PHS、3G和WLAN共用室内分布系统分析

介绍了PHS、3G和WLAN三个无线业务使用同一套室内分布系统实现3种信号同时覆盖;首先讨论了这三个业务各自的室内覆盖系统及其具体设计参数等;然后介绍了共用系统中有源设备的合路情况;分析了共用系统中存在的功率匹配问题,得到了相关结论。对各工作频带间的相互干扰问题做出了相关分析并给出了部分解决方案。     

多无线系统环境下室内覆盖优化研究与实施

在室外宏基站信号覆盖的情况下,如何提高室内信号覆盖率,提高服务质量是各营运商争夺市场的有效手段,本文对室内多无线系统的合路问题进行讨论,并结合案例分析给出合路建议.     

综合室内覆盖系统中干扰分析

随着无线覆盖的完善,综合室内覆盖系统依靠一套分布系统就能满足多制式信号覆盖的要求并逐渐成为室内覆盖的主要方式.文章具体分析了多制式系统共存时各系统间的相互干扰情况与抑制干扰的途径.     

综合室内覆盖系统中干扰分析

随着无线覆盖的完善,综合室内覆盖系统依靠一套分布系统就能满足多制式信号覆盖的要求并逐渐成为室内覆盖的主要方式.文章具体分析了多制式系统共存时各系统间的相互干扰情况与抑制干扰的途径.     

无线数字电视信号对CDMA2000干扰的查找与分析

随着科技的进步．各式无线网络遍布城区,特别是随着3G移动基站的大规模建设,无线电干扰也日趋复杂。本文的案例即为cDMA2000上行频率受到MuDS无线电视信号发射设备干扰。MuDS全称是无线多路分米波分配系统（MultichannelUHFDistributionSystem）,其工作频率段为470MHz～800MHz。平均发射功率为5～8W．可覆盖半径10～15公里．是广电部门用于村村通工程无线数字电视覆盖的一种传输手段。     

哈尔滨地铁1号线工程公用通信隧道区间无线覆盖中继设置测算

介绍了地铁通信工程利用宽带POI设备对三大运营商通信网络信号进行合路处理后实现无线覆盖的基本方式,结合哈尔滨地铁1号线工程实例,重点阐述了不同的网络制式信号通过漏泄电缆在隧道区间传输和覆盖时,中继距离的计算方法.     

千兆宽带全光室内远端覆盖

针对室内无线保真信号覆盖不均匀、无线带宽和入户宽带速率不匹配的问题，分析了室内无线宽带覆盖的现状及传统技术。介绍了以光纤为传输介质，光网关加远端延伸设备的覆盖技术。并用实例验证了千兆入户宽带使用该技术方案后，室内无线信号覆盖均匀、速率能够达到千兆级别。     

LTE FDD&CDMA室内分布系统合路改造方案探讨

首先对中国电信现有室内分布系统资源及结构进行了说明,对2100MHz频段内LTE FDD在不同室内场景下的链路预算及天线的覆盖能力进行了分析。最后给出了LTE FDD的系统合路改造方案。     

MCI在上海F1国际赛车场中的应用

介绍了上海F1国际赛车场移动通信室内覆盖的业务种类、话务量及系统设计方案,重点分析了通过采用优质的合路平台MCI和收发分缆传输对解决互调干扰的意义.     

漏泄通信系统在地铁中的应用

地铁内信号的覆盖问题始终困扰运营商,目前行之有效的方法是搭建一套漏泄通信系统.此系统首先应用合路平台设备(POI)技术;其次采用漏缆传输方式对地下空间进行信号覆盖;再次通过有线方式将各运营商的信号传送到地铁站内的各自基站,系统信号经POI合路后通过地铁内的漏缆把信号发送出去,从而实现地铁内信号的覆盖.最后将研究成果应用到某运营商地铁线路的网络建设中,为后期地铁无线网络设计提供了思路.     

咸阳数字MMDS系统规划思路

介绍咸阳数字MMDS系统的总体规划思路，在咸阳广电网络中心机房建设数字MMDS前端系统．通过1550nm模拟光传输系统将QPSK调制信号送到3个发射台，从而覆盖整个咸阳地区。从网络无线覆盖规划到系统结构组成、前端系统、用户端接收及同频干扰抑制等各个方面进行具体介绍。     

470～510MHz频段无线抄表系统干扰共存

现行射频规范限制470～510MHz频段无线抄表系统不能适应电力网络新的通信速率和覆盖范围需求.如何调整相关射频规范,在保障邻频先用通信业务不受干扰的前提下,有效提升无线抄表系统的通信能力成为目前亟待解决的问题之一.针对该问题,首先分析国内450～566MHz频段频谱划分情况.随后根据国家电网3种无线抄表系统的射频参数,通过确定性计算和射线追踪仿真的方法,研究所述无线抄表系统和邻频广播电视系统、CDMA450系统、铁路列调系统、FDD LTE系统之间的干扰共存情况.最后给出相关射频规范的修改建议.     

基于FPGA动态信号产生器设计

主要介绍了研制动态5 MHz信号产生器的背景及利用FPGA实现动态5 MHz信号产生器的原理和方法。介绍了所应用的DDS基本原理,说明了信号发生器的内部结构和软件流程。给出了信号产生器关键参数的计算方法。简要介绍了器件选择依据,最后给出了仿真波形。通过试验,验证设计达到了预期目的,充分显示了DDS与FPGA相结合的好处。     

Experimental Study of a Fixed WiMAX Network at 2.62 GHz

Field measurements of signal strength is one of the basic techniques for coverage determination of a cellular network. In this paper, we report on the experimental study of the signal strength measurements in a typical worldwide interoperability for microwave access network operating at 2.62 GHz installed for fixed wireless access in the district of Greater Noida, Uttar Pradesh, India. The experimental data are analyzed for deriving characteristic parameters of the radio propagation environment. The characteristic parameters include path loss exponent and standard deviation of shadow fading. Having derived the characteristic parameters, we propose path loss models for the cellular network. The study also aims at the determination of network coverage for the given system parameters. Results and their analysis are utilized for network planning and optimization of the system parameters for the installed cellular network.     

Implementation of Filter Bank–Based RF Transceiver for TV White Space

This paper presents a general‐purpose design scheme of a filter bank (FB)–based radio frequency (RF) transceiver that operates across the entire ultra‐high frequency (UHF) TV band from 470 MHz to 698 MHz and complies with the TV white space (TVWS) regulatory requirements. To this end, an intermediate frequency (IF) band‐pass filter (BPF) with a sharp skirt characteristic is considered as a solution for handling the incoming signals from a baseband modem. Specifically, an FB‐based BPF structure with four ceramic resonator filters that effectively rejects unwanted signals is proposed to extract a desired signal in the TV band. Achievable data rates of a cognitive radio system (CRS) employing the proposed FB‐based RF transceiver at the application layer are investigated in both wired and wireless environments. The service coverage of the CRS network is measured according to several modulation and coding schemes (MCSs) of the CRS. The results show that the coverage of a wireless network in a nearly open area can be extended by more than 9.3 km in the TVWS. Experimental results also confirm that the proposed FB‐based RF transceiver is adequate for utilization in TVWS applications.     

A Proposed Equivalent Channel Power Delay Profile for a Millimeter Wave Wireless OFDM System and Optimum Guard Interval Evaluation in a Built-Up Area Propagation Scenario

Vertical plane launching ray tracing method has been applied for a real urban scenario and the delay characteristics of received signals in the overall coverage area have been extracted. Using these parameters, an equivalent channel power delay profile (ECPDP) has been introduced for the overall coverage area. For a millimeter wave wireless OFDM system, the optimum guard interval length which maximizes the mean of signal to interference and noise ratio has been simulated. Also, using the proposed ECPDP, the optimum guard interval length has been analytically extracted and compared with the simulated one.     

浅析CDMA网络密集市区覆盖解决方案

密集市区无线传播环境复杂,用户众多,是CDMA网络需要重点覆盖的区域.本文分析了密集市区无线传播环境,根据特定环境下的CDMA网络覆盖特点,提出了各种区域的覆盖解决方案.对于商业中心区应结合室外基站和室内分布系统加强深度覆盖.高层建筑通过基站分裂小区,安装特定的天线,天线上仰等方式进行大部分楼层的覆盖,电梯、建筑物底层、地下停车场通过室内分布系统完善覆盖.密集住宅小区通过在小区外围设站,或者通过射频拉远方式对住宅区进行覆盖,并结合天线美化与伪装,直放站信号源和分布系统进行覆盖.密集城中村通过基站、直放站等信号源结合室外分布系统,选取合适的天线及安装位置进行覆盖.     

Interactive computation of coverage regions for wirelesscommunication in multifloored indoor environments

For indoor wireless communication systems, radio frequency (RF) transceivers need to be placed strategically to achieve optimum communication coverage at the lowest cost. Unfortunately, the coverage region for a transceiver depends heavily on the type of building and on the placement of walls within the building. Traditionally, therefore, transceiver locations have been selected by human experts who rely on experience and heuristics to obtain the optimum (or near-optimum) placement. This paper describes an interactive software system that can be used to assist in transceiver placement. It is intended to be easy to use by individuals who are not experts at wireless communication system design. After the user has selected transceiver locations within a graphical floor plan, the system interprets the floor plan and uses simple path loss models to estimate coverage regions for each transceiver. These regions are highlighted, enabling the user to assess the total coverage. This paper describes the methodology used to compute the coverage regions for multifloored buildings and discusses the effect of interference sources. The resulting system is expected to be useful in the specification of indoor wireless systems     

基于谱估计的噪声调频信号检测方法研究

对干扰信号的频谱特征进行精确测量和分析是实施有效的电子反干扰(ECCM)的重要步骤.通过对噪声调频干扰信号的频谱特征分析,提出采用合适的功率谱估计方法来检测噪声调频信号的主要频谱特征参数.利用MATLAB/Simulink仿真软件分别建立了噪声调频信号源和谱估计方法的系统模型,研究了系统采用不同的谱估计方法和参数设置的情况下所能够达到的检测精度,并根据仿真结果分析比较了不同谱估计方法的性能.     

高校教学楼无线网络建设解决方案

本文以对主要教学楼4-6层进行无线新建为建设内容,进行网络建设方案设计。在新建的过程中,需要充分考虑和原有校园网无线网络的融合性,避免重复投资。建设的关注点,也要从单纯的在教学楼实现简单的无线信号覆盖基础上进一步进行无线信号的带宽利用率和信号稳定性保障、全网漫游等。