共查询到20条相似文献,搜索用时 62 毫秒
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本文对调频信号隧道覆盖技术进行了研究,从信源、近端机、远端机、天馈等四个环节进行了技术分析,得出系统覆盖所需功率的计算公式,并从实践得出调频信号隧道覆盖时需考虑的重要因素,最后介绍了杭州调频信号隧道覆盖一期项目的情况,并对项目实施过程出现的问题进行了总结。 相似文献
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隧道内调频广播信号的优质覆盖,一方面要实现隧道内一定强度的无线信号覆盖,另一方面还需要考虑尽量降低直放站间以及隧道内外可能存在的同频干扰问题。济南开元隧道的调频广播覆盖利用了济南的调频同步广播系统,设计并实现了隧道内调频广播同步覆盖,有效解决了直放站间尤其是隧道内外的同频干扰问题,获得优异的收听效果。 相似文献
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本文主要是结合山区隧道的无线覆盖情况,对移动通信无线信号在高速公路隧道中的覆盖技术进行分析.主要从隧道内分布方案的实施、隧道外投射方案的实施和隧道泄漏电缆方案的实施三个方面展开论述. 相似文献
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近年来,随着社会经济的发展,私家车得到了普及发展且隧道的数量与日俱增,但是隧道内的信号并不是十分好,因此为满足社会大众的需要,有效解决隧道内数字电视信号的覆盖问题刻不容缓.同时隧道内数字电视信号覆盖的方式主要有两种,即天线和泄漏电缆的方式.通过对这两种覆盖方式进行理论上的分析和实际的测量比较,简单的介绍了其各自的优势和劣势以及所能够适用的主要场合. 相似文献
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介绍了隧道中广播电视信号的测试与分析方法,通过移动路测采集数据、Excel表单统计数据、Matlab软件仿真场强分布,全面掌握隧道中调频广播(FM)、移动电视以及CMMB信号的覆盖情况,为地铁等其他封闭区域内的信号覆盖测试提供参考。 相似文献
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高铁3G覆盖难点技术研究 总被引:2,自引:2,他引:0
文章针对高铁的位置更新问题提出LAC和RAC规划方法,对存在的移动切换和重选问题提出过渡区等方法并对切换算法提出建议,对高铁长隧道以及特大桥难点覆盖问题提出解决办法,对于山区和海域铁路的信号覆盖规划有一定的参考价值。 相似文献
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Mathilde Benveniste 《Wireless Networks》1996,2(4):289-296
Once a subscriber unit served by a microcell initiates a call, it must remain in the coverage area of the microcell long enough to complete call set up and hand-off functions. This restricts the minimum size attainable by a microcell. This paper derives the relationship between the microcell size, the call processing time, and the probability that a subscriber unit, initiating a call, will remain inside the microcell coverage area for at least the duration of call processing. Under simple assumptions, time spent in the coverage area of the microcellbefore andafter call initiation have the same cumulative density function, which is derived in this paper for traffic conditions encountered in highway and metropolitan settings.This paper is based on a contribution to the ETSI GSM2 Standards, Ronneby, Sweden, September 1991 [1]. 相似文献
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A joint street microcell/office picocell model is used to evaluate a digitally enhanced cordless telecommunications (DECT) system providing outdoor as well as indoor radio coverage from indoor radio ports. The indoor DECT network is able to provide seamless communication within the city area with no capacity loss, provided that the majority of calls are originated from indoors 相似文献
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随着GSM网络用户数的不断增长,话务量不断攀升,话务密度也随之增加,高话务热点地区如雨后春笋,这种条件下,对于北京、广州等经济发达、人口密集城市,室外大站站间距已达到二、三百米。显然,单纯依靠室外宏蜂窝不可能完全解决热点地区容量问题,而室内微蜂窝覆盖技术作为一种有效解决容量问题的手段而得到越来越多的关注。 一、 室内微蜂窝覆盖系统的概述 为了解决不断增加的用户数量与有限的频率资源之间的矛盾,GSM移动通信网络由80年代的大区制,逐步发展为现在的以宏蜂窝为主的小区制。为了进一步提高系统容量,在采用1x3、MR… 相似文献
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TD-LTE室内覆盖是网络规划、建设的重要环节.本将TD-LTE 3种室内覆盖规划方案划分为三大类方式:分别是通过室外基站、室内分布系统和室内微基站进行室内覆盖.通过室外基站进行室内覆盖具有节省投资,建网速度较快,室内室外覆盖联合规划等优点.通过有源和无源分布系统进行室内覆盖适合于对业务数据速率和业务量要求较高,需要深度覆盖的场所,是大多数中大型场所的室内覆盖解决方案.通过室内微基站进行室内覆盖主要适合小型的办公娱乐场所,以及住宅弱信号覆盖楼层,具有传输接入简单,建网成本等优点. 相似文献
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Cellular and point-to-multipoint wireless communication systems use fan-beam antennas for sector coverage from the central station. The ratio of the azimuth-to-elevation half-power beamwidth typically ranges from two for sites requiring low-gain antenna values to 25 or greater for sites covering large cells. This article presents an approximate formula for the antenna directivity of the fan-beam antenna using two parameters to describe the azimuth pattern shape, and two parameters for the elevation pattern. The directivity formula presented includes minor lobes. A variation of the fan-beam directivity formula is presented for the omnidirectional antenna. The directivity formula presented in this note is developed from separable-pattern functions, and uses a pattern-shape parameter in addition to the half-power-beamwidth value 相似文献
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Majhi A.K. Agrawak V.D. Jacob J. Patnaik L.M. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2000,8(5):610-614
We propose a new coverage metric for delay fault tests. The coverage is measured for each line with a rising and a falling transition, but the test criterion differs from that of the slow-to-rise and slow-to-fall transition faults. A line is tested by a line delay test, which is a robust path delay test for the longest sensitizable path producing a given transition on the target line. Thus, the test criterion resembles path delay test and not the gate or transition delay test. Yet, the maximum number of tests (or faults) is limited to twice the number of lines. In a two-pass test-generation procedure, we first attempt delay tests for a minimal set of longest paths for all lines. Fault simulation is used to determine the coverage metric. For uncovered lines, in the second pass, several paths of decreasing lengths are targeted. We give results for several benchmark circuits 相似文献