多业务交织多址接入(IDMA)通信系统的连接接纳控制方法

作为第四代移动通信关键技术之一的交织多址接入(IDMA)技术受到了很大关注。连接接纳控制(CAC)技术是其无线资源管理中必不可少的组成部分,针对现有的CAC方法均是建立在TDMA和CDMA系统上,并且不适用于IDMA系统的研究现状,提出了一种基于SINR改进技术的接纳控制方法(SE-CAC),该方法的关键就是将基于IDMA系统的逐码片(CBC)迭代多用户检测技术(MUD)的系统性能分析方法 SINR Evolution技术应用到接纳判决的过程中,在精确预测MUD对系统性能影响的同时,简化了算法的复杂度。IDMA的研究动机正是其对抗小区内部多址干扰的高效率,因此,SE-CAC方法非常适合应用于IDMA系统。仿真结果表明,和传统的近似MUD效率为固定常数的CAC方法相比较,本文的SE-CAC方法保证了IDMA系统具有更高的吞吐量和功率利用率,并且在重负载情况下,IDMA性能优势更为明显,充分显示了IDMA-CBC MUD的高效率。     

基于LDPC编码的交织多址接入（IDMA）系统

交织多址接入（IDMA）技术是第四代移动通信的关键技术之一，为了使该系统更加接近多址接入的信道容量限，设计了一种基于LDPC码编码的交织多址接入（IDMA）系统，并将它与传统的基于卷积码编码的IDMA系统在高斯白噪声（AWGN）信道下进行了性能比较。仿真结果发现，随着信噪比的增加，该系统的多用户性能曲线会逐渐向单用户性能曲线靠近；16个用户时该系统在误比特率为10^-6情况下离多址接入的信道容量限大约是2．6dB，而相同条件下，基于卷积码编码的系统大约是6．0dB。清楚地表明：设计的系统更加接近多址接入的信道容量限，可以获得更多的编码增益。在实际应用中，非常适合于高速的数据传榆业务。     

基于LDPC编码的交织多址接入(IDMA)系统

交织多址接入（IDMA）技术是第四代移动通信的关键技术之一,为了使该系统更加接近多址接入的信道容量限,设计了一种基于LDPC码编码的交织多址接入（IDMA）系统,并将它与传统的基于卷积码编码的IDMA系统在高斯白噪声(AWGN)信道下进行了性能比较。仿真结果发现,随着信噪比的增加,该系统的多用户性能曲线会逐渐向单用户性能曲线靠近;16个用户时该系统在误比特率为10-6情况下离多址接入的信道容量限大约是2.6 dB,而相同条件下,基于卷积码编码的系统大约是6.0 dB。清楚地表明：设计的系统更加接近多址接入的信道容量限,可以获得更多的编码增益。在实际应用中,非常适合于高速的数据传输业务。     

基于EXIT图的LDPIDMA系统性能分析

交织多址接入(interleavedivision multipleaceess system,IDMA)技术是第四代移动通信的关键技术之一,为了使该系统更加接近多址接入的信道容量限,设计了一种基于LDPC码编码的交织多址接入(IDMA)系统。利用基于互信息的EXIT图工具,从信息论的角度对LDPC码应用于交织分多址系统的性能进行预测和分析。分析结果表明, LDPC码非常适合于IDMA系统,相比无编码系统而言,在AWGN信道下多用户的系统性能得到了明显的改善,同时也验证了EXIT图分析迭代系统性能的有效性。     

基于EXIT图的IDMA系统性能分析

交织分多址接入（IDMA）技术是第四代移动通信的关键技术之一 。IDMA系统采用一个简单的逐码片的迭代多用户检测接收结构,利用交织器来区分用户。用外信息传输（EXIT）图分析IDMA系统在不同的系统参数下的性能,如用户数、扩频长度、信道的信噪比。仿真结果证明,EXIT图技术能准确地分析IDMA系统的性能。     

基于EXIT图的LDPC—IDMA系统性能分析

交织多址接入(interleave-division multiple-aceess system,IDMA)技术是第四代移动通信的关键技术之一.为了使该系统更加接近多址接入的信道容量限,设计了一种基于LDPC码编码的交织多址接入(IDMA)系统.利用基于互信息的EXIT图工具,从信息论的角度对LDPC码应用于交织分多址系统的性能进行预测和分析.分析结果表明,LDPC码非常适合于IDMA系统,相比无编码系统而言,在AWGN信道下多用户的系统性能得到了明显的改善,同时也验证了EXIT图分析迭代系统性能的有效性.     

关于交织多址时空码的设计

交织多址时空码(IDM-ST)系统是交织多址(IDMA)系统的延伸和演化,它将基于发射分集技术的空时码思想应用于IDMA系统中,使得IDM-ST系统接近于所谓的规范化性能,具有接收简单,复杂度低等优点.介绍了IDM-ST系统的基本原理及其算法流程并对其发展前景进行了预测.     

一种基于IDMA的非正交多用户检测方法

为了提高系统容量、频谱效率和传输速率,针对第五代通信网络业界提出了功率域非正交多址接入PDNOMA方式,通过功率域叠加复用增加用户接入数量,并且通过串行干扰消除SIC来检测用户信号。SIC算法简单,但性能一般,随着叠加的用户个数的增加,系统的性能会大大下降。交织多址接入IDMA可以采用特定的交织器来分离各用户,并允许使用低复杂度迭代多用户检测技术。为了提高性能,结合基于IDMA的非正交多用户系统和PDNOMA在接收端提出一种迭代检测方法 ISICPIC。仿真表明ISICPIC适用于多用户同时传输的情况,系统性能较好且不会随着用户数的增加而下降。     

基于Verilog的IDMA系统发射端和接收端设计

交织多址IDMA作为一种无线接入多址技术,不仅具有码分多址CDMA技术优势,而且采用交织图机制分离用户,避免了CDMA中受限于扩频码长度分离用户机制的瓶颈。IDMA接收端运用迭代多用户检测技术,在计算复杂度增加较少的情况下,有效提高了频谱利用率。基于IDMA的技术原理,运用Verilog针对IDMA的发射端和接收端进行了仿真设计。实验仿真表明:基于Verilog的IDMA系统的发射端和接收端的设计与理论分析一致,达到了设计要求。     

干扰抵消多用户检测

在CDMA（码分多址）系统中由于多址干扰（MAI）的存在,使得CDMA系统成为一个干扰受限系统,而多用户检测（MUD）已经成为解决这一问题的一种有效途径。本文从多址干扰（MAI）入手重点阐述了DS-CDMA的多用户检测的基本原理,通过分析多址干扰的产生的原因,本文绍了两种基于干扰抵消的多用户检测。最后仿真了这两种多用户检测对于消除多址干扰的效果。     

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.     

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.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.