5G网络上行覆盖增强研究

当前5G网络频段多为高频段，带宽资源丰富，但路径损耗、穿透损耗较高，上行覆盖相对较弱，如果引入低频段资源进行上行传输，高、低频载波协同有助于提升上行覆盖。结合频谱特性及行业现状，分析2.1 GHz和3.5 GHz等频段的链路预算和覆盖性能，比较上行覆盖增强的3种方案，并对载波聚合方案的优势和限制进行了具体分析，结果表明载波聚合方案是5G网络上行覆盖增强的优化解决方案。     

LTE FDD网络上行覆盖增强技术分析

在远距离覆盖场景下,由于LTE终端采用单天线发射模式,且最大发射功率较低,因而上行覆盖能力成为主要限制因素。分析了安装塔顶放大器和部署多天线2种上行覆盖增强技术,对其在LTE FDD宏基站和分布式基站方式下的覆盖增强效果进行了链路预算分析,用仿真验证2种技术对上行覆盖增强的有效性,并给出了LTE FDD上行覆盖增强建议。     

2.6GHz+700MHz频段5G上行增强方案研究

5G+垂直行业对网络的需求千差万别,中国移动5G主力频段有2.6GHz,但2.6GHz现阶段存在上行不足的问题,在移动与广电开展5G共建的背景下,引入700MHz实现上行增强。文章主要对R16版本中重新修订的SUL和CA两种上行增强方案在2.6GHz+700MHz协同组网中的应用进行研究,并对其性能进行对比分析,结果表明,两者在上行覆盖扩大上及时延降低上效果基本一致,在上行速率提升上,CA要优于SUL。但是由于SUL在技术和终端成熟度方面优于CA,在实际业务场景中可根据具体需求进行选择。     

5G无线网上行覆盖增强技术探讨

5G NR主流频段为3.5GHz(C-band),下行覆盖能力与4G LTE相当,但上行受终端天线数量和发射功率限制,覆盖能力有限,上下行覆盖严重不平衡。在阐述5G NR网络总体架构的基础上,详细分析了双连接(DC)、上下行解耦(SUL)、超级上行(Super UL)、下行载波聚合(DL CA)和上行载波聚合(UL CA)等上行覆盖增强技术的原理及特点,对比总结了各技术的优势与不足,并对上行覆盖增强技术的应用进行了展望。     

大唐移动TD-HSUPA更高传输速率改善用户体验

随着3GPP HSDPA标准化的完成,3G系统对下行分组数据业务的支持能力有了很大的增强。这自然就引发了～个考虑：HSDPA采用的关键技术是否可以应用于上行分组业务的优化,进而对覆盖、吞吐量以及时延等上行性能进行改善。于是,3GPP启动了针对HSUPA技术的研究,最早是建立了WCDMA上行增强可行性分析的研究项目。随后,TDD厂家也提出并建立了TDD止行增强研究项目,对基站快速调度、AMC、HARQ等技术进行评估。作为3GPP标准重要组成部分的TDSCDMA,也在HSUPA方面做了很多研究和评估工作。     

VoLTE增强技术综合部署方案研究及试验分析

随着5G网络建设的逐步推进,C网退频重耕对于低成本快速提升中国电信5G和4G网络的广覆盖和深度覆盖水平具有重要意义.因此,为承接C网全网语音业务,并为VoNR的适时引入做好准备,进一步提升VoLTE业务质量和客户感知十分必要.本文针对四个VoLTE增强关键技术的基本原理及其现网试验的测试结果进行了分析和研究,提出了VoLTE增强技术综合部署策略建议.     

NSA架构下上行智选功能验证

目前5G移动无线网络主流频率为3.5G。受限于3.5G传播能力和终端发射功率,相同工程参数的5G和4G基站,5G信号较4G的路径损耗更大。从而导致5G网络用户在中远点上行体验不佳。文章主要阐述了NSA(非独立组网)架构下5G网络的上行智选功能方案和验证效果。为了延伸5G上行、下行覆盖,改善边缘用户速率,某某运营商分别从技术思路、参数配置、案例实施等多方面进行分析验证,从而掌握其功能特点及开通方法和覆盖效果,为后续大规模应用打下良好基础。     

NSA架构语音解决方案及优化策略研究

NSA网络架构模式下，5G语音业务承载于4G锚点网络上。4/5G双连接模式的网络架构，使得终端语音业务上行功率较传统4G语音业务上行功率损失3dB，从而影响小区边缘NSA用户语音业务体验。本文研究了几种基于NSA终端上行功率分配的策略及其特点，以提升NSA终端上行覆盖性能和用户感知体验。     

基于用户感知的2.6G+700M+LTE立体组网

随着5G通信技术的快速发展和日趋成熟,基于用户业务感知的网络上下行业务提升对于无线通信网络优化分析越来越重要。在2.6G深度覆盖不足、4.9G尚未成熟部署的严峻背景下,在现网基础上构建起基于用户感知的2.6G+700M+LTE立体组网,最大化发挥各个频段的优势,是网络研究感知的重中之重。针对上行业务、下行业务和NR驻留感知三个重点问题,提出了2.6G+700M超级上行、NR频段间/频段内载波聚合、基于用户感知的5G驻留门限三个针对性策略,以达到提高网络质量、提升用户感知的目的。     

一种5G上行覆盖增强的方法

为了高效地利用5G多时隙重复发送特性来提升上行小包数据传输的覆盖性能，提出了一种无线基站根据上行无线传输环境以及上行无线信号质量等信息自动调整时隙重复次数的方法。基站先根据无线传输环境确定上行数据解调门限，并基于该解调门限的动态区间建立上行覆盖质量等级与时隙重复次数的映射关系表；再根据终端是否移动、终端所处无线连接状态、上行数据传输时的BLER以及终端报告的PHR信息等，自适应地调整上行覆盖质量等级即自动调整上行时隙重复次数，从而合理使用资源以实现小包数据传输时的上行覆盖性能提升。     

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.     

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.     

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.     

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.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

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.