从2代过渡到3代——TSM移动通信系统

介绍一种运行于GSM核心网络而以TD-SCDMA物理层为基础的系统TSM系统.TSM 系统提 出的初衷一方面是为了解决以GSM 作为第二代移动通信主要技术的运营商向第三代移动通信平滑过渡 的问题;另一方面也是为TD-SCDMA统的现场试验提供一个规范.SM 系统提出在GSM 网络中,用 TD-SCDMA技术提供第三代移动通信业务的概念和实现方法,此技术在GSM 系统向第三代移动通信 过渡的时期将有重要的现实意义.     

面向LTE基站的SoC平台软件

从第一代模拟无线网络、第二代GSM通信网络、第三代3G通信网络到目前商用的4G LTE通信网络,直至正在研究的5G通信网络,移动通信技术的发展异常迅猛.从GSM 的TCH9.6Kbps、GPRS的171Kbps、WCDMA及TDSCDMA的384Kbps、HSDPA的14.4Mbps到目前LTE的下行100Mbps,数据的传输速率也越来越快.     

第三代移动通信系统

所谓第三代移动通信系统是指相对于第一代采取模拟技术的移动通信系统和采用数字技术的第二代移动通信系统而言的。第一代移动通信系统制式繁多,世界各国所采用的制式也不相同,北美和澳大利亚采用AMPS,英国采用TACS、瑞典等国采用NMT450、NMT900。意大利等采用RTMS,法国采用RC2000,而我国主要采用TACS和AMPS两种制式。第二代移动通信系统也有几种不同的制式,主要有欧洲的GSM和北美等国的DAMPS和CDMA等。目前我国广泛应用的是GSM系统。而CDMA也已在我国五个主要城市建网使用,并在逐步发展扩大其使用范围。 从移动通信技术发展的进程看、尽管     

移动通信系统中的切换技术

该文结合移动通信系统的发展,分析了第一代的AMPS、第二代的GSM、CDMA以及第三代的TD-SCDMA系统中的切换技术,探讨了未来移动通信切换技术的研究方向。     

从2代过渡到3代——TSM移动通信系统

介绍一种运行于GSM核心网络而以TD-SCDMA物理层为基础的系统：TSM系统。TSM系统提出的初衷一方面是为了解决以GSM作为第二代移动通信主要技术的运营商向第三代移动通信平滑过渡的问题；另一方面也是为TD-SCDMA系统的现状试验提供一个规范。TSM系统提出在GSM网络中，用TD-SCDMA技术提供第三代移动通信业务的概念和实现方法，此技术在GSM系统向第三代移动通信过渡的时期将有重要的现实意义。     

GSM/GPRS通信终端发射功率控制及校准方法

研究了GSM/GPRS系统中移动通信终端发射功率控制的必要性和原理及其移动通信终端功率控制的实现流程,在此基础上提出了曲线模拟和折线模拟两种方法,以实现移动通信终端发射功率校准,以及发射功率的精确控制,并对这两种方法进行了实际验证.验证结果表明采用基于这两种方法的校准都能较好地满足GSM/GPRS协议对移动通信终端发射功率的规定.并基于验证结果对它们各自的优缺点进行了分析、比较.还对前面提出的方法进行了推广,考虑了其在一般无线通信系统射频发射功率精确控制中的应用.     

3G时代电信运营市场的挑战与对策

3G是通信行业这几年讨论最热烈的话题之一。3G是Tiffrd Generation的缩写，特指第3代移动通信系统。目前中国移动使用的是GSM系统和中国联通的CDMA系统都是第2代移动通信系统，称之为2G。3G移动通信系统就是下一代的移动通信系统。传统的2G系统基本上只能提供普通的话音通话服务，而不能提供上网服务。目前移动的GPRS和联通的CDMA1X业务可以让人们通过手机上网，但速度不快。这种业务称为2．5G业务，就是从2G到3G的过渡业务。     

GPRS业务和话音业务能否同时使用的研究

GPRS(通用无线分组协议)是在现有的GSM(全球移动通信系统)网络基础上叠加的一个新网络,在使用GPRS上网时话音业务到底能否接入是用户比较关心的问题,从GPRS无线信道分配角度出发,探讨和研究了这个问题,并提出使用GPRS上网的同时可以使用话音业务的解决问题。     

爱立信脚踏两只船

在 CDMA 和 GSM/GPRS 系统的竞争中,爱立信的声势并不是很大,它既不像诺基亚那样认准 GSM/GPRS 不放,也不像摩托罗拉那样积极地参与中国联通共同建设CDMA 网络。它只能保持中立,它不能对这两个方面有任何偏向,因为无论在哪一个领域,它都是最大的提供商,至于 CDMA和 GSM/GPRS 将来哪一个能够在竞争中占优,都不会过多地影响到爱立信的收入     

国内科技

我移动通信技术获重大突破 国家“863”计划重大课题和原邮电部重点科技攻关项目CDMA移动通信交换分系统,由西安大唐电信有限公司研制开发获得成功,4月13日在天津通过了信息产业部组织的生产定型鉴定。这标志着我国在掌握第二代移动通信技术方面又取得了重大突破。 据介绍,CDMA和GSM同为第二代数字通信技术,目前我国移动通信中主要采用的仍是GSM技术。CDMA是利用宽带传输手段,在提高频谱利用     

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.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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