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协作多点(CoMP)传输技术是LTE—A系统的关键技术,能够有效抑制多小区同道干扰,从而提高整个系统和边缘用户吞吐量。但CoMP传输中系统性能极大地依赖于发端信道信息的精确程度。现有的研究基本是基于发端拥有完美信道信息的假设,但这在实际中是无法实现的。针对实际的有限反馈系统,提出了基于分层有限反馈的协作调度/协作波束成形算法。仿真结果表明:所提出的算法能够在保持CoMP传输高频谱效率优势的同时可以极大地降低系统反馈量和执行复杂度。 相似文献
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当主用户和次用户在地理上存在一定距离时,由于次用户到达主用户系统的信号不同步,会产生异步干扰,此干扰不但影响主用户系统,使得其干扰增大,也会影响次用户系统,使得次用户系统传输速率损失,特别是误比特性能上升。为了消除异步干扰对主次用户系统的影响,提出了一种基于最小均方误差的预编码方法,此方法在预编码阶段就预先消除了异步干扰,并且是在保证主用户的服务质量基础上进行的。通过分析和仿真结果表明,所提方案在对主用户系统干扰受限的条件下,有效提升了次用户系统和次用户系统的容量,同时提高了次用户系统传输的可靠性。 相似文献
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基于多用户多输入多输出(MIMO)有限反馈系统提出了一种收发联合波束成形方法。该方法在发送端采用每个用户酉速率控制(PU2RC)波束成形技术,在接收端采用基于信干噪比(SINR)最大化的天线合并算法。天线合并算法利用用户SINR的广义Rayleigh熵特性寻找最佳的天线合并矢量。仿真结果表明,该方法能充分利用信道信息,不仅改善了传统PU2RC系统的和速率性能,相对于已有的迫零(ZF)联合波束成形方法,对信道状态信息的量化误差的敏感性更低,用户选择算法的复杂度更低,且低速率反馈条件下和速率性能更优。 相似文献
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一种多区协同的区间干扰抑制方法 总被引:1,自引:1,他引:0
在LTE-Advanced系统中,小区频率复用因子为1,从而区间干扰会严重影响小区边缘用户接收性能。为减少数据交换量,提出一种基于用户划分的干扰抑制方法。首先根据用户接收功率估计,判断相邻小区内是否存在边缘用户,存在时,通过多区协同实现对该边缘用户的干扰抑制,而不存在时,则采取单小区多用户干扰抑制方法,与传统方法相比,该方法无需所有相邻小区用户的信道状态信息,从而大大减少了在基站间的数据交换量。文章介绍了该方法实现步骤,分析了实现复杂度,并通过对用户误码率仿真证明了算法性能。 相似文献
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在次用户配置的多天线的认知多天线协作反馈系统中,信道方向信息存在量化误差,现有的用户选择方法不能使次用户系统容量最大化,而且增大了对主用户系统的干扰。为了消除量化误差对主次用户系统的影响,提出了一种基于BD预编码的统计独立系数的用户选择方案。分析和仿真结果表明,所提方案在主用户系统干扰受限的条件下有效提升了次用户系统的容量。 相似文献
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针对蜂窝小区的干扰,给出了基于信干噪比(SINR)反馈的基站协作策略,采用SINR门限锁定系统边缘用户,避免了传统穷搜索算法的复杂性,在多小区规模上索引协作基站。基于SWF功率分配,采用SVD预编码设计。仿真表明,该方案既弱化了小区边缘用户受到的干扰,提高了系统信息吞吐量,又减少了高反馈量带来的复杂度,是一个很好的折中方案。 相似文献
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一种改进的PU2RC多模传输方法 总被引:1,自引:0,他引:1
在有限反馈的下行多用户多入多出(Multiuser multiple-input multiple-output,MU-MIMO)系统中,系统的和容量随着信噪比的升高而干扰受限。本文针对这个问题提出了一种改进的每用户归一化波束成形与速率控制(Per-user unitary beamforming and rate control,PU2RC)多模传输方案,通过增加信道量化质量指示的反馈,为基站进行用户选择提供了更有效的信息以实现多模传输。仿真结果表明,在实际系统中激活用户数比较少时,该方案能够通过动态改变同时服务的用户数,从而最大化系统的和容量。在同等反馈量的情况下,与传统的PU2RC相比,提高了系统的和容量,为下行MU-MIMO系统的应用提供了更好的参考。 相似文献
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S. Shaw 《Journal of Computer Assisted Learning》1993,9(2):93-99
Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained. 相似文献
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European Community policy and the market 总被引:1,自引:0,他引:1
C. Lloyd 《Journal of Computer Assisted Learning》1993,9(2):86-91
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven. 相似文献
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融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。 相似文献
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Wayne O’Brien Author Vitae 《Journal of Systems and Software》2008,81(11):1997-2013
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them. 相似文献
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This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives. 相似文献
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Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what
is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic
sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and
its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of
an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify
robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can
or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
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David Poole 《Computational Intelligence》1989,5(2):97-110
Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given. 相似文献
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Watts S. Humphrey 《Annals of Software Engineering》2002,14(1-4):39-72
This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)SM and Team Software Process (TSP){SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical. 相似文献
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基于复小波噪声方差显著修正的SAR图像去噪 总被引:4,自引:1,他引:3
提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。 相似文献