IMS的利与弊

电信运营商的战略转型给传统电信网络带来了极大的挑战。电信运营商现在关注的是成本控制、商务模式、技术/业务创新以及业务的市场导入期。这便要求传统垂直的业务网络向水平网络转移,能够快速、灵活地提供融合业务。IMS助运营商成功转型日前,法国电信北京研发中心举办了一场题为“核心网技术演进”的研讨会,中国移动研究院副院长王晓云在演讲指出,IMS实现接入技术、内容和应用的融合,能够帮助电信运营商成功转型。首先,使用IMS网络,运营商将能为用户提供丰富的应用。这些应用涉及终端设备和服务器,可以互相启动和调用,从而提供更丰富…     

美国法律关于互联互通的规定

网络互联和业务互通是公共电信运营商的基本义务之一。公共电信运营商应当直接或间接与其他电脑运营商的设施或设备实行网间互联，其所提供的网络在特性、功能和容量方面须符合法定标准。     

网络虚拟化技术在网络优化中的应用策略研究

随着移动互联时代的到来,对于电信运营商来说业务发展面临互联网的挑战,业务模式的改变必然导致网络重构和运营重构,未来网络功能以实现业务灵活提供、提高运营效率为目标。网络虚拟化技术可以使业务部署更敏捷,运维管理更简单,网络选择更自由从而为电信运营商带来新的发展空间。因此,在融入网络虚拟化技术使用的基础上,网络优化模式也随之改变,从而更好地支撑电信运营商的业务需求,进一步促进电信运营商的发展。     

IPTV的商业模式、运营模式及业务发展

IPTV作为一个新生事物，在市场运作方面受到了多方面因素的制约，需要在商业模式、运营模式和业务提供方式方面进行探索。可结合电信、广电以及互联网原有商业模式的优势，加以融合，形成产业价值链，实现各方合作共赢；可以根据发展阶段的不同，综合考虑技术实施及网络部署方案；可以通过合理的利润分配模式，推动IPTV业务的开展；可以通过业务捆绑提高市场竞争力，IPTV将为电信运营商战略转型提供切入点，满足电信运营商对业务创新的需求，将成为电信运营商在信息通信领域中探寻增长空间的一个亮点。     

新一代综合结算系统的设计与实现

随着中国的电信改革不断深入，多运营商、多业务互相渗透和竞争的格局已经初步建立。伴随电信行业垄断被打破，各电信企业间网络业务互联越来越普遍，结算业务收入在各电信运营公司的业务收入中占的比重也越来越大。同时伴随电信运营企业从粗放式到集约式经营管理思路的转变．电信企业也要求在不同区域。不同专业之间进行相关业务费用的摊分，实现成本核算。因此互联结算成为新形势下电信运营的关键问题之     

国外领先运营商网络IP化发展策略分析

目前,国内外电信运营商都在积极转型,而在转型过程中,网络的转型开始得最早,范围也最广.绝大多数的电信运营商都已经制订并实施了网络升级换代计划,期望通过网络的升级改造以更低的成本为用户提供丰富、灵活、个性化的业务.通过分析电信运营商的网络升级方案可以发现,其共同之处就是建设IP化的下一代网络,以统一的网络提供多种类型的业务,实现有线和无线之间以及语音、数据和视频业务之间的真正融合.     

移动支付:合作乃发展之道

目前,我国移动支付产业链核心成员包括电信运营商、金融机构以及第三方支付。根据向用户提供移动支付的主体不同,产业链模式可以分成三类:以电信运营商为主导的移动支付产业链模式,即运营商主导模式。在该模式中,电信运营商既是移动支付业务数据传输网络的提供者,又是移     

电信运营商对互联网电视业务的思考与实践

介绍了互联网电视业务发展的驱动力及互联网电视业务对电信运营商的机遇和挑战.探索了互联网电视业务的建设和商务模式.在电信运营商之间、电信运营商与互联网企业的视频业务竞争中,进一步思考,要努力做好以下几点：强化业务体验,有效占据用户家庭电视屏;创新商务模式,优化业务资费;改良业务内容和终端;充分发挥电信运营商的网络和计费优势;充分发挥电信运营商业务优势开展特色业务.     

服务电信IT企业10强

在20世纪80年代末、90年代初电信行业第一阶段网络基础设施的建设后，我国电信市场进入了第二轮信息化建设高潮，改变传统业务模式创新业务内容，建立开放业务平台等措施正有力地推动着电信运营商在现阶段市场环境中的自我转变和完善。     

浅谈面向ICT服务的电信网络架构及其技术实现

为使电信运营商实现ICT业务的拓展,对面向ICT服务的电信网络架构及其技术实现问题展开了分析。从分析结果来看,采用LSN电信网络架构,能够对传统ICT服务覆盖的所有区域范围进行覆盖,并为客户提供综合ICT服务,能够使电信运营商拓展ICT服务。而采用Vx LAN方式实现大二层互联,在数据通信中未出现数据丢失情况,并且能够为各种新型ICT应用场景的实现提供支持,因此能够为LSN架构实现提供支持。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its