LTE和Wi-Fi系统间灵活频谱使用关键技术

针对授权辅助接入,提出了一种适用于LTE-U与Wi-Fi共同使用免授权频段的方法,该方法无需更改Wi-Fi协议就能实现LTE-U与Wi-Fi比例公平使用免授权频谱,有效聚合授权频谱与免授权频谱,提升频谱效率,为用户提供更好的业务体验。     

Reducing PAPR of SC‐FDMA Signals through Simple Amplitude Predistortion

A novel peak‐to‐average power ratio (PAPR) reduction method is proposed for single‐carrier frequency‐division multiple access (SC‐FDMA) signals. The proposed method deliberately distorts the amplitude values of a few of the complex modulated symbols that cause peaks beyond a predetermined threshold in the samples of the output signal. The method then marks the location indices of the distorted symbols by using a pilot block at the transmitter without transmitting side information. At the receiver, the method is then able to recover the distorted amplitude values through the marked location indices. Computer simulation results show that when compared to conventional SC‐FDMA signals, the proposed scheme can effectively reduce the PAPR of SC‐FDMA signals with asymptotically consistent bit error rate (BER) performance.     

进出口老视成镜质量检测与产品标准

本文介绍了世界各主要国家对老视成镜产品市场准入方面的规定,并对各国产品标准之间的差异进行比较分析,以供相关生产、贸易企业和检测机构参考,旨在减少非关税壁垒对老视成镜产品进出口贸易带来的不良影响。     

Infotainment and road safety service support in vehicular networking: From a communication perspective

Vehicular ad hoc networking is an emerging technology for future on-the-road communications. Due to the virtue of vehicle-to-vehicle and vehicle-to-infrastructure communications, vehicular ad hoc networks (VANETs) are expected to enable a plethora of communication-based automotive applications including diverse in-vehicle infotainment applications and road safety services. Even though vehicles are organized mostly in an ad hoc manner in the network topology, directly applying the existing communication approaches designed for traditional mobile ad hoc networks to large-scale VANETs with fast-moving vehicles can be ineffective and inefficient. To achieve success in a vehicular environment, VANET-specific communication solutions are imperative. In this paper, we provide a comprehensive overview of various radio channel access protocols and resource management approaches, and discuss their suitability for infotainment and safety service support in VANETs. Further, we present recent research activities and related projects on vehicular communications. Potential challenges and open research issues are also discussed.     

WiMAX技术在高级量测体系中的应用

高级量测体系是智能电网的重要量测系统,它需要有能够从智能电表收集数据以及发送控制命令到智能电表的实时双向通信网络。WiMAX是宽带无线接入技术,被看作是代替缆线和DSL提供"最后一公里"宽带接入的标准技术。针对AMI的实际情况,结合WiMAX的主要特性,讨论了WiMAX在AMI通信网络中的具体应用,并分析了该应用具有的优势。该应用具有宽带无线接入、覆盖范围广、结构灵活、安全性高,互操作性等特点。     

SSL VPN技术在高校图书馆中的应用研究

简单介绍了VPN原理和技术.通过分析OpenVPN的技术特点,结合高校图书馆的实际需要,详细阐述如何在Linux环境中利用OpenVPN技术构建远程安全访问SSL VPN服务器,实现校外用户远程访问图书馆信息资源.     

多级质量归零管理系统中的访问控制

针对航天企业在质量归零管理信息化过程中遇到的对归零信息和归零过程的多级、多任务和多角色访问控制问题展开研究.在构建面向集团-院-厂所的三级归零管理业务模型的基础上,分析质量归零过程中对归零信息和归零流程的访问控制需求,提出基于任务和角色的扩展访问控制( Extended Task&Role Based Access Control,ETRBAC)模型,该模型将型号权限、产品权限、组织权限和任务权限进行综合,实现了对归零信息和归零流程的多维度访问控制.在理论研究的基础上,设计开发了访问控制组件,并通过软件的实施,验证该访问控制策略的有效性.     

ADO技术在大坝安全监测中的应用

通过对ADO与几种不同数据数据访问技术DAO、ODBC的描述及对比，并通过分析ADO技术在大坝安全监测中的具体应用，阐明了ADO技术在大坝监测中的应用前景及必要性。     

SQL server的分布式光纤温度传感器校准数据采集方法

利用Lab VIEW数据采集系统平台,提出了一种采用SQL server技术访问InterBase数据库的数据采集方法.该方法先将分布式光纤温度传感器自带的GDB格式数据,以数据表的形式存入SQL Server特定数据库中,然后通过Lab VIEW数据采集系统以数组形式显示,最后将数组数据保存在Excel文件中,以便数据分析处理.运行调试结果表明,该方法对被校分布式光纤温度传感器的校准数据采集保存快速,操作分析方便,可视化效果好.