域间流量工程的研究与实现

域间的流量工程策略有助于保证业务流的端到端QoS,提高网络资源利用率并实施跨域的快速恢复。本文介绍了域间流量工程的研究现状,并详细分析了不同的实现方法。最后指出了实施域间流量工程的困难所在及以后的研究方向。     

蓬勃发展中的中国卫星通信事业

从70年代初期开始,我国利用国际卫星组织(INTELSAT)的卫星建立了国际卫星通信。国内卫星通信是从1985年开始的。当时按照国家确定的“租星过渡,C频段起步”的正确方针,建立了国内卫星通信网。经过20多年的努力,我国已建立了一个应用广泛、技术先进、业务较为齐全、具有一定规模的卫星通信网。与此同时,我国卫星通信的科研、工业也取得了巨大发展。     

Experimental investigation of MIMO relay channels statistics and capacity based on wideband outdoor measurements at 2.35 GHz

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....     

Secure network coding in the presence of eavesdroppers

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...     

Performance evaluation of half-duplex relay-based opportunistic cooperation diversity

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...     

Quality of service aware admission control in cognitive device-to-device network

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...     

几个互联网数字的趣味解读

40岁：email已到不惑之年email多少岁了你知道吗？是的,大家不要惊讶,作为一种传统的互联网交流方式,它确实已经有40年的历史了。它从计算机科学家们手中的小众技术,发展成为人们网络沟通最常用的联系方式。     

Realizing Zinc Blende GaAs/AlGaAs Axial and Radial Heterostructure Nanowires by Tuning the Growth Temperature

Vertical zinc blende GaAs/AlGaAs heterostructure nanowires were grown at different temperatures by metalorganic chemical vapor deposition via Au-assisted vapor-liquid-solid mechanism.It was found that radial growth can be enhanced by increasing the growth temperature.The growth of radial heterostructure can be realized at temperature higher than 500℃,while the growth temperature of axial heterostructure is lower than 440℃.The room temperature photoluminescence properties of the nanowires were investigated and the relevant growth mechanism was discussed.     

大规模模拟电路的ATPG实现

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。     

拉丁美洲的光通信和市场

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。