无线城域网（WMAN）下两种接入技术的分析比较

当前,WiMAX技术和McWiLL技术已经成为无线城域网下接入技术研究的热点。首先简要介绍了WiMAX技术和McWiLL技术的发展及现状,分别分析了两类接入技术的网络架构,重点研究了两种技术在组网方面的不同,提出了每类技术对应的组网方式,并最后分析了WiMAX技术和McWiLL技术与现有3G网络的融合组网方案以及两种WiMAX与WCDMA网络融合方案的优缺点。     

TD-SCDMA与WCDMA混合组网的网络规划研究

3G网络商用方案在逐步敲定的过程中,对于网络规划的要求也就越来越高.在中国目前的电信形势下,WCDMA与TD-SCDMA混合组网的方案也得到更多的重视.本文从网络规划的角度阐述了TD-SCDMA与WCDMA混合组网方案的具体内容与可行性.     

TD—SCDMA与WiMAX联合组网方案的研究

TD-SCDMA和WiMAX联合组网可以有效发挥各自优势,规避各自劣势,为用户提供更高质量的多媒体业务.文章从市场、网络建设和技术三方面的互补性分析了二者联合组网的基础,提出了联合组网的技术方案,阐述了未来TD-SCDMA与WiMAX网络融合和演进的四个步骤.     

广电接入网的混合组网模式

随着互联网的快速发展，国内广电运营商的网络已经难以支撑高速数据业务，向FTTH升级是多数运营商都已经达成的共识。但网络升级难以一步到位，这可能是一个长期的过程，在这个过程中将会出现多种接入网技术体系并存的情况，也就是混合组网，如何选择混合组网的技术体系是一个值得深入研讨的课题。     

TD-SCDMA与WCDMA混合组网的网络规划方案

3G网络商用方案在逐步敲定的过程中，对于网络规划的要求也就越来越高。在中国特有的国情下，WCDMA与TD-SCDMA混合组网的方案也渐渐浮出水面。文章从网络规划的角度阐述了TD-SCDMA与WCDMA混合组网方案的具体内容与可行性。     

WiMAX无线组网分析

WiMAX（全球微波互联接入）无线蜂窝组网作为OFDM（正交频分复用）技术在蜂窝网络中的第一次大规模应用，如何解决覆盖是WiMAX系统组网面临的首要问题。时分双工方式下的WiMAX系统在覆盖上面临两个主要问题：一是高频段带来的高路损；二是时分双工方式带来的噪声系数提升以及编码方式低冗余。     

WiMAX系统部署研究

作为一种宽带无线解决方案,WiMAX系统的覆盖范囤大,且无须耗资建设昂贵的有线设施.与有线网络相比,它具有成本高效和部署迅速等优势.给出了WiMAX系统的部署模型,介绍了WiMAX系统的组网结构,列举了WiMAX系统的部署场景,分析了WiMAX系统的网络配置.     

GSM与WCDMA混合组网策略研究

对GSM和WCDMA网络进行混合组网是移动通信网络的必经阶段,混合组网时所执行的组网策略的优劣直接决定着移动通信网络的服务质量和后续发展。文章对两种网络制式的核心网网元结构融合进行了研究,之后对混合网络的组网策略进行了详细分析和讨论。     

宽带无线接入WiMAX系统组网设计

WiMAX作为新兴的宽带无线接入技术,具有覆盖范围广、传输带宽大的特点,已经成为电信业关注的热点,WiMAX无线接入系统的组网设计问题已成为一个重要的课题.文中对WiMAX组网设计涉及到的几个关键问题,如业务需求预测、频率规划、传播摸型、组网方式等相关问题进行了探讨,可为WiMAX无线接入网络的规划,工程设计和工程建设提供参考和帮助.     

TD-SCDMA/GSM混合组网分析

TD—SCDMA与GSM混合组网方案能够实现在城区的热点地区提供3G服务．同时利用现有的2G网络提供补充性的全覆盖服务．是一种可行的组网方案。计时TD—SCDMA／GSM的混合组网进行了初步的分析．指出混合组网的优势所在．然后分别给出了对于TD—SCDMA／GSM混合组网中的组网技术、互操作与终端问题的建议。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.