基于CORBA中间件的分布式发射村远程监控系统

分布式发射机远程监控系统提升了广播系统的管理水平。本文首先介绍了分布式发射机远程监控系统的主要功能，然后给出了以无线GPRS作为物理通信层、以CORBA作为软件框架的系统总体结构，最后详细叙述了系统主要部件的功能与实现。     

分布式光伏电站远程智能监控系统设计

由于分布式光伏电站的发电系统分布复杂,传统分布式光伏电站远程智能监控系统无法对其进行有效控制,准确性和效率均不高。因此,构建准确且高效的分布式光伏电站远程智能监控系统。该系统由监控模块、感应模块和计算机群组组成。监控模块对分布式光伏电站数据传输信息、电路和元件的工作时间以及电源流量等方面的运行状况进行实时监控,并对监控对象的安全隐患进行处理。感应模块由温度传感器和光学传感器组成,温度传感器对系统电路元件的温度进行报警和调节,光学传感器实时监控分布式光伏电站中太阳能强度,这些监控数据指导使用者管理分布式光伏电站。软件给出了计算机群组对分布式光伏电站远程监控流程图,以及CISC单片机传输载波的算法代码设计。实验结果表明所设计系统具有较高的准确性和高效性。     

基于CORBA中间件的分布式发射机远程监控系统

分布式发射机远程监控系统提升了广播系统的管理水平.本文首先介绍了分布式发射机远程监控系统的主要功能,然后给出了以无线GPRS作为物理通信层、以CORBA作为软件框架的系统总体结构,最后详细叙述了系统主要部件的功能与实现.     

基于IP的分布式远程视频监控系统

视频监控系统是高速公路管理信息系统的重要组成部分。对视频监控系统的现状及其发展趋势、音视频编解码技术和网络通信技术进行了研究，在此基础上开发了一种基于IP的分布式远程视频监控系统。实际使用表明，该系统具有设备简单、投资小、视频资料数字化网络化管理、系统组网灵活可扩充性好等特点，完全能满足高速公路分布式远程视频监控的需求。该系统同样适合需要分布式视频监控的场合，如：金融、电力、地铁等，具有广泛的应用前景。     

基于单向CATV网不间断电源的远程监控系统

介绍两种典型的有线电视网不间断电源（ＵＰＳ）的远程监控系统的实现方案,设计实现了一种基于单向ＣＡＴＶ网络ＵＰＳ的远程监控通信系统,这种监控系统利用公用电话网（ＰＳＴＮ）传输ＵＰＳ信息,这样通过监控中心计算机可实现对整个ＣＡＴＶ网络中ＵＰＳ的网络化管理,从而提高网络供电质量,确保ＣＡＴＶ信号传输的可靠性。     

基于Android高清图像的视音频 监控终端的实现

基于分布式的远程监控系统,结合目前的视频监控技术的发展现状以及满足新一代的视频监控技术的特点。本文提出了一种在android移动平台上实现高清图像的远程监控终端的方法,同时实现了音视频同步的功能。     

面向多重行业应用的UT斯达康奔流监控系统

介绍了UT斯达康奔流（RollingStream）视频监控方案,该方案基于IP宽带网,是可实现图像远程监控、海量存储、远程传输、分级管理和诸多增值业务的分布式视频监控解决方案;介绍了UT斯达康奔流视频监控方案在各行业应用的实例。     

远程监控系统中基于J2ME手机软件的设计与实现

简要介绍了手机软件J2ME开发平台和开发工具，分析了手机远程监控的系统结构和功能实现，着重介绍了远程监控系统中基于JZME手机客户端软件的编写，包括用户界面设计、网络连接、云台控制、图片显示几个部分的设计与实现，并给出了部分程序流程图及运行演示。     

分布式网络行为监控系统设计与实现

本文主要探讨了分布式网络行为监控系统的设计问题,针对分布式网络行为监控系统设计的要点进行了探讨。同时,本文还论述了分布式网络行为监控系统应该如何来实现,以期能够为分布式网络行为监控系统的应用提供参考。     

基于光通信技术的远程分布式安监系统

提出了一种基于光通信技术的远程分布式安防监控系统方案.充分利用光通信系中远距离和大带宽的优点,把传统视频监控系统中视频服务器的RS485接口信息、报警输入输出接口信息和音视频数据采集等信息集成在一起通过光端机远传和接收,从而实现远程分布式部署.     

An Overlaid Hybrid‐Division Duplex OFDMA System with Multihop Transmission

In this letter, we propose an overlaid hybrid division duplex (HDD) concept for cellular systems which divides a cell into inner and outer regions and utilizes the merits of both time division duplex (TDD) and frequency division duplex (FDD). The proposed system can take advantage of both TDD and FDD without handover between two duplex schemes. Moreover, it is shown that the proposed HDD system outperforms the conventional TDD or FDD system with mobile relay stations when the synchronization issue is considered in orthogonal frequency division multiple access systems. Thus, the proposed overlaid HDD can be considered as a new framework for future cellular systems.     

Observer-Based Optimal Fault Detection and Diagnosis Using Conditional Probability Distributions

A new optimal fault detection and diagnosis (FDD) scheme is studied in this paper for the continuous-time stochastic dynamic systems with time delays, where the available information for the FDD is the input and the measured output probability density functions (pdf's) of the system. The square-root B-spline functional approximation technique is used to formulate the output pdf's with the dynamic weightings. As a result, the concerned FDD problem can be transformed into a robust FDD problem subjected to a continuous time uncertain nonlinear system with time delays. Feasible criteria to detect and diagnose the system fault are provided by using linear matrix inequality (LMI) techniques. In order to improve FDD performances, two optimization measures, namely guaranteed cost performance and$H_infty$performance, are applied to optimize the observer design. Simulations are given to demonstrate the efficiency of the proposed approach.     

Improving secret key generation for wireless communications in FDD mode

Most recent research on channel‐based key generation oriented to time division duplex system because the channel reciprocity feature is applied directly for secret key generation. Most of commercial cellular systems depend on frequency division duplex (FDD) systems. In this paper, we investigate the impact of uplink and downlink of FDD systems for the generation of shared secret keys between two parties in the presents of passive eavesdropper. In addition, we are considering improving the rate of the secret key for wireless communication in FDD mode. The main idea is to use the fading coefficient of the channels between the relay and other parties as an additional random common source for the secret key generation. Also, explore the using of channel estimation techniques to reduce the channel training sequence and study its effect on the generation of shared key for wireless communications in FDD mode. We derive the upper bound of the generated shared key rate for four scenarios and give numerical examples to reveal the performance of our suggested improvement approaches.     

Fault Detection and Diagnosis for General Stochastic Systems Using B-Spline Expansions and Nonlinear Filters

This paper presents a new fault detection and diagnosis (FDD) algorithm for general stochastic systems. Different from the classical FDD design, the distribution of system output is supposed to be measured rather than the output signal itself. The task of such an FDD algorithm design is to use the measured output probability density functions (PDFs) and the input of the system to construct a stable filter-based residual generator such that the fault can be detected and diagnosed. For this purpose, square root B-spline expansions are applied to model the output PDFs and the concerned problem is transformed into a nonlinear FDD algorithm design subjected to a nonlinear weight dynamical system. A linear matrix inequality based solution is presented such that the estimation error system is stable and the fault can be detected through a threshold. Moreover, an adaptive fault diagnosis method is also provided to estimate the size of the fault. Simulations are provided to show the efficiency of the proposed approach.     

The evolution path of 4G networks: FDD or TDD?

Frequency-division duplexing and time-division duplexing are two common duplexing methods used in various wireless systems. However, there are advantages and technical issues associated with them. In this article we discuss in detail the features, and the design and implementation challenges of FDD and TDD systems for 4G wireless systems. In particular, we present a number of advantages and flexibilities an TDD system can bring to 4G systems that an FDD system cannot offer, and identify the major challenges, including cross-slot interference, in applying TDD in practice. Due to the fact that cross-slot interference is one of the critical challenges to employing TDD in cellular networks, we also provide a quantitative analysis on its impact on co-channel and adjacent channel interfering cells     

LTE后续演进中基于频谱聚合的协同通信

大带宽无线传输有两个实现途径,一是设计频带更宽的单一系统,一是进行不同系统间的协同设计。前者是在同一种空口内采用基于多载波的频谱聚合,后者是在不同空口之间采用基于多载波并行传输的频谱聚合。通过多载波并行传输实现系统内和系统间频谱聚合,可以充分利用现有射频技术和器件,降低设备的研制和运营成本。而系统间的频谱聚合,特别是异构系统间的频谱聚合,除了可以扩展传输带宽的基本功能之外,还可以解决频分复用系统对非对称业务的支持以及时分双工保护带的利用问题,对运营商更具有商业上的现实意义。     

FEXT cancellation for twisted-pair transmission

This paper discusses a far-end crosstalk (FEXT) canceller for twisted-pair transmission. Many twisted-pair systems such as fiber-to-the-curb, very high-speed digital subscriber line, and high-speed LAN systems, use frequency-division duplexing (FDD) for duplex transmission. It is shown that the maximum reach of FDD twisted-pair system is limited by the performance of its upstream channel, which is assumed to be located at higher frequencies than the downstream channel. In order to improve the performance of such an FDD transceiver, FEXT cancellation is introduced for the channel at higher frequencies. A system arrangement and its blind startup procedure are studied when the FEXT canceller and equalizer are jointly adapted to combat channel intersymbol interference, FEXT, and other additive noise. We investigate the initial convergence and the steady-state behavior of the proposed twisted-pair system without requiring transmission of an ideal training sequence. Measured characteristics as well as analytical model of the FEXT channel are used to estimate the time span needed for the FEXT canceller. It is also shown that the memory span for the FEXT canceller is almost independent of the channel, thus making our results useful for the twisted-pair system over all different channels     

LTE FDD容量规划研究

重点分析了影响LTEFDD容量的相关因素：在此基础上,分析了LTEFDD系统的EpOCh、上下行链路信令开销占比、同时可调度用户数及VoIP用户数,给出了各项指标的具体计算模型及方法,针对15MHz的系统带宽,给出了LTEFDD的计算案例,以帮助LTEFDD无线网络系统容量规划设计。     

An adaptive notch-filter-based frequency-difference detector andits applications

A frequency-difference detector (FDD) based on an adaptive notch filter is proposed. Frequency detectors are useful in decreasing acquisition times in phase-locked-loop and Costas-loop-based clock and carrier-recovery systems. To avoid certain drawbacks associated with signal down-conversion to baseband, the input is initially processed in the bandpass domain. In applications where limits on acquisition time demand a wide closed-loop tracking bandwidth, the output of the proposed FDD has less inherent ripple and bias when compared with a quadricorrelator, a commonly used FDD. Two applications of the proposed FDD in the demodulation of BPSK data are presented     

Capacity of Generalized UTRA FDD Closed-Loop Transmit Diversity Modes

Transmit diversity techniques have received a lot of attention recently, and open-loop and closed-loop downlink transmit diversity modes for two transmit antennae have been included into universal terrestrial radio access (UTRA) frequency division duplex (FDD) specification. Closed-loop modes provide larger system capacity than open-loop modes, but they need additional side information of the downlink channel in the transmitter. In FDD systems this requires a separate feedback channel. Quantization of channel state information (CSI) in closed-loop transmit diversity schemes decreases the performance when compared to a closed-loop system where the transmitter has access to complete CSI. In this paper, we analyze the effect of quantization of CSI and deduce approximate capacity formulae for closed-loop transmit diversity schemes that are generalizations of the closed-loop schemes included in UTRA FDD specification. Moreover, we calculate approximation error and show by simulations that our approximation is tight for flat Rayleigh fading environments with and without fast transmit power control.