共查询到20条相似文献,搜索用时 15 毫秒
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A regional communication satellite system is being planned for Europe to satisfy the future needs of the European Conference of Post and Telecommunication Administration (CEPT) and the European Broadcasting Union (EBU). A model of the mission for the satellite system, based on the estimated future traffic requirements of the potential customers, has been defined to serve as a basis for system design. Starting with the postulated traffic model and with a review of the various system constraints, the present paper defines the parameters and the tradeoffs leading to the choice of the communication techniques fulfilling the requirements of the mission model. The resulting baseline communication system and its major characteristics are described. Alternate system design options are presented and commented upon. Some of these options would enhance the performance of the system but would generally involve more advanced techniques and would represent a larger technological risk. Finally, research and development topics in the field of communication technology are identified. Some of these topics are being investigated and some of the results are described in other papers. 相似文献
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WIMAX系统中的多天线技术及应用 总被引:2,自引:0,他引:2
WiMAX(全球互通微波接入)技术近年来发展迅速,逐渐成为宽带无线接入技术的热点之一。WiMAX系统能够实现高于2bps/Hz的频带利用率。为了增加覆盖范围和系统的可靠性,IEEE802.16标准支持Alamouti方案的空时码(STC)、自适应天线(AAS)和多输入多输出(MIMO)技术在内的多天线技术。多天线技术的应用能显著地提高系统容量和频谱利用率,从而大大增强WiMAX技术的竞争力。 相似文献
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根据蜂窝移动通信信道的统计模型,分析了同频干扰的统计特性,得到了以同信道小区复用因子、智能天线波束数目、旁瓣电平、同频干扰均值、方差以及射频保护比为参数的中断概率的表达式.计算表明,在现有蜂窝移动通信系统中采用智能天线,可以显著改善系统的载波干扰比,增加系统容量. 相似文献
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Wireless Personal Communications - Wireless communication is one of the fastest growing fields of communication industry. Cellular phones have shown the drastic exponential growth from the last... 相似文献
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E. Del Re S. Morosi D. Marabissi L. Mucchi L. Pierucci L. S. Ronga 《Wireless Personal Communications》2007,42(3):405-430
This paper deals with the processing techniques which are known as reconfigurable antennas: these methods are foreseen to
be a booster for the future high rate wireless communications, both for the benefits in terms of performance and for the capacity
gains. In particular, adaptive digital signal processing can provide improved performance for the desired signal in terms
of error probability or signal-to-noise ratio while the bandwidth efficiency can be increased linearly with the number of
transmitting and receiving antennas. In this article, the main antenna processing techniques are reviewed and described, aiming
at highlighting performance/complexity trade-offs and how they could be implemented in the future systems. The coexistence
of all these different technologies in a wireless environment requires high efficiency and flexibility of the transceiver.
Future transceiver implementations which are based on the Software Defined Radio technology are also reviewed and described. 相似文献
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多天线系统可以改进无线通信的容量,提高可靠性。然而,使用多天线。就意味着多个射频链路会增加天线的体积、功率、硬件,从而增加成本。天线选择是一种低成本、低复杂度的有效方法。可以利用多天线系统的多数优点。通过对MIMO系统中的天线选择技术进行概述,指出了这个领域内的一些还未解决的问题。 相似文献
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Adaptive Channel Estimation for Multiple Antenna OFDM Systems 总被引:1,自引:1,他引:0
We propose a simple adaptive algorithm for channel estimation of multiple antenna OFDM systems to provide competitive performance
with low computational complexity and tracking ability. The derivation of the mean-squared error (MSE) for the proposed scheme
is presented and the optimum selection of the parameter in the scheme is analyzed by utilizing the derived MSE expression. 相似文献
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移动通信在中国的发展势头未减,2G网络的优化以及3G网络的规划都对技术创新提出了更高的要求。分布式天线解决方案是当前和未来移动通信网络中无线资源管理的有效方式之一。介绍了分布式天线系统的种类和发展,探讨了分布式天线系统为移动通信运营商带来的好处。 相似文献
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未来的移动通信支持高速率、大容量的数据业务、多输入多输出智能天线技术是实现该目的关键技术.该文阐述了MIMO智能天线技术的的基本工作原理,分析了MIMO系统的容量,探讨了MIMO所采用的空间分集和空时编码两种重要技术. 相似文献
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移动通信系统中的智能天线技术 总被引:4,自引:0,他引:4
论述了现有系统面临着提高系统容量和改善通信质量的双重压力,而智能天线技术引入空分多址的概念,能够有效地提高系统容量。分析了智能天线技术的原理;给出了两种时分多址系统中的智能天线系统结构和比较;介绍了智能天线技术中的自适应波束合成算法。 相似文献
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随着空间事业的发展,卫星间通信在各种空间活动中成为为越来越重要的技术,本文主要介绍利用微波,毫米波和光波进行卫星间捕捉、跟踪及通信技术研究的情况,同时概要说明世界发达国家研究卫星间通信的动向。 相似文献
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数字多波束天线测试研究 总被引:1,自引:0,他引:1
探讨数字多波束天线的测试方法,对于数字多波束天线远场、近场测试的基本原理及优缺点进行了研究。详细分析了近场环境下数字多波束天线测试误差,研究了误差消除的方法。通过对误差的修正,得到较好的测试效果,从而得出数字多波束天线在近场测试结果完全可以代替远场测试的结论。 相似文献