发展3G的时间窗口问题

此次电信重组后,三大电信运营商都将得到3G移动通信许可证,我国3G移动通信将进入快速发展的轨道.同时,三大运营商都宣称今后将演进到LTE,LTE作为的3,9G的出现使得3G的演进不平滑.LTE和3G(WCDMA/TDSCDMA,下同)采用不同的空中接口,从3G演进到LTE需要更换基站和手机.     

LTE回传方案多样 运营商可因地制宜

LTE将是今后全球最主要的广域宽带移动通信系统,未来所有的2G/3G/3.5G技术都将殊途同归,统一演进到LTE/LTE-A阶段。但由于各国运营商2G/3G网络发展情况不同,对于LTE的演进路线也是形态各异。     

3G移动通信发展回顾及LTE与LTE—A演进策略展望

文章回顾了中国3G移动通信发展历程，分别对三大电信运营商的3G发展状况进行了逐一点评，分析各自在全业务运营中面临的现实挑战，并对LTE／LTE—A演进策略予以展望。     

登上3G的顶上台阶HSPA＋逾越LTE直奔4G

编者按：2008年至今,陆续有各国重量级电信运营商正在或计划将网络升级到HSPA＋,目前已有86＋国家共计198个运营商推出HSPA商业服务,用户超过5000万。中国电信今夏将全国部署3．5G的EV—DORev．A网络,中国联通已在部分城市部署WCDMA的最高版本R6,升级到HSPA乃至HSPA＋似乎指日可待,中国移动TD网络已全部升级到HSDPA,有消息称年底将升级到HSUPA。中国三大运营商部署的3G网络都将处于3G—LTE演进阶段的RSPA或相当于HSPA的BV—DORev．A／EV-DORev．B阶段,而LTE的商用又似乎呼之欲出……中国电信运营商是遵循3G演进规律,按部就班地从3G—HSPA—HSPA＋-LTE,还是在现有的HSPA阶段一心等待LTE成熟时一步到位LTE？前者似乎无视LTE的快速进展,和用户越来越高的速率要求;后者需要巨额的网络升级成本,且会造成巨大资源浪费。HSPA＋能超越吗？中国运营商应该如何迎接LTE时代？对于我国自主创新的TD—SCDMA,因为尚无可资借鉴的经验和教训,这样的争论和讨论更是弥足珍贵。     

加入“3G论坛”，共话3G未来

我国正处于第三代移动通信技术商用前夕,面对移动通信的庞大市场,有关3G标准的斗争愈演愈烈,各种标准的发展前景变幻莫测。如何对日新月异的移动新技术做出明智的抉择,在日益激烈的竞争中立于不败之地,是每个通信运营商和设备制造商所面临的重大战略课题。中国联通CDMA项目的启动,标志着3种3G技术标准在中国的3足鼎力之势有望确立。中国是世界第一大移动通信市场,因此,中国的3G技术格局将对全球的格局产生深远的影响,中国将选择何种3G技术?3G牌照将怎么发?这些都是全球关注的焦点。不久,中国的3G试验将开始启动,非常需要一个能沟通政府、运营商、制造商和其它关心中国3G发展人士的桥梁。     

3G网络规划建设浅议

2009年1月7日，工业和信息化部根据国务院会议精神，正式将3G移动通信运营牌照发放给中国电信、中国移动和中国联通三家基础电信运营商，并正式分配3G频段；随后各大运营商宣布将于今年“5·17”世界电信日起，正式推出丰富多彩的3G服务。自此，中国的移动通信全面跨入了3G时代。     

庾志成：3G依然是不可跨越的阶段

在很多国家和地区已经实现规模商用的3G,其发展依然面临问题——运营商究竟怎样靠3G大幅度提升利润？能否跨过3G直接发展LTE？哪些3G应用才是运营商收入的增长点？近日,《世界电信》（以下简称“WT”）邀请信息产业部电信研究院通信信息研究所副总工庾志成,对全球3G市场及发展进行了分析。庾志成表示,2008年,随着用户和网络规模不断扩大。全球移动通信行业已经全面进入3G时代。3G依然是不可跨越的阶段。其特色业务将成为推动移动运营商增加收入的主要驱动力。     

中国联通：3G启动力拔先机

目前，我国电信运营市场已经形成以中国电信、中国移动、中国联通、中国网通等四大运营商为主的格局，但移动运营商只有中国移动、中国联通。从电信改革的趋势来看，伴随3G牌照发放启动，现有四大电信运营商将逐步形成未来四大全业务运营商。随着移动通信的飞速发展，在国     

日本3G用户市场发展状况分析

在3G三大标准W-CDMA．CDMA2000与TD-SCDMA之争中．以前两项标准的商用化进展最快．而日本是目前全球唯一同时拥有W-CDMA及CDMA2000两项商用服务的国家，日本的三大电信运营商NTTDoCoMo(采用W-CDMA标准)．KDDI(采用CDMA2000标准)和J-Phone(采用W-CDMA标准)都已经推出了自己的3G移动通信业务。截至2003年3月底．这三家电信运营商的3G用户数分别为33万．680．5万及2．5万户，整个日本3G市场的用户数合计为716万户．这一数字已经超过了日本全国移动电话用户总数的9％。     

与其奢谈3G,不如研究应用

3G热潮席卷中国,涉足其中的中国电信运营商无疑是扮演搅起这潭浑水的主角。虽然信息产业部到现在关于3G牌照的问题还未有正式的说法,但深陷其中的电信运营商表露出来的热情让人咋舌,研究3G的专家和咨询公司成为运营商的座上客,似乎只要3G网络一建设．3G业务一开展,电信运营商的利润便会因此而大幅增长。     

GEMNET: a generalized, shuffle-exchange-based, regular, scalable,modular, multihop, WDM lightwave network

GEMNET is a generalization of shuffle-exchange networks and it can represent a family of network structures (including ShuffleNet and de Bruijn graph) for an arbitrary number of nodes. GEMNET employs a regular interconnection graph with highly desirable properties such as small nodal degree, simple routing, small diameter, and growth capability (viz. scalability). GEMNET can serve as a logical (virtual), packet-switched, multihop topology which can be employed for constructing the next generation of lightwave networks using wavelength-division multiplexing (WDM). Various properties of GEMNET are studied     

Thermodynamics of copper matte converting: Part III. Steady-state volatilization of Au,Ag, Pb,Zn, Ni,Se, Te,Bi, Sb,and As from slag,matte, and metallic copper

A comprehensive compilation of various thermodynamic data required for a complete analysis of copper matte converting reactions is presented. The data comprise estimated free energies of formation for such gases as SeO, SeS, TeO, TeS, BiO, BiS, SbO, SbS, AsO, and AsS, as well as activity coefficients in dilute copper alloys and vapor pressures of various elements and compounds. The volatilization of minor elements in steady-state reactors comprising gas and several condensed phases is mathematically formulated, and a parameter which governs the volatilization in such reactors is defined and named volatilization constant. The vapor pressures of various volatile species are calculated thermodynamically for the Noranda Process reactor by assuming equilibrium conditions. The volatilization constants of various minor elements are expressed explicitly as functions of oxygen and sulfur activities. Formerly Associate Professor, Department of Metallurgical Engineering, University of Utah, Salt Lake City, UT     

Bits, symbols, bauds, and bandwidth

The use of clear, concise, and unambiguous language in telecommunications engineering is vital to communicate a desired meaning and understanding. Terminology should be based on rigorous engineering principles and traceable to well known and dependable sources. This article deals with four everyday terms commonly encountered in the popular semi-technical press as well as in serious engineering periodicals. The misuse of these and other terms can lead to low-balled cost proposals, court litigation, and patent infringement cases. Imagine how an engineering student can be confused when she/he typically encounters bandwidth measured in bits per second     

Novel planar, square-shaped, dielectric-waveguide, single-, and dual-mode filters

This paper presents a novel concept of a square-shaped dielectric-waveguide resonator, which can easily realize a dielectric-waveguide cross-coupled filter or a dielectric-waveguide dual-mode filter, using the conventional printed circuit board (PCB) process. This planar dielectric-waveguide resonator has a higher Q value than a microstrip resonator. The physical mechanisms of both single- and dual-mode filters are elucidated. Some new coupling structures are developed for undergoing the PCB process. Filter design procedures are detailed. Design curves for the coupling coefficients of internal- and external-coupling structures are determined by full-wave finite-element-method electromagnetic calculations. Measurement results are highly consistent with theory for all trial filters. This study offers an effective means of producing low-cost high-performance planar circuit filters.     

PBX技术.市态.营销.选购

本文介绍了ＰＢＸ交换机的技术及市场需求态势。并提出ＰＢＸ产品的营销要素及其用户在选购时应遵循的原则。     

Dilemmas,uncertainty, risks,and board performance

This paper traces the origins of the words risk, uncertainty, governance and development and argues that a deeper understanding of each allows more effective decision taking in the boardroom. It argues that the role of the board of directors is to balance and rebalance continuously their irresolvable dilemma — ‘how do we drive our enterprise forward while keeping it under prudent control?’ It argues that it is the board’s role to focus on uncertainty, rather than risk, and this requires a different set of intellectual skills from board members to be able to cope with monitoring a range of diverse scenarios. This is crucial for a board to develop stronger ways of both leading their organisation and of ensuring the connectedness of the learning within and between the board and the operational unit’s risk taking. It advocates that to achieve this a board must develop new ways of learning — especially of thinking strategically and becoming more sensitised to the dynamics of their changing external environments. This will take them well beyond the comforts of their specialist managerial disciplines and into the true world of directing. The paper demonstrates the importance of continuous learning in reducing organisational uncertainty and risk. It uses the ‘Learning Board’ process and model as the central processor of both strategic and operational learning to create an annual rhythm for the board’s year.