理论模型进行实证分析。研究结果表明:高参与工作系统对人力资源柔性、工作绩效具有显著正向影响;高参与工作系统四个维度对人力资源柔性等有正向影响;人力资源柔性在高参与工作系统与工作绩效关系中起部分中介作用,增强人力资源柔性对提高工作绩效有重要作用。 相似文献
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Timing is everything: A meta-analysis of the relationships between organizational performance and innovation 总被引:1,自引:0,他引:1
The relationship between innovation and firm performance has been uncertain. In previous empirical tests of both causal directions of the organizational performance and innovation relationship, the temporal sequence of research designs has often been flawed. We meta-analytically test both temporal sequences of this relationship using 158 effect sizes from 55 empirical studies. We find that many empirical studies hypothesized one temporal sequence (e.g. innovation and future performance), but used data based on the opposite temporal sequence (e.g. past performance and innovation). Correcting the studies based on the actual temporal sequence used reveals that while the relationship between innovation and future performance is positive (based on economic rent-seeking), the relationship between past performance and innovation is less clear, especially when the study's framing is taken into account. Focusing on temporal sequencing suggests new research avenues on the organizational performance and innovation relationship. 相似文献
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Beatriz Minguela-Rata José Ignacio López-Sánchez M. Concepción Rodríguez-Benavides 《Service Business》2009,3(1):101-115
The literature of knowledge transfer studies complexity as a knowledge characteristic which influences organisations’ performance since it hinders this process. However, complex knowledge is richer and more complete and its influence on performance may be positive. So, the purpose of this study is to analyse the influence of knowledge complexity on the performance of franchise systems in the service industries. With this aim, a linear regression analysis is conducted on a sample of franchisee of different franchise chains of the several service industries operating in Spain. The findings seem to indicate that complexity has a positive impact on the performance of franchise systems. 相似文献