第四代移动通信露曙光

本文介绍了第四代（4G）移动通信的概念和技术要求，着重讨论了正交频分复用（OFDM）在第四代移动通信中的应用，最后简要的介绍了第四代移动通信的研发状况。     

第四代移动通信中的OFDM技术

在对比第三代移动通信(3G)和第四代移动通信(4G)特点的基础上,对OFDM技术的特点、基本原理和关键技术等作了论述,并指出OFDM技术将是未来4G系统的核心技术。     

第四代移动通信系统

本从基本概念，接系统，关键技术等几个方面全面介绍了第四代移动通信系统，并简单介绍了OFDM技术在第四代移动通信中的应用。     

OFDM技术研究

正交频分复用是第四代移动通信的核心技术之一,文章阐述了OFDM技术的发展过程,介绍了OFDM系统的基本原理;根据OFDM技术的实际运用,讨论了系统的优缺点并提出了目前OFDM系统的关键技术。     

OFDM-第四代移动通信核心技术分析

OFDM是正交频分复用的第四代移动通信核心技术,也是无线多媒体在实现通信过程中的关键技术。文章主要介绍了OFDM系统的相关技术,包括基本的信道估计方法、典型的估计方法和计算机仿真技术,对这种第四代移动通信核心技术进行了全面的分析。     

分析第四代移动通信技术(4G)的关键技术

以第四代移动通信技术作为切入点,分别介绍了OFDM正交频分复用技术、无线定位技术、以及IPv6协议技术的基本概念、特点、以及应用价值,指出了以上技术在第四代移动通信领域中的应用价值。     

4G中的MIMO-OFDM原理及关键技术

本文介绍了4G移动通信中的OFDM技术、MIMO技术的基本原理及MIMO—OFDM系统的关键技术。MIMO技术与OFDM技术结合，成为4G移动通信中有效对抗频率选择性衰落、提高数据传输速率、增大系统容量的关键技术，是第四代移动通信系统研究的热点问题。     

OFDM技术标准化展望

本文主要介绍了OFDM的原理和技术优势,分析了现存的几种类型的OFDM技术特点,最后展望了OFDM标准化和在第四代移动通信系统的应用.     

第四代移动通信的发展与挑战

对第四代移动通信系统（4^th Generation Mobile Communication，4G）的起源、发展、特点，及世界上一些主要国家的研究进展作了介绍，并讨论了第四代移动通信系统可能涉及的几种核心技术：OFDM、软件无线电以及智能天线技术，最后提出了第四代移动通信系统空中接口在多址方式上将面临的挑战。     

OFDM技术在无线局域网中的应用研究及最新发展

本文全面详述了第四代移动通信的关键技术0FDM及其特点，分析了OFDM技术在无线局域网中的应用，探讨了OFDM最新发展MIMO OFDM技术及其在下一代无线局域网标准：IEEE802．11n。     

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.     

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 rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks