网管支撑系统运行质量管控的研究与实现

本文提出了一种通信网网管支撑系统质量管控体系,研究通过网管支撑系统运行质量指标的量化来实现网管支撑系统质量管控的方法,并对具体实现方法的技术进行了阐述,为网管支撑系统的质量管控形成良性的优化循环,以此来提高通信实体的维护、服务、管理水平。     

无线多跳链路选频通信

加入无线中继节点构成多跳传输链路,可以实现较长距离的无线通信。本文在已有文献的基础上,重点研究救灾机器人和遥控终端间的选频建路协议,在链路各节点间按照选频通信的方式搭建传输链路;并在“全节点比例定时交替传输协议”基础上加入选频通信,设计选频传输协议,避免数据包间的相互碰撞。经仿真测试,设计的协议按照选频通信方式搭建了传输链路并实现了数据的无碰撞双向传输。     

地基多站无源定位系统通信设计及仿真

对于地基多站无源定位系统而言,为形成协同作战能力,多站间的相互通信是其中的关键设计环节。针对多站无源定位系统的通信需求进行了分析,从通信的带宽、远距离传输以及安全性等多个角度进行了应用设计,并通过仿真测试验证了该设计能够满足需求。     

面向作战仿真的多分辨率通信系统建模技术

目前信息系统建模技术已成为作战仿真系统需要突破的关键技术, 重点研究通信系统的建模技术, 建立了通用的数据处理模型框架, 实现了战场信息传输、处理、存储、表示的规范性和一致性; 提出了完整的多分辨率通信系统建模方法, 实现了对作战仿真中通信网络、链路终端、通信节点、消息类型、通信方案的建模。在海军某作战仿真系统中得到了应用, 仿真实验表明, 通信系统模型满足作战仿真系统的作战需求, 提高了作战仿真的真实性和合理性。     

城市轨道交通车地无线通信安全风险研究

基于通信的列车运行控制(CBTC)技术已被广泛地应用于我国城市轨道交通建设中,首先,分析了CBTC系统的组成及特点;接着,研究了目前CBTC系统中基于IEEE 802.11协议的车地无线通信子系统存在的信息安全风险、可能遭致的黑客攻击手段,以及现有信息安全防护措施存在的问题;最后,展望并提出了今后轨道交通信息安全研究的工作重点,以期加强对轨道交通可靠运营的安全保障。     

对通信工程项目施工的时间管理

在通信工程项目施工中,时间管理是非常重要的一环,可以说时间管理的好坏会决定整个项目的成败,因此要正确认识到通信工程项目中时间管理的重要性。本文通过对通信工程项目时间管理的重点和难点的分析,以及一个实例来对通信工程项目施工的时间管理进行详细的探讨。     

VPN技术在网络通信中的应用

随着网络技术的发展,对网络通讯的需求也越来越高,本文针对VPN基本原理和VPN的关键技术等方面进行了深入研究,并从应用成本、工程管理以及用户的扩展性进行了分析。为了使VPN技术能够在工程上得以很好地应用,文中从有线测试、无线测试进行了分析,试验结果表明该技术可以在工程上加以推广应用。     

Pilot-aided sampling frequency offset estimation and compensation using DSP technique in DD-OOFDM systems

To improve the outage performance of an optical orthogonal frequency-division multiplexing (OFDM) system under the frequency offset between the sampling clocks in the transmitter and receiver, a pilot-aided sampling frequency offset (SFO) estimation and compensation scheme for the optical OFDM system with intensity-modulation and direct-detection (DD-OOFDM) is experimentally demonstrated. The experimental and simulated results show that the scheme can work effectively even with large sampling frequency offsets. In addition, it can achieve a good bit error rate (BER) performance without the sampling clock frequency synchronization in the receiver.     

An adaptive power pricing scheme for improved fairness in energy‐constrained cooperative networks

This paper presents an adaptive power pricing scheme to address the fairness issue with relay selection and power allocation in decode‐and‐forward‐based opportunistic relaying networks, which is focused on the scenario where a distributed energy‐constrained cooperative communication system is employed over Rayleigh fading channels. Specifically, the proposed scheme is conducted analytically by obtaining the mathematical expression for the symbol error probability using the statistical characteristic of the signal‐to‐noise ratio, and it also takes the residual energy of nodes into consideration. Numerical results show that the proposed scheme has the advantage of better system reliability and further improves the throughput of the whole network compared with previous algorithms without considering fairness. Copyright © 2013 John Wiley & Sons, Ltd.     

Comparison between power line communication multipath model and coaxial cable interferometer theory

The authors have studied a new method to find parameters of broadband power line communication channel model. Lossless power line communication channel model is compared with classical interferometers approach to develop this model. The authors also used coaxial cables to simulate a multipath channel, because it can behave like a lossless power line communication channel. Thus, measurements were carried out with a network analyzer to find S parameters. The modeling parameters, for the multipath model were found after using MATLAB software and classical interferometers approach. Then, theoretical and experimental results are presented and compared. Copyright © 2012 John Wiley & Sons, Ltd.