改进的VBLAST检测算法及其在多载波CDMA系统中的应用

将多输入多输出(MIMO)技术应用于传统的MC\DS CDMA方案,构成MIMO MC\DS CDMA系统,能在很大程度上提高MC\DS CDMA方案的性能。在深入研究低复杂度的QR分解相关算法的基础上,提出了一种MIMOMC\DS CDMA系统中改进的VBLAST检测算法——平行干扰消除QR分解检测算法,该算法进一步抑制了误码传播现象。仿真结果表明,所提出的算法无论是在单用户或者多用户条件下都能显著提高系统的误码率性能。     

基于优化混沌扩频序列的DS／CDMA系统

混沌序列以其相关性好、对初值敏感、保密性强等特性成为直序码分多（DS／CDMA）系统中性能较好的一种扩频码．为了提高DS／CDMA系统保密性,降低多址干扰,提出了一种优化作为扩频码的混沌序列性能的算法,并将该算法运用于常用的3种混沌序列,比较了优化后的混沌序列应用于DS／CDMA系统中的性能,结果表明,优化后的改进型Chebyshev序列能提供较大的系统容量,抗多址干扰能力强,且系统误码率较低．     

适用于CDMA系统的DOA算法

提出了一个直扩码分多址 (DS CDMA)通信系统的接收信号模型 ,并在此模型的基础上推导出一种适用于DS CDMA系统的DOA (DirectionsofArrival)算法 .算法利用期望用户的扩频序列与接收信号的信号子空间的关系 ,来估计信号的DOA .该算法突破了在传统的DOA算法中检测的DOA数要小于阵列的天线数的限制 ,其性能也远远好于一般的DOA算法     

基于瑞利信道的MC-DS-CDMA时频交织方案设计与分析

在分析介绍无线信道瑞利衰落特征和MC DS CDMA(多载波直扩码分多址)系统模型的基础上,设计并构建了MC DS CDMA系统的一种时频交织/解交织方案。通过对几种不同的交织方案的仿真分析,比较了不同的方案对MC DS CDMA系统性能的影响,使得该方案比同样深度的块交织可以获得至少1dB的增益。     

DS—CDMA中自适应多用户检测接收机的研究

直接序列扩频的CDMA系统是用扩频序列直接对待传信息信号作频谱扩展构成的CDMA通信系统,简称为直扩CDMA系统（DS—CDMA）,是最典型的CDMA系统。本论文介绍了直接序列扩频的CDMA通信系统的组成和特点,并以DS—CDMA系统的自适应多用户检测接收机为例进行分析并利用Simulink模块以及M文件的使用来进行仿真。     

CDMA中的多用户检测技术及研究动态

多用户检测是解决DS—CDMA系统中MAI的关键技术。在介绍MUD原理的基础上,对现有一些算法的性能、特点和不足进行了分析,并指出了多用户检测的发展方向。     

一种盲自适应判决反馈均衡器在DS/CDMA系统中的设计实现

在二进制DS/CDMA系统,考虑某一个目标用户,把其它用户看作干扰,设计了一种盲判决反馈自适应均衡器对色散信道进行均衡,使用自适应恒模(CMA)算法并对算法进行了仿真.其能够抑制多址干扰,消除码间串扰.     

两种恒模波束形成算法性能分析

论文介绍了最陡下降和最小二乘两种恒模波束形成算法，在DS—CDMA系统中，就两种算法的收敛性能和稳态性能．进行了MATLAB实验仿真，结果表明，两种算法在恒模波束形成中的性能差别明显。     

一种低复杂度的Turbo多用户检测技术

基于Turbo原理 ,提出了一种适合于同步DS CDMA系统的迭代多用户接收机结构 ,它通过在反复迭代的软输入软输出多用户检测器和一组信道译码之间获得连续的软判决 ,从而得到一种低复杂度的多用户检测算法———软MMSE干扰消除     

多径信道下基于最小平均峰度准则的盲多用户检测算法

基于最小平均峰度(LMK)准则,提出了一种适用于同步直扩码分多址(DS/CDMA)系统多径慢衰落信道中的盲自适应多用户检测算法.这种算法基于高阶统计量特性,算法复杂度相对较低.仿真结果表明,该算法的稳态性能与子空间自适应多用户检测算法相当,是一种较好的多用户检测算法,有一定的实际应用价值.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that