TD-LTE与LTE FDD融合组网面临的挑战及建设策略

我国已发放TD-LTE商用网和LTE FDD实验网牌照,TD-LTE与LTE FDD融合组网已成为未来LTE网络建设的趋势。文章对比TD-LTE与LTE FDD网络的覆盖性能及容量性能,重点分析TD-LTE与LTE FDD融合组网过程中涉及的核心网融合建设、多制式网络协同定位及语音解决方案,并在此基础上,提出TD-LTE与LTE FDD融合组网的建设策略。     

TD-LTE与FDD LTE技术对比及融合组网策略分析

为了更好地满足移动用户的海量数据流量业务需求,TD-LTE和FDD LTE融合组网成为全球主流运营商的目标选择。本文从TD-LTE和FDD LTE物理层技术、频谱资源、覆盖性能等方面对比总结了两种制式的差异,并针对TDLTE和FDD LTE融合组网中的关键问题进行了深入分析,最后给出了TD-LTE和FDD LTE融合组网的策略建议,为运营商4G网络的规划和建设提供参考。     

LTE FDD与TD-LTE融合组网研究

分析了LTE FDD与TD-LTE之间的异同点,并且根据各自特点介绍了LTE FDD与TD-LTE融合组网的优点;通过性能对比详细介绍了融合组网技术,根据实际应用,提出了建设融合组网的策略建议,从而进一步保证LTE FDD与TD-LTE融合组网技术的应用更加稳定、高效。     

TD-LTE和LTE FDD融合组网研究

目前中国已经正式进入4G时代,网络部署节奏逐渐加快,LTE用户规模持续增长。如何能够从用户体验角度出发进行网络建设,兼顾多网络融合协调发展,最终实现网络投资效益最大化越来越受到运营商关注。其中TD-LTE和LTE FDD融合组网就是运营商、政府部门和产业界一直探讨的问题。通过LTE产业发展现状、国内频谱资源划分现状以及网络部署关键问题等多角度研究分析,并结合中国联通网络特点和演进需求,提出TD-LTE和LTE FDD融合组网方案以及具体部署建议。     

一个LTE还是两个LTE?

2013年是LTE发展史上极为关键的一年。GSA 8月发布的LTE演进报告显示,目前全球有443家运营商正在投资LTE,其中204张LTE网络已经开通商用服务。在204张商用网络中,20张为TD-LTE商用网络,其中约9家运营商选择了融合组网。虽然LTE FDD网络较TD-LTE发展早,但随着TD-LTE技术的成熟,运营商建设4G网络可选择其中一个制式的LTE;也可以选择搭建两个LTE,搭建TDD/FDD融合网络。     

TDD-FDD混合组网互操作策略优化和研究

随着用户对移动数据业务的需求不断增长,LTE FDD网络频率、容量等资源不足的问题逐渐凸显,而TD-LTE网络拥有更多的频谱资源,TD-LTE与LTE FDD融合组网可以有效缓解FDD频谱紧张、容量不足的问题,TD-LTE和LTE FDD相互融合并共同发展已成为未来全球移动通信产业的趋势。重点研究了不同场景下,通过参数调整选用不同的TDD/FDD互操作策略,给出该场景下最适合的互操作策略。     

专题导读

根据LTE产业链的发展状况及LTE使用频率的特点,当前大多数国际运营商仍集中精力发展LTE FDD移动网。从全球LTE网络的部署情况来看,截至2014年年底,在全球124个国家已经有360个LTE商用网络,其中LTE FDD网络329个,TD-LTE网络48个。另一方面,许多LTE运营商开始尝试选择混合组网,发挥TD-LTE和LTE FDD的各自优势,到目前已经有17个FDD/TDD混合网络。通过采用TD-LTE     

TD-LTE与LTE FDD混合组网策略研究

以TD-LTE与LTE FDD混合组网的趋势为切入口,立足于TD-LTE与LTE FDD混合组网技术及可行性方面,提出了关于TD-LTE与LTE FDD混合组网策略的几点看法,旨在促进TD-LTE与LTE FDD混合组网的实施,为我国未来实现更高层次的混合组网奠定基础。     

LT E混合组网的产业现状以及发展方向

TD-LTE和LTE FDD的融合发展被整个LTE产业链认为是LTE未来发展的必然趋势。结合LTE技术特点、国际上LTE网络部署状况,从多个方面论证了积极推动TD-LTE与LTE FDD混合组网对于我国未来实现LTE融合发展的重要意义。     

TD-LTE/LTE FDD融合组网关键技术

非常高兴和大家就TD-LTE和LTE FDD融合组网的技术进行探讨,其中包括两个方面内容,一是TDLTE和LTE FDD的组网部分,二是融合组网策略的影响因素。TD-LTE和FDD LTE融合组网之所以成为趋势,主要有以下两个方面的原因:一方面是,TD-LTE适合承载非对称业务,LTE FDD则适合对称业务,两者的融合可以更好地适应不同业务的发展需要,实现优势互补。另一方面是,可以使得整个的规     

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.     

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.     

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