下一代无线通信概念和技术

下一代无线通信(NextG:Next-generationwireless)的主流是随时随地的无线通信系统和无缝的高质量无线业务。概述了随时随地的无线通信和业务发展情况,并且介绍了为下一代无线通信的发展提供基础的关键技术。     

高可靠低功耗Ka频段星载有源相控阵冗余备份技术

与传统的星载平台大多用开关来备份高失效率的微波通道模块不同,提出以无源器件来替代开关进行冗余备份的方法,将电桥集成于原有的波束形成网络,对Ka频段星载有源相控阵中的变频模块进行冷备份.设计并研制了集成电桥的波束形成网络,在23.5～25 GHz工作频段内,该网络的测试驻波比小于1.8,均方根幅度一致性小于0.4 dB,...     

一种无接缝纹理映射算法的并行实现

随着多核处理器的问世,并行编程变得简单和必要。通过对一种纹理映射算法的研究,对其耗时部分进行并行化,以加快算法运行速度。该纹理映射算法先建立三维网格顶点和视点之间的对应关系,然后利用重心坐标权重插值的颜色填充方法构造出一个无接缝的纹理图像。通过利用算法过程中存在的并行性,对算法进行并行实现。实验结果显示,能够得到一个无接缝的纹理图像,而且在双核处理器上的平均加速比达到了1.70。     

一种利用信源冗余的Turbo均衡新算法

为克服无线衰落信道中严重的符号间干扰(ISI)的影响,提出了一种新的利用信源冗余的Turbo均衡算法。该算法将联合信源信道译码技术与Turbo均衡技术结合起来,在均衡、译码、信源之间建立起软信息交互的环路,有效提高了整体接收的性能。外信息传递(EXIT)图分析与计算机仿真均表明,尽管信源冗余给译码器带来的性能提升较为有限,但是将这部分信息反馈回均衡器后,在严重ISI信道,信源冗余度为70%时,整体接收的性能改善约为9.5 dB,基本达到了理想加性高斯白噪声（AWGN）信道下的误码性能。     

基于预算机制的非结构化P2P网络分段搜索策略

在非结构化P2P网络中,降低消息冗余,提高搜索的效率,一直是资源搜索的关键问题.目前非结构化P2P网络均采用生存时间（Time-To-Live）机制控制搜索算法的深度,但是同时产生了大量的冗余消息,严重影响了网络的利用率.为了能够在保持高搜索效率的前提下减少冗余消息的数量,提出了一种基于预算机制的非结构化P2P网络分段搜索策略DBudgetSearch.DBudgetSearch将搜索过程分为两个阶段,并在每个阶段中使用预算机制来控制消息转发的数量和导向,根据邻居节点的连接度大小来选择消息的转发对象.分析和试验结果表明,DBudgetSearch导向性好,算法搜索效率高,能够有效减少冗余消息.     

Design of testable sequential circuits by repositioning flip-flops

This paper presents a technique to enhance the testability of sequential circuits by repositioning flip-flops. A novel retiming for testability technique is proposed that reduces cycle lengths in the dependency graph, converts sequential redundancies into combinational redundancies, and yields retimed circuits that usually require fewer scan flip-flops to break all cycles (except self-loops) as compared to the original circuit. Our technique is based on a new minimum cost flow formulation that simultaneously considers the interactions among all strongly connected components (SCCs) of the circuit graph to minimize the number of flip-flops in the SCCs. A circuit graph has a vertex for every gate, primary input and primary output. If gatea has a fanout to gateb, then the circuit graph has an arc from vertexa to vertexb. Experimental results on several large sequential circuits demonstrate the effectiveness of the proposed retiming for testability technique in reducing the number of partial scan flip-flops.     

异构作动系统的效率特性与能量管理分析

为提升由液压作动器和电动静液作动器组成的异构作动系统的能量特性,首先建立数学模型,并根据给定参数分析效率特性,在此基础上,提出能量综合管理策略,最后进行仿真分析.结果表明:液压作动器和电动静液作动器的效率特性存在明显的区别,且基于效率特性设计的能量综合管理策略具有显著的优势.     

Fast Duplicate Address Detection for Seamless Inter-Domain Handoff in All-IPv6 Mobile Networks

In All-IP networks, each computer or communication equipment needs an IP address. To supply enough IP addresses, the new Internet protocol IPv6 will be used in next generation mobile communication. Although IPv6 improves the existing Internet protocol (IPv4), Duplicate Address Detection (DAD) mechanism may consume resources and suffer from long delay. DAD is used to make sure whether the IP address is unique or not. When a mobile node performs an inter-domain handoff, it will first generate a new IP and perform a DAD procedure. The DAD procedure not only wastes time but also increases the signaling load on Internet. In this paper, we propose a new DAD mechanism to speed up the DAD procedure. We create a DAD table in access or mobility routers in All-IP networks and record all IP addresses of the area. When a new IP address needs to perform DAD, it can just search in the DAD table to confirm the uniqueness of the address. Furthermore, we propose a new method, Fast Duplicate Address Detection (Fast DAD), to reduce data search time. Simulation results show that our method outperforms the existing DAD methods.     

量子纠错电路的模块化设计与优化

在无测量状态下,对三量子位纠错电路进行设计和优化,提出模块化概念设计和优化量子纠错电路。随着量子位的增加,三量子位纠错电路作为模块可用于五量子位纠错电路中,五量子位纠错电路作为模块可用于七量子位纠错电路中,以此类推。少量子位纠错电路作为多量子位纠错电路的部分模块使用,可使得多量子位纠错电路设计简化,冗余位减少,使之量子代价较低。     

TV-GPS技术融合实现无缝定位分析

介绍了现有的电视基础设施以及GPS定位技术,论述了TV-GPS系统如何利用地面广播电视辅助信号进行定位的新技术,给出了TV-GPS系统的原理与机制。该系统充分融合现有的TV和GPS技术,使用未经修改的广播电视信号,在全球定位系统最受挑战的室内和市区进行定位和定时。仿真显示接收到的可用GPS卫星颗数越多,定位误差越小,从而可以利用TV信号来弥补高楼耸立的边缘地带GPS定位的缺陷,同时也提出了TV与GPS算法融合模型框图。实现了室内和室外快速、可靠、精确的无缝融合定位技术。