共查询到17条相似文献,搜索用时 93 毫秒
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对国内电信运营企业3G技术体制进行了比较,介绍了3G VPDN专网的定义和概念,分析了建立3G VPDN的准备工作及通信建立过程,并对其安全性、优缺点进行了描述;对3G VPDN专网和常见的通信方式进行了比较,探讨了3G VPDN专网在无线电监测网中的应用。 相似文献
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一个复杂的网络,必须使用先进的网络管理工具来管理,以最大程度发挥其效益。网络管理工具可以为用户提供主动式的智能化管理,能有效地预测、隔离、诊断和解决问题,使网络可靠、有效地工作。本文主要介绍网管原理、网络管理工具的功能特点及其在监测网中的应用。 相似文献
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根据系统需求,全国有线电视监测网使用的数据库系统是Oracle数据库,该系统突出的优势是分布式、稳定、可移檀性。 相似文献
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深圳市科立讯数据技术有限公司 《中国无线电》2007,(10):62-63
0引言信息技术的高速发展带来通信产品的日益繁荣,目前市场上的网络通信方式大致分为有线和无线两类。像手机、蓝牙产品、GPS、对讲机等就是在无线领域中最常用的通信工具。在无线通信过程中,通信的 相似文献
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分析了目前软件无线电在测量仪器领域发展的新趋势,并以N5530S测量接收机系统为例介绍了软件无线电在测试仪器及系统中的应用原理及方法。 相似文献
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本文结合各种实际测试介绍了罗德与施瓦茨公司的手持式频谱仪R&S FSH在发射机与天馈线测试、无线电干扰查处以及电磁兼容诊断测试中的应用。 相似文献
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The instability of operational channels on cognitive radio networks (CRNs), which is due to the stochastic behavior of primary users (PUs), has increased the complexity of the design of the optimal routing criterion (ORC) in CRNs. The exploitation of available opportunities in CRNs, such as the channel diversity, as well as alternative routes provided by the intermediate nodes belonging to routes (internal backup routes) in the route-cost (or weight) determination, complicate the ORC design. In this paper, to cover the channel diversity, the CRN is modeled as a multigraph in which the weight of each edge is determined according to the behavior of PU senders and the protection of PU receivers. Then, an ORC for CRNs, which is referred to as the stability probability of communication between the source node and the destination node (SPC_SD), is proposed. SPC_SD, which is based on the obtained model, internal backup routes, and probability theory, calculates the precise probability of communication stability between the source and destination. The performance evaluation is conducted using simulations, and the results show that the end-to-end performance improved significantly. 相似文献
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Bangwon Seo 《Signal processing》2011,91(11):2623-2629
We consider a single-user multiple-input multiple output (MIMO) transmission from secondary base station (SBS) in cognitive radio network where there is one primary user to which spectrum is licensed. It is assumed that coexistence of secondary network is allowed if interference power from the secondary network measured at primary user (PU) can be kept below a given threshold. In this paper, joint design problem of precoder and receiver is treated using mean-squared error (MSE) criterion between transmitted signal and its estimate at the receiver. Due to constraint on interference power measured at the PU, it is not possible to find an optimal solution in closed form. Therefore, a suboptimal solution with low complexity is proposed in closed form. Simulation results show that the MSE and bit error rate (BER) performances of the proposed scheme are 1.5-4.0 dB better than those of a conventional capacity-maximization scheme when the received signal-to-noise ratio (SNR) is high, and they converge to their lower bounds, i.e., those of an MSE-based scheme without considering the PU interference constraint, as the received SNR increases. 相似文献
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仪器设备是无线电监测站开展工作的重要物质条件和技术基础,是在新形势、新任务下,提高监测水平,加大对空中电波监管力度的重要“武器”,其工况质量会直接影响到监测站各方面的工作。随着我国无线电技术和业务的迅猛发展,为了分析技术投资成本,提高无线电监管与服务质量,保障无线电事业的可持续发展,必须对仪器设备使用期间的技术状况和效率进行科学的分析和研究,以保证各级监测站的技术建设效益。 相似文献
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介绍了联通公司的CDMA1X分组域VPDN联网技术,并针对此项技术在无线联网方面的应用作了分析.对无线电监测系统中移动车与固定站应用此项技术的方式、方法及其优越性作了讨论. 相似文献
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现代的世界经济在很大程度上依赖于货物的运输。海洋运输航线上货轮的密度一直在增加,而渔船、渡船、挖泥船等船舶又使航线上船只密度过大的问题更加严重。这种情况是随着海运业的蓬勃发展所产生的,它的产生又导致了一系列问题,如航海人员生命安全所受到的威胁、货物安全所受到的威胁和生态环境所受到的威胁等。因此,可靠的海运控制和监测就越来越重要,世界各国都在使用专业的无线电设备来进行海运船只的监控,这些设备称为VTS(Vessel Tramc Service,船舶交通服务)系统。 相似文献
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1 引言
随着信息技术的迅速发展,无线通信设备的种类和数量迅速增加,呈现出大功率、高频率、宽频段、智能化的用频特点,电磁环境变得日益复杂,频谱资源管理面临新的挑战。电磁环境监测是频谱资源管理的有效手段和必要基础。目前,我国已经形成了以固定监测站为主,可搬移监测站(含车载)、便携式监测设备为辅的无线电监测网体系。 相似文献