基于XPE的嵌入式雷达显控终端系统

采用ETX-PM嵌入式硬件平台,结合Windows XP Embedded操作系统,构建了雷达显控终端系统.该系统根据具体雷达操控应用定制,降低了系统对硬件的依赖性,增加了系统的灵活性;采用EWF保护机制,提高了系统的可靠性和安全性.     

一体化数据处理与通信控制系统的设计

介绍了利用嵌入式计算机ETX模块、高速DSP TMS320F2812、新一代现场可编程器件Cyc lone、多规程通信控制器Z85C30等构成的集嵌入式计算机、串行与并行接口智能控制、现场总线为一体的数据处理与通信控制计算机系统的实现方法。硬件设计部分描述了整个设计。软件设计包含2部分:基于DSP的固件设计和基于PC机的驱动控制软件设计。重点介绍了基于DSP的固件设计方法,阐述了程序设计思想,并给出了程序流程图。     

基于ETX模块接口扩展基板电路的实现

ETX（Embedded Tecnology Extended）模块具有完整的PC功能和高效的CPU性能。通过扩展ETX模块的各种外设功能,实现的标准扩展接口有IDE、CF卡、VGA、USB、串口等扩展电路,使ETX广泛应用于各种控制领域。     

无线Mesh网络的新型建模方法研究

对无线Mesh网络准确建模是开展Mesh网络各项研究的基础,基于传统802.11协议模型来分析Mesh网络性能会导致较大的偏差。提出了一种适用于无线Mesh网络的新型模型用以计算网络饱和状态下性能参数的理论值,如丢包率、节点发送概率等,性能分析和仿真结果表明,该方法更能精确地评估无线Mesh网性能。同时在此基础上给出了路由判据ETX理论值的计算方法,该方法可用来预测ETX值而无需实测,从而有效的减少了测量误差和带宽消耗。     

基于CPCI总线CPU主控模块的设计与实现

在一些恶劣环境和军事应用环境条件下,所应用的计算机比普通商用计算机具有更高、更严的要求,提出基于CPCI总线的CPU主控模块设计方案。该方案严格遵守CPCI规范,利用高性能、低功耗、集成度高的ETXPM模块实现通用计算机的主板功能,采用TI公司的PCI2050B桥电路作为CPCI的接口模块,实现了多级总线扩展结构。该设计方案简化了设计,节省了30％的研制费用,缩短了1／2的研制周期。该模块已经通过舰载的应用测试,在-40．85℃的环境下,系统工作稳定,各接口应用正常,达到了该项目的技术指标要求。     

a high-throughput path metric for multi-hop wireless routing

This paper presents the expected transmission count metric (ETX), which finds high-throughput paths on multi-hop wireless networks. ETX minimizes the expected total number of packet transmissions (including retransmissions) required to successfully deliver a packet to the ultimate destination. The ETX metric incorporates the effects of link loss ratios, asymmetry in the loss ratios between the two directions of each link, and interference among the successive links of a path. In contrast, the minimum hop-count metric chooses arbitrarily among the different paths of the same minimum length, regardless of the often large differences in throughput among those paths, and ignoring the possibility that a longer path might offer higher throughput.This paper describes the design and implementation of ETX as a metric for the DSDV and DSR routing protocols, as well as modifications to DSDV and DSR which allow them to use ETX. Measurements taken from a 29-node 802.11b test-bed demonstrate the poor performance of minimum hop-count, illustrate the causes of that poor performance, and confirm that ETX improves performance. For long paths the throughput improvement is often a factor of two or more, suggesting that ETX will become more useful as networks grow larger and paths become longer.This research was supported by grants from NTT Corporation under the NTT-MIT collaboration, and by MIT’s Project Oxygen.Douglas De Couto received his Ph.D. in Computer Science from MIT in June 2004 for work in multi-hop wireless routing. He was a member of MIT’s Computer Science and Artificial Laboratory. He also received his S.B. and M.Eng. degrees in Computer Science and Electrical Engineering from MIT, in 1998. His research interests include multi-hop wireless networks, sensor and embedded networks, and applications of GPS. E-mail: decouto@csail.mit.eduDaniel Aguayo is a graduate student in MIT’s EECS department and a member of MIT’s Computer Science and Artificial Intelligence Laboratory. He received an S.B. in Computer Science and Electrical Engineering from MIT in 2001, and an M.Eng. in 2002. His research interests are focused on multi-hop wireless networks. E-mail: aguayo@csail.mit.eduJohn Bicket is a graduate student in MIT’s EECS department and a member of MIT’s Computer Science and Artificial Intelligence Laboratory. He received a B.S. from Cornell University. His research interests include multi-hop rooftop 802.11 networks and device drivers. E-mail: jbicket@csail.mit.eduRobert Morris is an associate professor in MIT’s EECS department and a member of MIT’s Computer Science and Artificial Intelligence Laboratory. He received a Ph.D. from Harvard University for work on modeling and controlling data networks with large numbers of competing connections. He co-founded Viaweb, an e-commerce hosting service. His current interests include routing in multi-hop rooftop 802.11 networks, modular software-based routers, distributed hash tables, and peer-to-peer file storage. He has received a Sloan Fellowship, an NSF Career award, and the ITT Career Development Chair at MIT. E-mail: rtm@csail.mit.edu