智能天线技术原理和在GSM网络的应用进展

文章论述了智能天线技术在未来移动通信系统中的重要作用,阐明了智能天线技术的原理和不同实现方式,进而介绍了智能天线的算法;最后,介绍了智能天线技术的应用优点,并探讨了实现智能天线技术的难点.     

智能天线技术原理和GSM网络的应用进展

文章论述了智能天线技术在未来移动通信系统中的重要作用,阐明了智能天线技术的原理和不同实现方式,进而介绍了智能天线的算法;最后,介绍了智能天线技术的应用优点,并探讨了实现智能天线技术的难点。     

智能天线技术对TD-SCDMA系统容量的改善

近年来,智能天线技术已成为移动通信中最具吸引力的技术之一,使用智能天线可以大大降低移动系统内的干扰,提高系统的性能和容量.基于TD-SCDMA系统,对系统的干扰及载干噪比进行了分析,重点对不同路径损耗以及误码率下,基站采用智能天线技术对系统容量的改善进行了计算和仿真.仿真结果表明,在相同的路径损耗和误码率下,采用智能天线技术可以显著地提高TD-SCDMA系统的容量.     

无线系统中的智能天线

本文介绍了智能天线在未来移动通信系统中的重要作用.分别介绍了多波束天线和自适应天线阵,阐明了智能天线的定义、组成.着重介绍了在自适应天线阵通信系统中的时空信号模型、空间信道模型和时空通信理论,比较了智能天线中的智能算法.最后,结合智能天线技术的应用进展,探讨了实现智能天线的难点和发展前景.     

软件智能天线

本文首先介绍了软件无线电和智能天线的基本概念,接着讨论了软件无线电和智能天线的融合问题--采用软件无线电的智能天线.最后给出了一个智能天线软件无线电台的方案设想.     

智能天线技术

在分析了智能天线的特点的基础上,对智能天线中所涉及的理论方法进行了深入探讨。根据天线波束处理和形成方式的不同,详细介绍了智能天线的体系结构和分类;具体阐述了实现智能天线技术中所采用的算法,并根据算法的运算性能、测量要求等不同点,给出了相应的优选策略,最后对智能天线的应用现状和发展前景进行了总结和展望。     

TD-SCDMA系统天馈部分设计的探讨

介绍智能天线的概念和馈线的几种连接方式,对3种不同的天馈连接方式进行详细对比,介绍不同种类的智能天线的特点、作用及其适应的场景,并对天馈系统设计方案的选择提出了建议.     

智能天线的测试

目前智能天线已经广泛地应用于实际的通信系统当中,具有我国自主知识产权的TD-SCDMA系统也采用了智能天线.本文对智能天线不同于普通天线的测试项目进行了介绍,并提出了相应的测试方法.     

移动通信中的智能天线技术

介绍了智能天线的概念和基本结构,分析比较了几种不同类型智能天线的基本原理,最后从三方面讨论了将智能天线引入移动通信系统以改善、提高系统性能的问题。     

智能天线技术及其应用

在移动通信领域,形成了一个新的研究热点一智能天线(Smart Antennas),本文论述了智能天线的两个主要类型和基本特性,分析了智能天线的算法,介绍了智能天线研究动向和未来移动通信系统智能天线应用前景.     

Path Clustering for Test Pattern Reduction of Variation-Aware Adaptive Path Delay Testing

In this study, a novel path clustering technique for adaptive path delay testing, where the test paths are altered according to the extracted device parameters, is proposed. The proposed algorithm is based on the k-means++ algorithm. By considering the probability function of the die-to-die systematic process variation, the proposed algorithm clusters path sets to minimize the total number of test paths. A figure of merit for clustering, which represents the expected number of test paths, is also proposed for quantitatively evaluating path clustering under different conditions. The proposed clustering method is evaluated numerically by applying it to the OpenCores benchmark circuit. Using our clustering technique, the average number of test paths in the adaptive test is reduced to less than 92 % compared with those in the conventional test. In addition, adaptive testing using the proposed technique can reduce the test patterns by 94.26 % while retaining the test quality.     

路径测试中基本路径集自动生成方法的研究

本文提出了一种有效、自动的基本路径集的生成方法,它能在一定程度上提高软件测试的效率.该方法首先设计搜索算法生成基本路径集;再根据基本块之间的依赖性分析来识别不可达路径并将其删除;然后向路径集中添加未覆盖边所在的可达独立路径;最后向路径集中添加未找到可达路径的未覆盖边所在的不可达独立路径,及线性运算所需的不可达独立路径.实验结果表明,该基本路径集生成方法能有效地生成包含尽可能多的可达路径的基本路径集.     

Distribution of Path Durations in Mobile Ad Hoc Networks and Path Selection

We investigate the issue of path selection in multihop wireless networks with the goal of identifying a scheme that can select a path with the largest expected duration. To this end, we first study the distribution of path duration. We show that, under a set of mild conditions, when the hop count along a path is large, the distribution of path duration can be well approximated by an exponential distribution even when the distributions of link durations are dependent and heterogeneous. Second, we investigate the statistical relation between a path duration and the durations of the links along the path. We prove that the parameter of the exponential distribution, which determines the expected duration of the path, is related to the link durations only through their means and is given by the sum of the inverses of the expected link durations. Based on our analytical results, we propose a scheme that can be implemented with existing routing protocols and select the paths with the largest expected durations. We evaluate the performance of the proposed scheme using ns-2 simulation.     

基于最短路问题模型的巡航导弹航迹判定

最短路问题是图论中一个多阶段决策问题。首先,通过研究巡航导弹飞行特点,确定其航迹规划属于多阶段决策问题,从而提出运用最短路问题模型判定巡航导弹航迹;其次,提出判定巡航导弹航迹的最短路问题模型的顶点的确定方法,给出了加权系数的概念及权的确定方法;最后,选定某抗击巡航导弹战例,运用最短路模型对巡航导弹航迹进行判定,结果验证了该方法的有效性和可行性。     

Efficient Path Selection for Delay Testing Based on Path Clustering

In this paper, we introduce a way of modeling the differences between the calculated delays and the real delays, and propose an efficient path selection method for path delay testing based on the model. Path selection is done by judging which of two paths has the larger real delay by taking into account the ambiguity of calculated delay, caused by imprecise delay modeling as well as process disturbances. In order to make precise judgment under this ambiguity, the delays of only the unshared segments of the two paths are evaluated. This is because the shared segments are presumed to have the same real delays on both paths.The experiments used the delays of gates and interconnects, which were calculated from the layout data of ISCAS85 benchmark circuits using a real cell library. Experimental results show the method selects only about one percent of the paths selected by the most popular method.     

Resynthesis of Combinational Circuits for Path Count Reduction and for Path Delay Fault Testability

Path delay fault model is the most suitable model for detectingdistributed manufacturing defects which can cause delayfaults. However, the number of paths in a modern design can beextremely large and the path delay testability of many practicaldesigns is very low. In this paper we show how to resynthesize acombinational circuit in order to reduce the total number of paths inthe circuit. Our results show that it is possible to obtain circuitswith a significant reduction in the number of paths while notincreasing area and/or delay of the longest sensitizable path in thecircuit.Research on path delay testing shows that in many circuits a largeportion of paths does not have a test that can guarantee detection ofa delay fault. The path delay testability of a circuit would increaseif the number of such paths is reduced. We show that addition of asmall number of test points into the circuit can help reducing thenumber of such paths in the given design.     

探索OTT TV演进路线

OTT TV是当前网络视频产业关注的热点,产业链各方都投入了很大的资源。本文从OTT TV演进的历史、当前全球发展的现状、中国发展面临的困境3个方面分析、探索OTT TV在中国可能的演进路线。     

一种共光路自动对准系统

强激光发射装置和光电跟踪系统中,光学器件多,光路复杂,光学机械零件位置的相对移动会使光轴平行度偏离,为此提出一种共光路自动对准系统.基于对准原理,利用激光发射光路,建立上、下行基准光束,使之分别与系统轴系、出射激光平行,并且通过自准直CCD测角仪测出上、下行光路的角偏差值,控制信号驱动快速控制反射镜,使快速控制反射镜两轴转动到角偏差为零值,实现发射激光与一级扩束系统对准及一级扩束系统与跟瞄系统之间的精密自动对准.实验结果表明,对准后的光轴平行度为5.21",快速控制反射镜的闭环精度不大于5".