固定无线接入系统对卫星地球站的干扰分析

为了使共用同一频段的3.5 GHz固定无线接入系统（FWA）和C波段固定卫星业务（FSS）实现共存,就需要对这两个系统间的干扰进行分析。采用确定性计算方法主要研究了在建筑物密集但排列比较整齐的地形中3.5 GHz固定无线接入系统对C波段卫星地球站产生的同频干扰,给出了同频干扰的计算方法,并进行了仿真分析,从而验证了在这种地形下实现两系统干扰共存的可行性。     

WLAN在电信及企业的应用尝试

1概述 目前人们所谈及的无线接入大多数是指固定无线接入,最近两年被看好的固定无线接入的热门体制有三种:即频段为3.5GHz的固定无线接入系统、频段为26GHz的本地多点分配业务系统和频段在2.4GHz的无线局域网、无线接入系统及蓝牙技术.由于2.4GHz频段的无线电台站,按照信息产业部发布的<微功率(短距离)无线电设备暂行规定>(信部[1998]178号)进行管理,即只要设备性能指标满足规定并取型号核准证,设台无需办理电台执照,这无疑给2.4GHz使用的普及奠定了良好的基础.     

3.5GHz频段固定无线接入系统网络规划技术研究

随着业务需求的日益增长,作为通信网络中重要组成部分的城域网得到了飞速发展,在接入网中部分采用甚至全部采用无线设备进行传输已经成为应用的热点。在固定无线接入系统中,3.5GHz频段作为国际电联(ITU)推荐使用并工作在低频段的点对多点无线通信技术的产品更引人关注,目前国外3.5GHz频段已开放2×100MHz频率资源,并已得到广泛使用。在我国,考虑到卫星通信的干扰问题,信息产业部无线电管理局于2000年正式开放2×31.5MHz频率资源用于固定无线接入,并于2001年9月颁布了《接入网技术要求——3.5GHz固定无线接入》技术规范,明确了3.5GHz固…     

3.5GHz频段LTE室内覆盖系统与卫星固定业务地球站同频共存分析

3.5GHz的频段规划需要研究LTE室内覆盖系统与卫星固定业务同频共存的场景。通过确定性分析以及系统仿真,本文给出了两系统共存所需的隔离距离和其他干扰规避措施建议。     

3.5 GHz固定无线接入市场令人关注

3.5GHz是国际电联推荐的用于固定无线接入的频段，系统构成一般包括基站、远端站和网管系统三大部分。3．5GHz固定无线接入可基于电路方式、IP方式、ATM方式等，提供的业务包括中高速因特网接入、局域网互连、VPN、租用线、IP电话／IP传真、视频会议、PSTN／ISDN等。中国2001年在5个城市首次进行了3.5GHz固定接入业务的招标，目前中标公司大都在提供业务。2002年年底信息产业部在32个城市再次进行3．5GHz频段的招标，激发了新一轮的竞争。     

LMDS技术及应用

1LMDS技术定义LMDS（LocalMultipointDistributionService，本地多点分配业务），一种微波宽带业务，工作在较高的射频频段（10~40GHz），最大可用频谱宽达1GHz，在较近的距离进行点对多点双向话音、视频、图像和其他数据业务的传输。定位为宽带固定无线接入系统，是一种被誉为     

马年话无线(Ⅱ)

六、无线接入不断升温无线接入是一个通称。从广义上无线接入可分为固定无线接入、移动无线接入；宽带接入、窄带接入；高速移动接入、低速移动接入等等。所以蜂窝移动通信、集群移动通信、无绳电话、蓝牙、以及现在俗称的“小灵通”等都可划入无线接入的范畴。但目前人们所谈及的无线接入多是指固定无线接入，最近一二年来被看好的无线接入的热门体制有三种：即频段为3.5GHz的固定无线接入系统、频段为26GHz的本地多点分配业务系统（LMDS）和频段在2.4GHz的蓝牙技术。当然从PHS派生过来的“小灵通”（PAS）也可属于热门之类。这里仅…     

中国宽带固定无线接入技术现状比较

目前，中国的宽带固定无线接入技术主要包括3.5GHz固定无线接入、公用频段5．8GHz和2.6GHz本地多点分配业务，芯片技术的进步使得设备集成度提高，也促进了设备调制效率的提高以及软件技术的发展，宽带固定无线接入设备的性价比显著增长。     

一种固定宽带无线接入系统中话音业务的动态接入技术

在简单介绍固定宽带无线接入系统之后 ,给出了一个 3.5GHz固定宽带无线接入系统中的MAC实现方案 ,着重研究了话音业务如何动态地接入骨干网 ;最后给出了话音业务通过E1接口接入PSTN的实现框图。本系统工作在 3.5GHz频段 ,采用FDD的双工技术、TDM/TDMA的复用多址技术、MAC技术实现了数据 /话音混合传送 ,并且通过动态资源分配保证了带宽的有效利用。     

中国铁通3.5G业务异军突起

3．5G业务给铁通带来新的发展机遇 近年来，随着电信市场的竞争加剧和通信技术的快速发展，各种本地接入方式不断涌现，其中采用无线传播方式的35GHz频段固定无线接入系统凭借其建设速度快、运营成本低、投资成本回收快等特点，已成为目前解决地区接入困难的一种较为理想的接入方式。2001年7月份，信息产业部在五个城市对35GHz频段频率进行第一次招标分配，从此揭开了中国35GHz频段地面固定无线接入系统的建设序幕。2002年12月，信息产业部在32个省会城市行政区域内，     

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.     

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     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first