TD-SCDMA系统容量分析

中国提出的第三代移动通信系统（ＴＤ－ＳＣＤＭＡ），采用了智能天线技术，大大提高了系统容量。本文在基于非理想功率控制和非理想波束的情况下，对ＴＤ－ＳＣＤＭＡ系统的容量进行理论分析。     

TD_SCDMA中的信道编码

ＴＤ_ＳＣＤＭＡ是由我国提出的第三代移动通信标准方案．于１９９９年１１月被国际电信联盟（ＩＴＵ）接纳为第三代移动通信无线接口技术规范之一。２００１年３月,又被３ＧＰＰ正式接纳,并包含在 ３ＧＰＰ版本４（Ｒｅｌｅａｓｅ ４）中。这标志着ＴＤ－ＳＣＤＭＡ继被ＦＹＵ正式确定为３Ｇ标准后,又被全球电信运营商和设备制造商所接受。由此,ＴＤ－ＳＣＤＭＡ技术真正成为全球第三代移动通信网络建设的选择方案之一。 信道编码ＲＴＤ＿ＳＣＤＭＡ系统中一个十分重要的环节。在３Ｇ标准里,对其做了十分详细的规定和说明。按照３Ｇ标…     

TDD模式与第三代移动通信系统

时分双工（ＴＤＤ）是一种通信系统的双工方式,在移动通信系统中用于分离接收和传送仆道。移动通信目前正向第三代发展,中国于１９９７年６月提交了第三代移动通信标准草案（ＴＤ－ＳＣＤＭＡ）,其ＴＤＤ模式及智能天线新技术等特色受到高度评价并成三个主要候选标准之一。在第一代和第二代移动系统中ＦＤＤ模式一统天下,ＴＤＤ模式没有引导起重视。但由于新业务的需要和新技术的发展,以及ＴＤＤ模式的许多优势,ＴＤＤ模式将日     

TD—SCDMA移动通信系统特点分析

国际无线电咨询委员会为下一代移动通信系统制定的技术标准为ＩＭＴ－２０００,其含义是：在２０００年后使用,工作于２０００ＭＨｚ频带,最高数据传输速率为２０００ｋｂｉｔ／ｓ。目前经国际电信联盟（ＩＴＵ）认可的３Ｇ无线传输技术共有３种标准,分别是Ｗ－ＣＤＭＡ、ＣＤＭＡ－２２０及 ＴＤ－ＳＣＤＭＡ。其中 ＴＤ－ＳＣＤＭＡ（时分同步码分多址）标准由中国提出。 在第三代移动通信技术中,ＴＤＤ模式的无线传输技术在频谱灵活性、提供不对称业务和低价格等方面的优势已被国际上认可。根据我国提出的ＴＤ－ＳＣＤＭＡ技术标准…     

第三代移动通信系统和中国提案

本文阐述第三代移动通信系统（３Ｇ）的主要目标和特性，以及国际上关于３Ｇ工作的当前进展，对中国的３Ｇ传输技术提案ＴＤ－ＳＣＤＭＡ做了重点介绍。     

风景这边独好——大唐电信移动通信前行的足迹

在我国移动通信技术及设备研发领域，大唐电信扮演着十分重要的角色，从ＧＳＭ到ＣＤＭＡ，再到ＴＤ－ＳＣＤＭＡ，每个领域都可以看到大唐电信的名字，多年来，大唐人高举“作民族信息产业脊梁”的旗帜，一路风风雨雨走过，留下了一串串艰难而难以磨灭的足迹。ＴＤ－ＳＣＤＭＡ：中国提出的世界标准 目前，第三代移动通信系统已成为未来的发展趋势。由于在第一代、第二代移动通信标准制定上中国没有能力及时参与，从而导致国内设备开发工作的滞后，跟不上通信事业发展的需要，不得不花费大量的外汇从国外引进设备，影响了我国移动通信产业…     

中国的3G技术——TD—SCDMA

近年来,第三代移动通信一直是人们关注的热点。而我国提出的ＴＤ－ＳＣＤＭＡ(时分同步码分多址)无线传输技术现已作为中国提出的第三代移动通信标准,被国际电信联盟接纳为第三代移动通信标准之一,与欧洲支持的ＷＣＤＭＡ和美国的ｃｄｍａ２０００成为未来全球第三代移动通信标准的３个最主要的竞争者。     

第三代移动通信和中国的TD—SCDMA

介绍第三代移动通信和我国ＴＤ－ＳＣＤＭＡ的技术、特点和标准化工作进程,以及有关基站、终端等方面的情况。     

第三代移动通信之发展

本在简述了第三代移动通信标准概况和世界第三代移动通信发展主要现状的基础上，着重介绍了ＴＤ－ＳＣＤＭＡ技术；比较了ＦＤＤ和ＴＤＤ两种模式，指出ＴＤＤ与ＦＤＤ两种模式有着相副互无法取代的优点。     

TD-SCDMA在3GPP组织的国际标准化工作中的作用

众所周知,ＴＤ－ＳＣＤＭＡ是一个由中国和欧洲的公司共同推动并正在开发的一种第三代移动通信技术,它特别适合中国市场对第三代移动通信服务的需求。目前,这一技术已经被国际电联（ＩＴＵ）正式采纳成为第三代移动通信国际标准──ＩＭＴ－２０００家族的一员,并且被公认为能够全面支持第三代业务的技术。这一技术已经引起了多方的关注,同时,由于ＩＭＴ－２０００中包含ＴＤ－ＳＣＤＭＡ技术,因此,在第三代协作项目组织（３ＧＰＰ）内部正在加紧进行标准融合的工作,以促进第三代移动通信标准的发展,这一点,使ＴＤ－ＳＣＤＭＡ更进一步地受到国际社会的关注。 实际上,人们很早便开始了对第三代移动通信系统的研究。１９９８年１月,欧洲标准化组织──欧洲通信标准协会特别移动部（ＥＴＳＩ ＳＭＧ）采纳了一项关于第三代移动通信系统的空中接口提案,这一提案被命名为全球移动通信系统,即人们现在常说的ＵＭＴＳ。ＵＭＴＳ陆地无线接入（ＵＴＲＡ）包括了两种模式,频分双工模式（ＦＤＤ）和时分双工模式（ＴＤＤ）。 前者采用的技术为ＷＣＤＭＡ,后者采用的技术为ＴＤ－ＣＤＭＡ。 在欧洲开发ＵＭＴＳ标准的时候,日本也对第三代移动通信系统进行了广泛的研究。日本的标准化组织──...     

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.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

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.