基于集中式接入网架构的异构无线网络资源管理技术研究

未来无线通信网络将是一个多种无线接入方式共存的异构网络,如何实现异构网络在频谱、软硬件资源等方面的融合是一个亟需解决的问题.现有方案受限于不同网络独立部署的架构,无法真正实现异构网络资源的融合.针对该问题,提出了一种新型的基于集中式接入网架构的异构网络融合平台,可以在集中式资源池基础上进行异构网络间处理资源及无线资源的共享与统一管理.基于该平台,进一步阐述了异构网络资源管理的关键技术,包括基站资源虚拟化、处理资源按需分配、动态频谱共享、网络覆盖优化及性能分析验证方法等,为未来异构网络融合研究提供了一种可行的方案.     

基于软件定义的弹性智能边缘网络

提出了一种基于软件定义的弹性智能边缘网络架构,以实现对用户接入和数据接入的灵活调度和智能服务.通过软件定义的边缘设备弹性组网,使得网络具备服务无中断、能力虚拟化、控制集中化等特点,从而为运营商降低网络建设成本、提升服务质量以及增强安全管控能力提供了技术手段.     

一种新型的LTE-A网络切换认证协议

针对典型蜂窝网络LTE-A网络的切换认证问题,本文通过引入SDN（Software Defined Network,软件定义网络）,提出了软件定义LTE-A异构网络架构,在中心控制器中共享UE（User Equipment,用户设备）的安全上下文信息,以实现简化切换认证过程,提高认证效率的目标.中心控制器的加入,使蜂窝与核心网通信时需要增加一次信令开销,而LTE-A网络的标准切换认证方法过于复杂,应用在软件定义LTE-A异构网络中,会产生较多的信令开销.基于代理签名的切换认证方法,使UE在验证身份时不用经过核心网,减少了信令开销.在安全性相同的情况下,基于椭圆曲线的加密体系比基于RSA的加密体系计算量更小,有利于减少中心控制器的计算压力.本文采用椭圆曲线代理签名方法,提出了一种新型的切换认证协议,并运用着色Petri网进行建模和仿真分析.仿真结果表明,该协议是有效的,且安全性更高.     

基于干扰消除的异构蜂窝网络中断分析

在异构网络中,小小区可以为宏基站用户提供接入服务,并能够根据自身条件调节传输参数。该文研究在宏基站端干扰消除技术,来消除宏基站到小小区用户的干扰。该文分析了采用此种方案后异构网络下行链路的整体性能,推导了宏基站和小小区用户接收端信噪比的概率密度函数和分布函数。在此基础上,得到了系统整体中断概率的闭合表达式。理论推导和仿真结果表明,干扰消除方案能够有效提升异构蜂窝网络的整体性能。     

面向数字孪生城市的软件定义物联网架构

<正>泛在物联网感知是实现数字孪生城市的基础。本文从数字孪生城市物联网的泛在异构接入、弹性伸缩部署和灵活资源分配等需求出发,综合软件定义网络（SDN）控制层和数据层解耦的架构特点,提出一种面向数字孪生城市的软件定义物联网（SDIoT）架构,该架构分感知层、转发层、控制层、管理层和应用层,软件定义网络的三个平面与其技术优势得到保留,实现软件定义物联网和软件定义网络灵活共存,简化了物联网架构与管理方式,实现物联网资源的虚拟化和面向多业务服务需求的动态重构。数字孪生城市是智慧城市的一条新兴技术路径,     

统一用户数据库的分析和设计

统一用户档案（GUP）是3GPP定义的一种融合用户数据访问框架,它的基本出发点是以用户为中心,解决多种不同网络、业务的用户数据统一访问的问题。本文以3GPP的研究为基础,结合中国运营商网络的特点,对同一用户档案（GUP）在中国运营商网络中的落地进行了分析,提出了统一用户档案数据库（GUPP）的架构、数据定义,并对实现难点进行了剖析。     

一种新的下一代无线个人通信网络

下一代无线通信网络是以用户为中心和异构的,不仅支持网络的自动配置和适应性,而且使用扩展多跳的无线个域网(WPAN)。与此同时,它将以一种透明的方式向用户提供多种类型的服务,这就需要有效地把异构网络技术与不同类型的协议结合起来,形成一个完整的网络体系,网络整合的关键是通过IP技术来达到协议的整合。文中介绍一种新的适用于目前和未来无线个人通信及相关服务的无线个人通信网络架构及其关键技术。     

基于SDN与NFV的网络切片架构

传统网络架构面临着结构封闭僵化、数据传输转发性能高度受限以及资源利用率低等问题,使其不能满足未来多样化的服务需求。为了解决这个问题,引入了网络切片的概念,并将网络功能虚拟化（NFV）与软件定义网络（SDN）等前沿技术相互融合在一起,提出了一个面向未来移动通信的新型网络架构——基于SDN与NFV的网络切片架构。这种新的网络架构能够根据第三方需求来为用户提供个性化的网络服务,实现网络资源的共享和隔离,节省了运营商的在基础设备方面的大量花费。     

基于REST风格的混杂感知车载网信息服务设计

实时可靠地获得全面的车载感知服务信息是车载网络发展的"瓶颈"问题。混杂感知车载网(HSVN)兼有无线传感器网络(WSN)和车载自组网(VANET)的特点,为车载用户提供了大量车载信息,是车载网络的发展趋势。表述性状态转移(REST)架构统一了资源格式和交互形式,在服务器和客户端间进行无状态服务,有利于异构问题的解决。文章基于HSVN的信息服务特征,提出一种新型车载网络框架和服务模型,能提高车载感知信息的服务交互能力;基于REST架构理念,采用HSVN中信息服务资源设计方法,为异构网络下的信息交互系统提供一种轻量化的实现途径。     

基于实际城区场景的TD-LTE异构网络性能研究

本文对密集城区环境下的实际TD-LTE网络部署进行了研究.通过系统级仿真对宏小区/微小区、宏小区/家庭基站小区、宏小区/微小区/家庭基站小区3种异构网络的下行系统性能进行研究,并与单一宏小区的网络部署场景进行了比较.对实际城区环境下的信号传播损耗模型和用户分布进行了三维空间建模.通过比较4种不同TD-LTE网络部署方案下,位于不同楼层高度室内用户的性能,得出异构网络中不同小区(宏小区、微小区和家庭基站小区)的覆盖和容量特性.     

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.     

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.     

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.     

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.     

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.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.