Analysis of multipoint transmission at higher frequencies using 3‐D ray tracing

The target of this article is to analyze the impact of multipoint transmission e.g. joint transmission (JT) in an outdoor microcellular environment at 15 and 28 GHz frequency through simulations. The impact of the JT threshold i.e. the threshold for switching between the single and multipoint transmission mode is also analyzed in this article. For this research activity, a “sAGA” MATLAB based 3‐D ray tracing tool is used for the simulation purpose. The received signal power and throughput are used as a performance metrics for the analysis. The simulation results show that the JT from two transmission ports provides up to 12.46% and 17.78% of relative throughput gain with respect to the transmission from single port at 15 and 28 GHz, respectively. The multipoint transmission with certain decibels (dBs) of JT threshold is found to be more efficient compared with the undefined JT threshold. In the light of simulation results, the JT is found as a promising technique for compensating the propagation loss at higher frequencies, and especially in a critical handover region the multipoint transmission helps in making a smooth handover.     

高原地区数据中心海拔因素对供电系统设计的影响

本文分析了高原海拔和空气等环境因素对数据中心高低压变配电系统、通信电源系统、后备柴油发电机组等电源设备的影响,对高原数据中心的供电设计进行了探讨,提出高原地区数据中心电源设计中应对高原特殊环境采用的应对技术措施。     

基于WiFi技术的煤矿井下应急救援无线通信系统设计分析

本文通过基于WiFi技术来设计煤矿井下应急救援无线系统,重点从建立无线通信信道以及无线通信系统的角度加以总结.     

基于声光频移技术的激光通信系统研究

设计了一套基于声光频移技术的激光通信系统。与一般相干通信系统比较,该系统在信号发送端完成了光波的频移以及不同频率光波的光学拍频,而在接收端直接探测拍频信号的中频成分。最后完成通信速率为3MHz的实验验证,达到了设计效果。     

一种基于相异度的接收天线选择算法

对于多输入多输出系统天线选择算法而言,穷尽搜索算法能够达到最优的性能,但包含较多矩阵运算,计算复杂度较高。而传统基于相关度和相似度的天线选择算法虽具有较低计算量,但损失了较大的容量性能。针对这一问题,以容量性能为目标,提出了基于相异度的接收天线选择算法,分析了不同相异度下所提选择准则对系统性能的影响。与传统相关度和相似度天线选择算法相比,所提算法有效降低了计算复杂度,改善了系统的容量性能,仿真结果表明:所提算法具有较好的系统性能,适用于实时通信系统。     

网络入侵检测方法研究

本论文从网络安全现状出发,介绍了入侵检测的原理和基本技术,随后就企业如何在已有网络的基础上建立一个可扩展的网络入侵检测系统以及整个方案的设计、实现作了相关阐述,同时强调了安全意识在网络安全中的重要性。     

低压配电系统智能化设计

提出了一种低压配电系统的智能化设计方案，介绍了其组成原理，并给出了采用双CPU的一个应用实例。此外，还择要阐述了相关元器件选择、抗干扰措施等问题。     

一种偏振成像探测系统的测量精度检测

分析偏振测量原理得到偏振成像偏振度的测量绝对误差。通过偏振测量实验,分别计算了偏振光的真实偏振度和偏振成像的偏振度,求出偏振度的绝对误差,与理论分析结果相符合。检测了实验中使用的偏振成像探测系统的测量精度。     

A Plasma‐Etching Process Modeling Via a Polynomial Neural Network

A plasma is a collection of charged particles and on average is electrically neutral. In fabricating integrated circuits, plasma etching is a key means to transfer a photoresist pattern into an underlayer material. To construct a predictive model of plasma‐etching processes, a polynomial neural network (PNN) is applied. This process was characterized by a full factorial experiment, and two attributes modeled are its etch rate and DC bias. According to the number of input variables and type of polynomials to each node, the prediction performance of the PNN was optimized. The various performances of the PNN in diverse environments were compared to three types of statistical regression models and the adaptive network fuzzy inference system (ANFIS). As the demonstrated high‐prediction ability in the simulation results shows, the PNN is efficient and much more accurate from the point of view of approximation and prediction abilities.     

基于大系统方法的上行CDMA蜂窝系统性能分析

结合大尺度和小尺度衰落,采用大系统分析方法对CDMA蜂窝系统上行链路的性能进行分析。首先分析了小区内多址干扰和小区间干扰的情况;其次推导出了通过匹配滤波器后的信干噪比值,该值只与小区负载、用户功率、信道增益有关;最后分析了系统的误码率、吞吐量和频谱效率,并通过仿真验证了分析的准确性。仿真结果发现,随着小区负载的增大,系统的误码率增大,吞吐量下降,但频谱效率有所提高。