宽带卫星通信发展概况与前景展望

首先对宽带卫星通信系统的类型和技术优势进行了分析,然后介绍了宽带卫星通信技术在国内外的发展现状,最后对宽带卫星通信在发展过程中存在的问题及面临的挑战进行了讨论,并对其发展前景进行了展望。     

基于卫星和集群通信的渔船组网技术与应用

渔业公司船多且作业队伍不固定,通过在每艘船上加装卫星通信终端来解决远洋宽带通信问题成本很高。根据船队分为指挥船与任务船两类,出海作业时每组由一艘指挥船带领若干任务船的特点,在指挥中心和指挥船之间建立卫星通信网络,在指挥船和任务船之间建立移动宽带多媒体通信网络,并辅以组播、路由自动切换等策略。建成后的系统可实现任意船只之间以及船与指挥中心间的宽带互联互通,指挥船与任务船随机组队时,链路可自适应,系统无需重新配置,指挥船与任务船间宽带通信距离大于20 km。该系统可大大降低渔业公司远洋宽带通信网络的建设成本与运营成本。     

卫星通信技术的新发展

就当前卫星通信技术的若干热点作了一些概括和综述。首先,介绍了宽带卫星通信系统的有关概念和发展现状,提出了需解决的主要技术问题,给出了典型应用;然后,在介绍卫星移动通信的国内外发展现状的基础上,研究了系统的特点及需要突破的关键技术;最后,介绍了空间通信网的基本概念,给出了网络组成及功能,分析了需要解决的若干新技术。     

宽带卫星通信系统分析与技术展望

详细探讨了宽带卫星通信的发展概况、设计原则、问题和折衷考虑,提出了宽带卫星通信网络的结构模型以及卫星星座设计选择,讨论并分析了宽带卫星通信的若干关键技术以及发展所面临的问题,最后阐述了宽带卫星通信技术的未来发展趋势。     

具有星际链路的LEO&MEO双层卫星网络路由策略研究

本文提出了一个具有星际链路的LEO&MEO(低轨和中轨 )双层卫星通信系统 ,详细介绍了系统结构、协议体系并重点研究了双层卫星系统的路由问题 .为了适应宽带多媒体通信的需要 ,系统采用了ATM快速分组交换技术 .提出了基于Dijkstra算法的双层卫星网络时延最短路由策略和时延抖动最小路由策略 ,并通过计算机仿真研究了它们的性能 ,得到了具有一定参考价值的结果 .     

一种适合宽带多媒体卫星通信系统的异步突发时间计划生成方法

 在宽带多媒体卫星通信系统带宽按需分配(Bandwidth on Demand,BoD)过程中,采用周期性突发时间计划生成(Periodical Burst Time Plan Generation,P-BTPG)方法会导致BoD性能对带宽分配周期和带宽分配时延十分敏感.通过建立BoD时序模型,推导最优带宽分配周期和分配时延值,给出一种最优的突发时间计划生成(Optimal Burst Time Plan Generation,O-BTPG)方法.针对该方法导致突发时间计划(Burst Time Plan BTP)信令开销过大的问题,进一步提出一种能够根据带宽需求异步生成突发时间计划(Asynchronous Burst Time Plan Generation,A-BTPG)的方法,推导采用该方法的最优带宽分配长度和最优带宽分配时刻表达式,给出该方法的执行流程;采用两种典型带宽分配算法对不同的BTP生成方法进行性能仿真与分析,仿真结果表明:A-BTPG方法具有较好的通用性,在控制BTP信令开销的前提下能够明显提升系统带宽动态响应能力.     

COMETS experiments for advanced mobile satellite communications and advanced satellite broadcasting

The Communications and Broadcasting Engineering Test Satellite (COMETS) was developed to evaluate Ka‐band (31/21GHz) and millimetre‐wave (47/44 GHz) advanced mobile satellite communications systems, 21GHz advanced satellite broadcasting systems, and S‐band and Ka‐band inter‐orbit satellite communications systems. COMETS was launched because it was to become the new ‘bridge’ toward advanced satellite communications technologies in the next century, but the launch on 21 February 1998 regretfully failed due to premature shut down of the second stage engine of the H‐II launch rocket. After this accident, the initial low elliptic orbit of COMETS was improved by the apogee engine to a larger elliptic orbit with an apogee altitude of 17711km, a perigee altitude of 473 km, an inclination of 30.1°, and an orbital period of 319 min. Original and modified COMETS experimental plans, countermeasures in earth stations for the orbiting satellite, as well as an overview of the COMETS satellite and ground terminals are presented. Copyright © 2000 John Wiley & Sons, Ltd.     

现代通信与信息技术在海事通信中的应用展望

在现代航海事业中,安全可靠的通信技术是船舶安全航行和海上生命安全的重要保障,具有重要的研究意义.为此,介绍了现代网络技术、新一代卫星通信系统、数字海洋技术及新一代宽带无线移动通信技术等现代通信与信息技术的发展现状,分析了其在海事通信中的应用,并就有关应用中存在的一些问题进行了探讨.     

基于DVB-RCS的VSAT宽带卫星通信技术与应用

介绍了VSAT数据网原理、卫星通信系统宽带化的发展趋势及DVB-RCS开放标准。通过介绍基于DVB-RCS的VSAT宽带卫星通信系统在工程中的应用实例,其中包括系统业务与特点,以及各子系统的基本配置等,可以得出,随着网络和业务的宽带化,VSAT卫星通信系统正在从传统的窄带向宽带系统转变。在现有技术中,基于DVB-RCS...     

今天的网络孕育太比特的未来

太比特网络时代已为期不远,电信运营商的网络设施准备总超前于需求,他们已开始考虑当前网络建设和演进如何向未来太比特网络的平滑过渡。中国电信、Ｑｕｅｓｔ、Ｌｅｕｅｌ３Ｃｏｍｍｕｎｉｃａｔｉｏｎｓ等公司利用北电网络的方案和产品建设和优化了自己的网络。而光网络产品功能的不断演进和技术的突破正在为向未来端到端全光网演进清除障碍。     

A 200 MHz 4.8 mW 3 V Fully Differential CMOS Sample-and-Hold Circuit with Low Hold Pedestal

Wide frequency bandwidth has been internationally allocated for unlicensed operation around the oxygen absorption frequency at 60 GHz. A power amplifier and a low noise amplifier are presented as building blocks for a T/R-unit at this frequency. The fabrication technology was a commercially available 0.15 m gallium arsenide (GaAs) process featuring pseudomorphic high electron mobility transistors (PHEMT). Using on-wafer tests, we measured a gain of 13.4 dB and a +17 dBm output compression point for the power amplifier at 60 GHz centre frequency when the MMIC was biased to 3 volts V_dd. At the same frequency, the low noise amplifier exhibited 24 dB of gain with a 3.5 dB noise figure. The AM/AM and AM/PM characteristics of the power amplifier chip were obtained from the large-signal S-parameter measurement data. Furthermore, the power amplifier was assembled in a split block package, which had a WR-15 waveguide interface in input and output. The measured results show a 12.5 dB small-signal gain and better than 8 dB return losses in input and output for the packaged power amplifier.Mikko Kärkkäinen received the M.Sc. degree in electrical engineering from the Helsinki University of Technology, Espoo, Finland, in 2000, and is currently working toward the Ph.D. degree at the Electronic Circuit Design Laboratory, Helsinki University of Technology. He is interested in millimetre wave circuit design.Mikko Varonen received the M.Sc. degree in electrical engineering from the Helsinki University of Technology, Espoo, Finland, in 2002. He is currently working toward the Ph.D. degree in electrical engineering at the Electronic Circuit Design Laboratory, Helsinki University of Technology. His research interests involve millimetre-wave integrated circuits.Pekka Kangaslahti received the M.Sc. and Ph.D. degrees in electrical engineering from the Helsinki University of Technology, Finland, in 1992 and 1999, respectively. Since 1999 he has been a visiting scientist at the NASA Jet Propulsion Laboratory, Pasadena, USA. His research interests include nonlinear microwave and millimetre wave monolithic circuits, especially for signal generation in telecommunication and radar applications.Kari A. I. Halonen was born in Helsinki, Finland, on May 23, 1958. He received the M.Sc. degree in electrical engineering from Helsinki University of Technology, Finland, in 1982, and the Ph.D. degree in electrical engineering from the Katholieke Universiteit Leuven, in Heverlee, Belgium, in 1987.From 1982 to 1984 he was employed as assistant at Helsinki University of Technology and as research assistant at the Technical Research Center of Finland. From 1984 to 1987 he was a research assistant at the E.S.A.T. Laboratory of the Katholieke Universiteit Leuven, enjoying also a temporary grant of the Academy of Finland. Since 1988 he has been with the Electronic Circuit Design Laboratory, Helsinki University of Technology, as senior assistant (1988–1990), and the director of the Integrated Circuit Design Unit of the Microelectronics Center (1990–1993). He was on leave of absence the academic year 1992–93, acting as R&D manager in Fincitec Inc., Finland. From 1993 to 1996 he has been an associate professor, and since 1997 a full professor at the Faculty of Electrical Engineering and Telecommunications, Helsinki University of Technology. He became the Head of Electronic Circuit Design Laboratory year 1998. From 1997 to 1999 he was an associate editor of IEEE Transactions on Circuits and Systems I. He has been a guest editor for IEEE Journal of Solid-State Circuits and the Technical Program Committee Chairman for European Solid-State Circuits Conference year 2000. He has been awarded the Beatrice Winner Award in ISSCC02 Conference year 2002.     

全业务运营模式下的应急通信技术发展战略

应急通信是指为抢险救灾、应幸寸英发事件等提供的通信手段。随着社会的发展,自然灾害、突发事件等对社会安全造成了越来越严重的威胁,因此全业务模式下的通信运营商在应急通信技术发展方面面临着全新的考验。论文在分析目前应急通信技术现状的基础上,从应急通信技术的全方位、多手段、多应用等角度出发,阐述了适合全业务运营模式下的应急通信技术发展战略,最后对应急通信体制发展做了论述。     

卫星通信新技术现状与展望

卫星通信技术已成为陆海空天一体化信息网络系统的重要组成部分。介绍了卫星通信新技术中星上载荷、物理层传输、卫星通信天线和更高频段卫星通信等技术的现状,深入分析了它们的发展趋势,提出了有待进一步研究的关键技术,为我国卫星通信系统设计提供借鉴和思路。     

宽带卫星通信技术的现状与发展

本文综述了宽带卫星通信技术的现状,介绍了解决的关键技术问题,包括卫星数据传输技术和关键器件,以及星上处理、交换技术等。在文章的中间部分,详细阐述困拓宽带卫星系统发展的一些新的技术问题。最后,本文展望了未来宽带卫星技术的发展趋势。     

基于ATM的宽带多媒体通信卫星系统运维管理技术研究

随着卫星网络以及通信系统的逐渐研发,宽带多媒体通信卫星系统在通信领域中备受关注.宽带多媒体通信卫星系统能够实现全球无缝隙覆盖的网络互连,在通信系统研发中发挥着重要的作用.基于宽带多媒体通信卫星系统运行维护管理是保障通信卫星系统稳定运行的基础.在本文中对基于ATM的宽带多媒体通信卫星系统运维管理技术进行研究.     

基于宽带多媒体卫星网络的MAC协议

提出了一种基于MF-TDMA的宽带卫星MAC协议联合随机预约接入协议(CRRAP)。协议采用随机预约和捎带预约结合,按需分配和自由分配结合来实现的。仿真结果表明,相对于现有的方法,CRRAP减少了高信道负荷下的时延,提高了吞吐性能,并具有较高的信道利用率。     

卫星通信在因特网中的应用

因特网正在以迅猛的速度飞速发展,卫星作为一种重要的通信手段,其传输的因特网业务也日益增加。本针对卫星信道的长延时特点对TCP办议在卫星信道上的传输效率进行了分析,同时对当前的各种解决方案作了简单介绍,最后介绍了下一代卫星宽带多媒体网络。     

多媒体通信数字处理技术与质量评估因素

本文对多媒体通信的数字处理技术和质量评估因素发表了轮廓性的观感和前瞻。     

宽带卫星通信系统中强干扰抵消方法

在强干扰环境下,星上信道化器的关键部件模数转换器(ADC)会发生数据溢出,严重影响星上载荷转发性能。为此,提出了一种基于抵消思路的宽带卫星通信系统中强干扰抑制方法。该方法首先在数字域对强干扰进行检测、提取和相位幅度调整,然后在模拟域进行强干扰抵消,最后通过检测反馈保证抵消效果。给出了数字域提取滤波器的基本设计方法和实现步骤,并且结合工程实际,采用数学形态学滤波方法消除卫星宽频带噪底起伏带来的影响。研究与仿真结果表明,该方法能对强干扰进行有效抑制。     

卫星5G通信抗干扰时频同步算法

为了提高卫星通信系统的抗干扰和抗频偏能力,提出了一种在5G物理层波形中融入扩频技术的传输波形设计方案和辅同步信号(Secondary Synchroniztion Singnal,SSS)辅助主同步信号(Primary Synchronization Signal,PSS)多步联合抗干扰时频同步算法.该算法的实现分为3步:首先采用SSS辅助PSS二维时间同步得到粗同步点;然后根据粗同步点进行整数倍和小数倍频偏估计与补偿,其中小数倍频偏估计分为PSS扫频粗频偏估计和SSS辅助PSS互相关精频偏估计;最后对频偏补偿后的接收序列再次进行精时间同步和频偏补偿.仿真结果表明,所提设计方案和同步算法可以抗干信比为12 dB的干扰,并且在低信噪比下的性能优于传统算法.