共查询到18条相似文献,搜索用时 390 毫秒
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Ka频段卫星通信分集和自适应抗雨衰技术 总被引:1,自引:0,他引:1
Ka频段卫星通信的抗雨衰技术能够有效降低Ka频段的雨衰影响,提高Ka频段信号
传输质量。重点讨论了分集技术和自适应技术,综述了现有的抗雨衰技术及其之
间的联系,总结了热点研究方向,为今后抗雨衰技术的研究奠定了基础。 相似文献
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Ka频段的抗雨衰对策 总被引:4,自引:0,他引:4
Ka频段卫星通信系统具有广阔的应用前景,该文从Ka频段雨衰的特点以及卫星通信系统上下行链路的不同特点出发,提出了自适应抗雨衰对策。详细分析了自适应杭雨衰对策的实现原理及算法,分析得出:上行链路采用自适应功率控制,下行链路采用自适应纠错编码是解决ka频段的雨衰问题的有效方法。 相似文献
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本文首先介绍了Ka频段卫星通信雨衰产生机理及ITU-R雨衰预测模型。然后重点介绍了103°E在轨Ka卫星在我国各雨域地区(典型城市)的雨衰情况。最后联系以往Ku频段工程实施经验,总结出常用的三种Ka频段卫星通信抗雨衰补偿方法:分集技术中的业务速率分集技术、功率控制技术中的上行链路开环功率控制技术和自适应编码技术中的自适应纠错编码技术。 相似文献
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毫米波卫星通信及抗雨衰技术 总被引:2,自引:0,他引:2
卫星通信经过几十年的发展巳成为现代强有力的通信手段之一,但随着现代多媒体通信和个人通信的高速发展,低频段的卫星通信巳不能满足现代通信宽带的要求,使用更高频段的毫米波是卫星通信发展的必然趋势。毫米波卫星通信具有带宽大、干扰小等特点,但由于降雨衰减较大,研究毫米波卫星通信的抗雨衰技术成为卫星通信技术研究的热点。我国应密切注意卫星通信发展的最新趋势,加大力度进行高频段卫星通信系统的研究和开发。 相似文献
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C. Riva L. Luini M. D'Amico R. Nebuloni A. Marziani F. Consalvi F.S. Marzano 《International Journal of Satellite Communications and Networking》2019,37(5):423-436
Terabit capacity and very high data rates are required for the near‐future broadband satellite communication systems, mainly for multimedia services. The increased capacity can be obtained by using the larger bandwidth available at higher frequency bands, like Ka and Q/V. However, severe detrimental atmospheric effects impair radio waves at these bands, which require the extensive use of fade mitigation techniques, such as link power control, site diversity, or on‐board adaptive power allocation. The Alphasat Aldo Paraboni propagation experiment was designed and supported by the Italian Space Agency, and implemented by the European Space Agency, to better characterize the atmospheric propagation channel at Ka band and Q band, to support the design of future satellite systems. In Italy, 3 ground stations have been installed and are acquiring the Alphasat beacon signals: the 2 ASI main ground stations in Tito Scalo (Southern Italy) and Spino d'Adda (Northern Italy) and the La Sapienza‐FUB station in Roma (Central Italy). The 3 stations cover quite distant locations in Italy, with different climatic characteristics. This paper describes the main features of the experimental setup in the above stations and presents some examples of measurements and results. 相似文献
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Khairayu Badron Ahmad Fadzil Ismail Md Rafiqul Islam Khaizuran Abdullah Jafri Din Abdul Rahman Tharek 《International Journal of Satellite Communications and Networking》2015,33(1):57-67
Radio wave propagation plays a very important part in the design and eventually dictates performance of space communication systems. Over time, the requirements of satellite communication have grown extensively where higher capacity communications systems are needed. Escalating demands of microwave and millimetre wave communications are causing frequency spectrum congestion. Hence, existing and future satellite system operators are planning to employ frequency bands well above 10 GHz. The challenge in operating at such high frequencies for communication purposes is that there exists stronger electromagnetic interaction between the radio signals and atmospheric hydrometeors. Such instances will degrade the performance of such high frequency satellite communication systems. The development of a revised model for a better‐improved rain fade prediction of signal propagations in tropical region is considered very important. Researchers and engineers can employ the model to accurately plan the future high frequencies satellite services. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Michael Schmidt Michael Schönhuber Johannes Ebert Harald Schlemmer Franz Teschl 《e & i Elektrotechnik und Informationstechnik》2014,131(6):150-154
The bandwidth demand in radio communications is increasing every year, not only in the terrestrial domain, but also in the satellite domain. The Ku Band is already at its capacity limit and the higher Ka Band is filling rapidly and will reach its capacity limit in the years to come. From both the research and commercial point of view it is important to explore the next frontier for satellite communication, which is the Q/V band. In radio communication it is not only a simple up-scaling of the frequency to achieve the same gain with smaller antennas as with bigger antennas in lower bands, but it is the challenge to handle the different wave propagation properties of these higher bands. In Q/V band the atmospheric attenuations are changing quicker than in lower bands (up to 3 dB/s) and the scintillation caused by gas density changes are in the region of 1 Hz with amplitudes of up to 2 dB. The newly developed ground station in Graz will now help to answer basic research questions in the exploration of the Q/V band. The questions are for instance: Which fade mitigation technique is the best to operate a modem via the Q/V band channel or which averaging times shall be used to have the highest availability with the lowest required margins. Joanneum Research will investigate the optimal operation of this channel together with researchers from the University of Rome Tor Vergata and in the wave propagation domain together with the Politecnico di Milano. The first part of the paper describes the ground station design for the communication experiments to be operated over the Q/V band communication transponder of Alphasat, called Aldo Paraboni payload. In addition to the Q/V band Ground Station, in the frame of ESA’s ARTES-5 programme, a beacon receiver was designed and manufactured, for measurement of the Ka/Q band beacon signals provided by the Alphasat Technological Demonstration Payload 5 as well. This receiver measures co-polar and cross-polar signal at Ka and Q band with one antenna feed and provides a perfect measure of the actual signal quality. 相似文献
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Felix Cuervo Antonio Martellucci Juan Rivera Castro Michael Schmidt Michael Schnhuber 《International Journal of Satellite Communications and Networking》2019,37(5):437-448
The use of higher frequencies for satellite multimedia communication systems calls for research of the atmospheric propagation effects at these bands (rain, cloud and gaseous attenuation, scintillation, and depolarization). Alphasat was successfully launched on 25 July 2013. This largest and most powerful European telecommunication satellite carries, besides a commercial payload belonging to the mobile satellite communication provider Inmarsat, several Technology Demonstration Payloads (TDPs) from ESA. One of them is the Aldo Paraboni payload (TDP5) for Q/V‐band communication and Ka/Q‐band propagation experiments. These experiments explore future applications in satellite communication and measure how the Earth's atmosphere affects the propagation of electromagnetic waves. Under ESA contract, JOANNEUM RESEARCH designed, developed, and operates a Q/V‐band communication ground station and a Ka/Q‐band propagation terminal. The experimental site is equipped with ancillary equipment including a multifrequency radiometer profiler, a 2D video disdrometer (2DVD), and meteorological stations. This paper reports on the experimental setup, data processing, and obtained results. 相似文献
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Juan J. Rivera Antonio Martellucci Philippe Sivac Edoardo Benzi Alberto Pandolfi Domenico de Bernardo Stefano Falzini Giuseppe Codispoti 《International Journal of Satellite Communications and Networking》2019,37(5):397-409
This paper provides an overview of the space segment of the Aldo Paraboni mission on the Alphasat satellite and the technology programme that has developed one of the most powerful geostationary satellites in Europe. The Aldo Paraboni technology demonstration payload, funded by ASI under European Space Agency's Advanced Research in Telecommunications System Programme, was embarked as a hosted payload on the Alphasat satellite, launched on 25 July 2013. The Aldo Paraboni payload is composed of two main elements, an experimental communication payload operating at Q/V bands (COMEX) and a scientific payload formed by 2 beacons at Ka and Q bands (SCIEX). The Aldo Paraboni payload is a key technology element of the Aldo Paraboni Mission, which covers two main objectives: the communication segment of the mission aims at assessing the performance of satellite communication links at Q/V bands and investigating use Fade Mitigation Techniques (FMT, eg, Adaptive Coding and Modulation defined in DVB‐S2 standard), while the scientific segment aims at characterizing in time, space, and frequency the K and Q band radio channel over Europe to permit development and improvement of propagation channels for slant paths. 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1984,72(11):1637-1644
Nippon Telegraph and Telephone Public Corporation (NTT) initiated the world's first 30/20-GHz domestic satellite communication system for commercial use, using CS-2s launched from Japan in 1983. This system utilizes TDMA digital communication in the trunk transmission route of the public communication network, which includes interregional-center routes and main-island-to-remoteisland routes. Small transportable earth stations enable easy access to the public communication network from any place in Japan. The adoption of the 30/20-GHz band enables use of a compact on-board antenna that has a shaped beam that effectively covers the main islands of Japan. It also enables the use of high-performance, compact antennas at the earth stations. These antennas can easily be installed on the roof of telephone offices or set on motor vehicles. One apparent disadvantage of using the 30/20-GHz band is rain attenuation. However, NTT has realized a commercial system that is affected very little by rain attenuation. This was accomplished by utilizing high-performance radio equipment and by concentrating on appropriate system design. Adoption of the 30/20-GHz band is quite significant because the wide bandwidth available enables construction of high-capacity economical transmission systems. It also enables use of small antennas, which allow construction of high-speed digital direct-to-user transmission systems using small earth stations. These expand the application of the domestic satellite communication system to even small service areas. Therefore, NTT considers satellite communication to be of primary importance for its proposed digital communication network, and has begun research on a high-capacity, economical, multibeam communication satellite system using the 30/20-GHz band. This paper describes the 30/20-GHz band radio technology, digital communication technology utilizing high-speed TDMA, and operational technology in the public communication network. 相似文献
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Aghvami A.H. Gemikonakli O. Kato S. 《Selected Areas in Communications, IEEE Journal on》1992,10(6):1030-1036
The authors discuss the possibility of transmitting synchronous digital hierarchy (SDH) signals through two-link nonlinear satellite channels. Transmitting such high bit rate signals through a standard 54 MHz or 36 MHz transponder bandwidth requires the use of high-level modulation schemes. The techniques and technologies needed to make the use of 16-ary quadrature amplitude modulation (QAM) and 64-ary QAM transmissions feasible for future satellite communication systems are examined. It is shown that it is possible to transmit a synchronous transport module-level 1 (STM-1) signal through a standard 54 or 36 MHz transponder bandwidth using 16-ary QAM or 64-ary QAM transmission, respectively, for the 6/4 GHz band. However, for higher frequency bands, due to high fade margins needed to achieve the high availability and performance for SDH systems, is not practical to transmit the STM-1 signal through such standard transponder bandwidths 相似文献
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Ka频段卫星通信因其具有可提供的带宽大(3.5GHz)、通信容量大、波束窄、终端尺寸小,轨道平面内可容纳的卫星多和抗干扰能力强等优势成为未来卫星通信的必然趋势。Ka频段卫星通信面临的一个巨大挑战在于它受气象因素的影响大,这一度使研究人员认为Ka频段卫星通信是不可能实现的。降雨、闪烁、大气吸收等因素都会导致Ka频段地空链路信道质量的恶化。根据Ka频段卫星通信的特点,分析了降雨衰减的特性,提出了几种抗雨衰的办法。 相似文献