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71.
NIE Xin ZHANG JianHua LIU ZeMin & ZHANG Ping Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts Telecommunications Beijing China Wireless Technology Innovation Institute 《中国科学:信息科学(英文版)》2011,(9):1945-1956
Relay,which serves to enhance the performance of future communication networks,is one of the most promising techniques for IMT-Advanced systems.The potential performance improvement of relay is investigated in this work.Our investigation consists of two steps.In the first step,to obtain a better understanding of the fundamental properties of relay channels,we conducted outdoor measurements at 2.35 GHz with 50 MHz bandwidth in a typical urban area of China.Three links constituting the relay transmission,i.e.... 相似文献
72.
LUO MingXing YANG YiXian WANG LiCheng & NIU XinXin Information Security Center State Key Laboratory of Networking Switching Technology Beijing University of Posts Telecommunications Beijing China Key Laboratory of Network Information Attack Defence Technology of MOE National Engineering Laboratory for Disaster Backup Recovery Beijing University of Posts Telecommunications... 《中国科学:信息科学(英文版)》2010,(3):648-658
Our concern, in the paper, is to construct information-theoretic secure network coding in the presence of eavesdroppers. Based on the generalized attack model and all-or-nothing transformation, the security of network coding in the generalized combination network can be characterized by the network capacity and the min-cut bound of wiretapping set from the source. Furthermore, it can be extended to any directed acyclic networks with single source. Compared with the traditional results, we construct informat... 相似文献
73.
ZOU YuLong ZHENG BaoYu & ZHU Jia Institute of Signal Processing Transmission Nanjing University of Posts Telecommunications Nanjing China 《中国科学:信息科学(英文版)》2010,(2):325-334
Cooperative diversity is proposed as a means to improve the wireless transmission performance, which can effectively combat the wireless fading through sharing the antennas between source and relay nodes. In this paper, considering the practicability, we investigate the use of half-duplex relay, rather than full-duplex relay, for the opportunistic cooperation diversity. Two combining methods, namely selection diversity combining (SDC) and maximum ratio combining (MRC), are utilized for the implementation of... 相似文献
74.
要使现有的模拟电路故障诊断算法适用于大规模电网络,必须将大规模网络分解成互不耦合的小规模网络。本文讨论了将支路撕裂法用于大规模模拟电路的快速ATPG,给出了文献〔1〕中算法的五个缺陷,并对之逐一进行了解决。并在altos-68000上用FORTRAN77编制了一个可以完成200条支路,40个节点以内的任意可撕裂的线性网络的故障定位通用程序LAFDP。文中给出运用程序LAFDP进行故障定位的例子。 相似文献
75.
拉美的光通信场市场随各国经济的改革和复兴走上了快速发展之路,与发达国家积极合作和大力建设海底光缆是其发展的两大特点。本文概要介绍了拉美6个主要国家的光通信市场发展前景、现状及电信投资额,并给出了该地区正在或计划建设的海底光缆系统的具体情况。 相似文献
76.
本文根据九个不同类型微波通信局(站)的微波设备在工作位对工作人员微波辐射量级的测试取得的大量数据,进行了分析处理,得出微波站工作位最大漏能为2.5μW/cm~2。文中还分析了其测试结果,找出了微波通信设备电磁波能量泄漏途径,提出了减少微波通信设备泄漏的防护措施及建议。 相似文献
77.
Ribs and fans are interesting geometric entities that are derived from a given Bezier curve or surface based on the recent theory of rib and fan decomposition. In this paper, we present some of new geometric properties of ribs and fans for a Bezier curve including composite fans, rib-invariant deformation, and fan-continuity in subdivision. We also give some examples for the presented properties. 相似文献
78.
介绍仅用一个主开关管及一个辅助开关提高设备的输入侧三相交流功率因数的零电流关断(ZCS)升压型变换器的基本电路,说明升压电感电流工作在不连续状态的必要性。采用三相整流电压的6次谐波前馈(注入),以减小三相电源的5次庇波电流。减小主开关管关断损耗采用了零电流关断电路。 相似文献
79.
IP技术与IP业务在国际上大行其道,强烈地冲击着传统电信网,同时改变着电信市场的竞争格局。IP技术将成为下一代电信网的核心技术之一,它对中国电信运营商是一种机遇,加快向IP技术升级,将在未来国际竞争中取得主动权。然而,从美国电信市场竞争格局的变化中,我们强烈感受到外国运营商卷入的压力。因此,IP技术将成为中国电信业国际竞争力中十分重要的因素。 相似文献
80.
FU Zi-xi HU Chun-jing PENG Tao LU Qian-xi WANG Wen-bo Wireless Signal Processing Network Lab Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts Telecommunications Beijing China 《中国邮电高校学报(英文版)》2011,(5):22-29,36
A hybrid system of cellular mode and device-to-device(D2D)mode is considered in this paper,where the cellular resource is reused by the D2D transmission.With the objective of capacity maximization,the power optimization of D2D sub-system is considered,taking into account quality of service(QoS)requirement.The power optimization problem is divided into two stages:The first stage is the admission control scheme design based on the QoS requirement of D2D users,and the second is power allocation to maximize agg... 相似文献