TD-LTE系统EMM的介绍及其异常机制的研究

移动性管理(EMM,EPS Mobile Management)子层属于核心网非接入层,主要功能是支持用户无线终端的移动。介绍了EMM子层的一般过程,特殊过程和连接管理过程和状态划分,分析了EMM异常机制,并重点研究了附着过程中终端和网络端的异常情况以及相应的处理措施。     

LTE系统EMM一般过程的研究

EMM是LTE层3的一个子层,主要是支持一些用户设备的移动性功能。根据如何被初始化,EMM被划分为一般进程,特殊进程,连接移动性管理三个部分。其中一般过程是只有当非接入层信令存在时才被初始化的。通过对一般过程的描述,介绍EMM一般进程的功能以及实现过程。     

TD-LTE终端EMM实体一致性测试研究

EMM移动性管理是TD-LTE非接入层MM子层的一个实体,它主要提供用户的移动性管理,业务发起的连接性管理以及数据管理的特性。根据业务分域划分文章主要讨论支持PS（分组域）模式的EMM实体．一致性测试的具体实现方法,并通过一致性测试来验证EMM实体一般过程和特殊过程的功能。     

基于SDL的TD-LTE系统EMM子层协议测试

介绍了LTE协议栈架构和EMM子层功能,对移动性管理实体(MME,Mobile Management Entity)端的EMM子层协议进行模块化原语设计和状态跃迁分析。以终端开机附着到网络的过程为出发点,设计出附着过程的流程图。通过SDL状态机模拟信令仿真,从仿真图可以看出,按照3GPP LTE(Release 9)配置消息参数终端可以成功附着到网络,而终端非法或配置异常情况消息时会导致附着过程失败。     

基于TTCN-3的TD-LTE非接入层测试研究

主要在介绍TD-LTE非接入层协议和TTCN-3标准的基础上,对TD-LTE终端测试中E—UTRAN／SAE的系统架构和非接入层的测试模型进行分析,并使用TTCN-3对非接入层进行一致性测试,并以EMM实体为例进行了验证。证明了该方法能够有效实现EMM实体协议的一致性测试。     

TD-LTE网络端移动性管理实体测试研究

网络端非接入层具有核心网功能,演进型分组系统移动性管理(EMM)是非接入层移动性管理(MM)子层的一个重要实体,其主要提供移动性管理功能.一致性测试是高层通信协议软件的一种通用测试方法,其主要采用集仿真、开发和测试于一体的SDL and TTCN suite4.0软件作为开发工具,结合说明描述语言(SDL)和树表结合表示法(TTCN)的协仿真生成的消息序列表(MSC)来完成测试,从而达到错误追踪、修改错误代码及参数的目的.     

TD-SCDMA系统终端协议栈PDCP子层的研究

PDCP是TD-SCDMA系统中终端协议栈L2的一个子层,只适用于数据域(PS)。PDCP子层在用户数据传输过程中起着非常重要的作用,设计合理的PDCP子层将保证用户数据有效地进行传输。基于该目的,对PDCP在用户数据传输过程中进行研究,首先根据协议介绍PDCP子层的结构、功能描述和相关接口,然后主要设计PDCP子层在AM-RLC模式(RLC确认模式)下的数据传输过程的实现方法,包括PDCP链路建立、数据传输、链路释放过程。对PDCP子层的学习有一定的帮助。     

数字电视条件接收四层密钥系统研究与实现

本文简述了数字电视前端CA系统,在此基础上比较了三层和四层的密钥授权体系,对四层固定分组和四层动态分组的授权数据结构（EMM）做了详细的介绍。在百万级用户规模下对四层固定分组选用分组大小与用户授权管理数据的相关关系进行探讨,并基于原有的四层动态分组模型提出了由三四层密钥体系相结合的改进四层动态密钥体系的分配方法,最后通过实验条件实现四层动态加密系统。     

GPRS吞吐量性能分析

对GPRS无线接口上RLC/MAC子层的链路适配过程、RLC/MAC子层和LLC子层的ARQ性能、LLC子层上的吞吐量等问题进行了分析,提出了在RLC子层上基于BLER链路适配的方法,解析了在RLC/MAC子层上最佳的重传次数,并对多种影响GPRS无线网络吞吐量的因素进行了说明.     

EMM在CAS中的运行实践

主要阐述了数字电视前端CAS有关EMM数据流的运行实践,分析了两例EMM数据流故障原因,提出了解决问题的思路,以便更好地为广电客户服务。     

Electromagnetic missile launched from a uniform current sheet ofarbitrary shape

A time-domain method, referred to as the variable transformation method, is used to study the transient radiation field from a uniform current sheet of any shape. A uniform current sheet of arbitrary shape is found to be capable of launching an electromagnetic missile (EMM) over the area equal to that of the sheet. The authors first derive the time-domain expression of the transverse electric and magnetic field strength along the axis of a circular sheet. The EMM condition is then derived in the time-domain form. It is then proven that the EMM can exist over an area equal to that of the sheet in any shape     

Embedded metal mask enhanced evanescent near field optical lithography

Simulation of evanescent optical lithography using an embedded metal mask (EMM) shows that resolution and throughput are significantly enhanced over conventional ENFOL, due to coupling between surface plasmons and cavity mode excitations. The key role played by surface plasmon polaritons and the effects of wave vector matching between the incoming photon and the EMM mask grating are clear from the simulation. In particular a double peaked resonant intensity distribution is revealed for the first time within the dielectric filled mask cavity, for the shorter wavelengths only. This effect is highly conducive to efficient sub wavelength lithography and has not been discovered by previous simulations. The EMM–ENFOL process has considerable potential for cheap, high throughput nanolithography with resolution well below diffraction limits.     

Comment on “Electromagnetic missile launched from a uniformcurrent sheet of arbitrary shape”

For original paper, see Zhan and Wan (IEEE Trans. Electromagn. Compat. vol.33, no.1, p.61-3, Feb. 1991). Theoretical findings by Wu (1985) of some previously unexpected behaviors of the energy flux carried by a very-broad-band pulse makes it desirable to investigate the electromagnetic missile (EMM) launchers. Previously, current pulse distributions over a surface, or along a line, or a point source in certain reflecting or defracting systems, have been investigated. Some authors have begun to investigate an arbitrary current distribution for EMM launchers. The present authors think that this is possible directly. A circular current plate with a proper time characteristic has been found that can radiate an EMM. One may think of a current with a proper time characteristic of arbitrary shape, to be comprised of many circular current distributions whose radii are very small. Each circular current can generate an EMM on its center axis, thus a current of arbitrary shape is capable of launching an EMM over the area equal to that of the shape. Zhan and Wan tried to prove the idea in the time domain. The results show that it seems to be exact, but there is a problem in the process of the derivation. By discussing the problem, the present authors point out an additional conclusion that only a current with a proper time characteristic can generate an EMM     

Method for three-dimensional data registration from disparate imaging modalities in the NOGA Myocardial Viability Trial

Region-by-region comparison of data concerning left ventricular (LV) status is difficult to perform quantitatively if the data was acquired from disparate imaging modalities. We validated a method for comparing measurements obtained by electromechanical mapping (EMM) catheter with dobutamine stress echocardiography (DSE) via biplane contrast ventriculography, with the assistance of three-dimensional (3-D) echocardiographic data. The ventriculograms were traced and the borders were used to reconstruct the LV in 3-D with the aid of a database of 3-D echocardiographic studies. The 3-D LV was oriented to the EMM data based on the body coordinates and then manually scaled and translated to fit. The EMM data were mapped to the 3-D surface. The 3-D surface was divided into the 16 regions defined for echocardiographic assessment. The mean EMM value for local linear shortening, a parameter of function, was computed in each segment. The EMM and semiquantitative echocardiographic assessments of regional myocardial function were compared by segment, and the volume of the 3-D LV was compared with the volume computed from the ventriculogram. The volume of the 3-D surface correlated closely with that of the ventriculogram (r = 0.97, SEE = 27.4 ml) but with a significant overestimation of 63 +/- 35 ml. There was a highly significant (p < 0.0001) agreement in regional function between EMM and echo. Local linear shortening correlated significantly (p < 0.0001) with echocardiographic severity of wall motion, averaging 9.5 +/- 6.5, 8.1 +/- 5.4, 5.9 +/- 4.8, and 6.2 +/- 3.3 in segments read as normal, hypokinetic, akinetic, and dyskinetic, respectively. The method presented is valid for comparing cardiac parameters derived from disparate image data on a region-by-region basis by employing anatomic landmarks on 3-D reconstructions of the LV endocardial surface.     

针对DVB条件接收系统的攻击与防御策略研究

介绍了典型条件接收系统的工作原理,指出了条件接收系统受到的安全威胁主要是来自非授权用户对授权控制信息ECM和授权管理信息EMM的密码学攻击,综合分析了在实际DVB条件接收系统中生成ECM时使用较多的DES加密算法所受到各种攻击,以及生成EMM时使用较多的RSA加密算法所受到各种攻击,重点研究了针对RSA加密算法的计时攻击方法,并提出了针对各种主要加密算法攻击的防御和应对措施.     

Process characterization and optimization based on censored datafrom highly fractionated experiments

Censored data resulting from life-test of durable products, coupled with complicated structures of screening experiments, makes process characterization very difficult. Existing methods can be inadequate for modeling such data because important effects and factor levels might be identified wrongly. This article presents an expectation-modeling-maximization (EMM) algorithm, where censored data are imputed as pseudo-complete samples and a forward regression is used to compare all main effects and 2-factor interactions for process characterization. Then, the best combination of controllable variables is determined in order to optimize predictions from the final model. A sensitivity study of the selected models, with changes of imputation and parameter estimation methods, shows the importance of using appropriate models and estimation methods in EMM. The author's analysis of the Specht (1985) heat-exchanger life-test data indicates that E, EG, EH in the wall data and A, K, D, DJ in the corner data are the dominating factors. However, in finding the best process recipe, one might use a model with a few additional terms, which leads to more accurate predictions for better process optimization     

不锈钢表面光纤激光掩膜微细电解复合加工

为了实现不锈钢微细电解定域加工,提出激光掩膜表面改性微细电解复合加工技术。研发了激光掩膜微细电解复合加工装置,并进行样件加工试验。首先,采用光纤激光在304不锈钢表面扫描加热进行打标图案,利用X射线光电子能谱分析(XPS)对不锈钢表面激光打标图案进行分析,发现激光在不锈钢表面打标时被空气氧化生成铁、铬等氧化物,生成的打标图案具有耐腐蚀性,形成保护性掩膜。然后进行电解加工,由于掩膜图案在电解过程中起到保护作用,选择合适的电解加工参数,在不锈钢表面能加工复杂的微结构。最后利用SEM、光学轮廓仪来观测微结构形貌、粗糙度等。研究结果表明:利用激光表面改性,结合微细电解加工能实现304不锈钢微结构的快速加工,该工艺在微细加工领域具有很好的发展前景。     

针对高速交换结构的广义极大匹配调度算法

调度算法是决定交换结构性能和实现复杂度的重要因素,极大匹配算法在这两方面存在不足.本文提出一类广义极大匹配(EMM)算法,使用不同权值参数能够派生出不同子类的算法.对广义极大匹配算法的研究从两方面展开,首先在2倍数据加速比下证明任何EMM(2)算法都能取得100％的吞吐量,并通过仿真表明能够取得与理想输出排队相近的延时性能;其次在没有加速比的条件下通过仿真表明具有2个以上权值参数的广义极大匹配算法能够大大提高极大匹配算法的吞吐量性能.