基于低压电力线传输网的无线光通信研究

介绍一种低压电力线传输网与无线红外传输相结合的通信机制,分析了调制方式、信号耦合方式和阻抗匹配以及影响信号传输的因素,给出了增强带负载能力和消除电力线负载效应的解决方法。实验表明,选择合适的调制方式与载波频率可降低电力线信道噪声的影响,实现了低压电力线与大气信道视距内信号稳定可靠传输,为短距离无线光通信提供一种新方法。     

基于周期平稳高斯噪声模型的LPLC系统研究

低压电力线信道噪声干扰强、阻抗变化大、信号衰减剧烈,因此低压电力线道特性研究及建模是LPLC-OFDM系统研究的关键。文中采用周期平稳高斯噪声模型和多径信道模型,用少量参数准确描述了实际低压电力线信道特性,并在此信道模型下,建立了LPLC-OFDM系统仿真平台,完成了系统性能分析,为低压电力线载波通信相关问题的研究提供了重要基础。     

低压电力线载波通信结合滤波器设计

低压电力线作为载波通信信道时,其通信特性并不理想,各种负载、用电设备及外界都将引起大量的噪声,给电力线载波通信带来了严重的干扰问题,从而影响电力线通信系统的性能。为了保证载波通信信号和数据的有效传输,通过电路分析并设计一种低压电力线载波通信结合滤波器,经仿真与实验该滤波器能有效过滤低压电力线载波通信信道中的各种干扰信号,从而达到了保证载波通信信号和数据的有效传输的作用。     

低压电力线通信系统信道特性分析

低压电力线通信压是智能电网一种重要的形式。文章通过分析低压电力线信道的网络拓扑、阻抗特性、衰减特性和噪声特性等,研究建立低压电力线通信噪声模型,针对低压电力线衰减特性建立基于多径衰减信道模型和基于FIR信道模型。这些信道模型建立与仿真是进一步深入理解低压电力线信道特性的理论基础。     

室内电力线信道特性分析

利用低压电力线高速、可靠地传输通信数据可以节省专用通信线路,但是低压电力线路特别是室内电力线路网络结构和负载特性复杂,需要对信道有深入的了解。文章简要介绍了电力线通信的原理,并分析了电力线信道的时变性、噪声特性、阻抗特性及衰减特性,为电力线通信系统的设计提供了参考。     

基于正交频分复用技术的低压电力线通信系统模型

针对目前低压电力线通信技术的传输复杂性及外部噪声失真等问题,本文基于正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)调制技术模型,建立了低压电力线信道的通信传输模型,并在MATLAB软件中仿真研究了低压电力线通信系统的传输特性及抗噪声效果。研究结果表明,OFDM技术能够有效提升低压电力线通信系统的传输性能,并显著降低通信系统的噪声影响。该技术具有较好的市场应用前景及竞争力。     

基于蒙特卡洛低压电力线信道容量研究

为了有利于设计适当的低压电力线通信设备使之达到更好的有效的数据传输,对低压电力线网络建立模型,优化低压传输信道,对低压电力信道中的脉冲噪声给出了噪声模型.在此基础上研究了支路的数量、支路所带的负载以及支路长度等对信道容量的影响,在负载相同的条件下随着支路数的增加信道容量呈非线性下降趋势,其中室内信道容量下降最大达12兆比特,低压信道容量下降最大达23兆比特,支路负载以及支路长度对信道容量影响不大.结论是低压电力信道容量随着网络拓扑结构的变化呈动态变化.     

低压电力线信道噪声特性分析

主要研究了低压电力线信道噪声特性,首先,介绍了电力线通信（PLC）,然后,针对不同种类的噪声进行了建模,测量并分析了电力线信道的噪声特性。通过实验和仿真,得出了低压电力线信道噪声波形及其特点。     

双芯片电力线通信网络解决方案

介绍了电力线通信网络技术,分析了低压配电网对信号传输衰减大、干扰强、阻抗变化复杂的信道特性,推出了采用改进的正交频分复用(OFDM)技术的双芯片电力线通信网络解决方案。     

基于独立分量分析的电力线通信的研究

针对电力线通信信道的特点,提出了将ICA算法应用于电力线通信系统的方案,并根据电力线的传输特性,构建了系统模型。实验和仿真表明该系统模型能有效地从传输信号中提取弱信号,并进行正确的解码,从而增加了传输距离,而且此系统约束条件少,具有很强的通用性。     

一种改进的蒙特卡罗定位算法研究

针对移动无线传感器网络中节点随机运动的情况,蒙特卡罗定位(MCL)算法有较好的定位精度,但由于MCL方法严格过滤而进行的频繁重采样带来大量计算,加重了节点能量消耗,针对上述情况提出了基于接收信号强度(received signal strength,RSS)的蒙特卡罗定位算法,该算法利用锚节点之间的距离及其测得的移动节点的RSS值来校正移动节点与每个锚节点之间的权值,缩小了传统MCL算法的采样范围。仿真表明,该方法降低了蒙特卡罗方法的采样次数以及通信开销,同时提高了节点定位精度。     

双口形式的戴维宁定理在电路分析中的应用

本文通过网络撕裂法,将电路网络分解为共地连接的有源双口网络和无源双口网络的组合,构造戴维宁定理双口等效网络,分别求出有源双口网络开路电压和无源双口网络的Z参数,根据戴维宁定理的矩阵形式计算双端口电流。文章分析了戴维宁定理在独立电源与含受控源双口网络中的应用,通过算例说明该方法的正确性与适用性。本文的讨论可供讲授电路理论课程的教师参考。     

Dynamic routing network algorithm of low voltage based on link quality

Power distribution network is a dedicated transmission network for power. If you want to use it as communication network, the network traffic will become very complicated. Low voltage distribution network topology is very complex and quite different in different distribution network; and different load leave or input power line will cause a strong performance of channel variability. It is because of these features of low voltage distribution network that it difficult to networking and the network is easily destroyed. This paper presents a dynamic routing algorithm, based on link quality, to improve the reliability of low voltage distribution networks. The algorithm can eventually form an 8-layer structure of the tree topology, and can achieve network self-healing capabilities when the link is broken. The algorithm is suitable for a variety of network physical topology, and finally be able to form a tree structure, thus effectively improving the reliability and system flexibility of communication network. Through the simulation on NS2, we can see the feasibility and network self-healing of the algorithm.     

无源二端口网络的综合

本文论述了双端接阻容负载RC二端口网络转移电压函数的极点与RC阻抗和导纳乘积的零,极点位置分布关系定理.导出了双端接载与等效单端接载网络转移电压函数之间关系的数学模型,利用一次归并和两次分解途径给出了双端接任意阻容负载网络的实现方法.     

基于蒙特卡罗仿真与逆向FTF的复杂系统可靠性分析

针对复杂系统可靠性评估问题,提出了一种基于FTA(故障树)仿真与FMECA(故障模式影响及危害性分析)相结合的逆向FTF综合分析方法,该方法通过故障树的蒙特卡罗仿真计算系统中的重要部件和系统薄弱环节,再利用FMECA有针对性的对重要部件进行详尽分析,提高了可靠性分析的效率,增强了评估的客观性。并以某无人机为例进行了计算和分析,结果表明:该方法对复杂系统可靠性设计具有一定的指导作用和实用价值。     

不均匀多导体传输线的瞬态分析

针对越来越严重的信号畸变和线间耦合问题,应用时域有限差分法（Finite Difference Time Domain,FDTD）建立了不均匀多导体传输线的仿真模型,并通过MATLAB编程对不均匀多导体传输线两端的电压响应进行了仿真分析.在此基础上,理论说明了各端口瞬态响应的波形特点.结果表明了时域有限差分法用于分析多导体传输系统电磁兼容问题的正确性和有效性,为电磁干扰的预测提供了有价值的参考信息.     

Hybrid channel gain prioritized access‐aware cell association with interference mitigation in LTE‐Advanced HetNets

LTE‐Advanced heterogeneous networks deployment is meant to address the increasing demand for quality of service, high data rates and coverage extension. Load balancing is among the primary challenges, especially when the user equipments (UEs) associate with diverse transmission power network tiers using received signal strength. The low‐power network tier's spectrum will be underutilized, and UEs associated with them will be inflicted by interference from the high‐power network tier. The proposed hybrid channel gain prioritized access (HCGPA)‐aware cell association scheme stresses the importance of combined metrics with interference mitigation to simultaneously achieve load balancing and enhance performance among the network tiers. The high‐priority UEs associate with the tier that gives the maximum channel gain being higher than a given threshold. While the low‐priority UEs association is based on the maximum joint metrics (channel gain, channel access probabilities of low‐priority UEs and high‐priority UEs). The HCGPA scheme has 1.72 times the number of UEs connected to low‐power networks, 8% better load balancing fairness, compared with the conventional reference signal receive power and RSRP + 6 dB bias cell associations. Although the susceptibility of HCGPA to interference led to the poor signal to interference to noise ratio (SINR) performance of the cell‐edge UEs, the cell‐centre UEs exhibited the best spectral efficiency performance. Copyright © 2016 John Wiley & Sons, Ltd.     

Distributed localization using mobile beacons in wireless sensor networks

A new distributed node localization algorithm named mobile beacons-improved particle filter (MB-IPF) was proposed. In the algorithm, the mobile nodes equipped with globe position system (GPS) move around in the wireless sensor network (WSN) field based on the Gauss-Markov mobility model, and periodically broadcast the beacon messages. Each unknown node estimates its location in a fully distributed mode based on the received mobile beacons. The localization algorithm is based on the IPF and several refinements, including the proposed weighted centroid algorithm, the residual resampling algorithm, and the markov chain monte carlo (MCMC) method etc., which were also introduced for performance improvement. The simulation results show that our proposed algorithm is efficient for most applications.     

Investigation of Crosstalk and Coupling Effects of Incident Plane Waves in Orthogonal Microstrips in High-Speed Integrated Circuits Using Full-Wave and Quasi-Static Methods

The crosstalk and coupling of the external fields on orthogonal microstrip transmission lines in different layers have significant effects on signal quality in MMIC and PCBs. In this paper the crosstalk is analyzed in detail using both full-wave and quasi-static methods. The used full wave method is mixed potential integral equation method of moment (MPIEMoM). Because of the weak coupling between lines, the effect of the incident plane-wave is studied by applying transmission line theory in a scattered voltage formulation uses quasi-TEM propagation model for each interconnection and the exact distribution of the incident electric field within the layers. Afterward, by using the predetermined lumped circuit model of the cross-region, the effect of coupling between two lines is calculated and then applied to terminal voltages in 1–20 GHz frequency range which results in the final terminal voltages.