移动通信基站电磁辐射污染特性及控制研究

发布时间：2019-01-01 14:56

【摘要】：移动通信基站是现代通信网络的重要组成部分,在其运行过程中需要发射一定频率和强度的电磁波,这可能会对周边产生电磁环境影响。近年来,我国移动通信事业发展迅猛,形成了三家运营商竞争、三代通信基站共存、多种通信制式网络叠加的局面,其电磁辐射环境问题日益受到公众的关注。因此,为加强对通信基站建设的监管和指导,为运营商的网络建设和环境评价提供依据,开展移动通信基站电磁辐射污染特性和控制研究具有重要的现实意义。针对上述关键问题,本文系统研究通信基站电磁辐射的污染特性及控制技术,研究结果如下：(1)从原理和结构角度,剖析了2G、3G、4G移动通信系统以及基站的技术特点和辐射特征。历代移动通信系统虽然不断提高频谱的利用率,扩大系统的容量,提升数据传输的速率,但本质上都是以蜂窝网络结构为基础,利用电磁波加载并传递信息。(2)采用氦气球监测技术,测量了典型基站在运行期间天线附近空间的电磁场功率密度,分析了天线近距离区域电磁场的变化规律。结果表明：天线正前方功率密度值随距离增加呈现与距离的平方反比下降,而基站运行2G、3G和4G网络在电磁环境影响分布规律和严重程度上未见显著差异。基站运行时,在靠近天线的区域均存在超标的情况,需要划定的电磁控制距离。监测时段的运行状态下,分别在距离天线大约5m～15m处,监测数据即可符合GB8702—2014中相应频段对公众曝露控制限值(40μW/cm2);在离天线约10m～25m处,监测数据可以符合HJ/T 10.3—1996规定的对单个项目的管理约束值(8μW/cm2)。三座基站在全网运行的情况下,功率密度值也随与天线距离增加而减小,分别在距离天线正前方约10m、15m和15m处,符合了GB8702—2014中对公众曝露控制限值(40μW/cm2)。地面监测的功率密度值均远低于规定的限值,与地面电磁环境背景值相接近,故在地面上不需要设置电磁控制距离。根据本文的研究,按照对单个基站功率密度管理约束值的要求,建议典型的移动通信基站电磁控制距离为天线正前方25m。(3)选取了已运行的某基站作为分析对象,验证了基站天线前方电磁控制距离的必要性和合理性。结果表明,由于案例中天线主瓣方向没有保留足够的电磁控制距离,导致监测点的功率密度值超过了限值。最后,结合基站发射天线架设形式及其拟建址周围环境现状逐一分析了电磁控制距离的应用措施。
[Abstract]:Mobile communication base station is an important part of modern communication network. It is necessary to transmit electromagnetic waves of certain frequency and intensity during its operation, which may have an impact on the surrounding electromagnetic environment. In recent years, with the rapid development of mobile communication in China, the competition of three operators, the coexistence of three generation communication base stations, and the superposition of various communication systems, the environmental problems of electromagnetic radiation have been paid more and more attention by the public. Therefore, in order to strengthen the supervision and guidance of the communication base station construction, provide the basis for the network construction and environmental evaluation of the operators, it is of great practical significance to carry out the research on the electromagnetic radiation pollution characteristics and control of the mobile communication base station. Aiming at the above key problems, the pollution characteristics and control technology of electromagnetic radiation from communication base stations are systematically studied in this paper. The results are as follows: (1) from the angle of principle and structure, the paper analyzes 2GG 3G, The technical characteristics and radiation characteristics of 4G mobile communication system and base station. Although successive mobile communication systems have continuously improved the utilization of spectrum, expanded the capacity of the system and increased the rate of data transmission, they are essentially based on the cellular network structure. Using electromagnetic wave to load and transmit information. (2) the electromagnetic field power density in the space near antenna of typical base station is measured by using helium balloon monitoring technique, and the variation rule of electromagnetic field in the near range of antenna is analyzed. The results show that the power density in front of the antenna decreases inversely to the square of the distance with the increase of the range, but there is no significant difference in the distribution and severity of the electromagnetic environment between the 2GN 3G and 4G networks operated by the base station. When the base station is running, the area near the antenna is beyond the standard, and the electromagnetic control distance should be delimited. Under the operating state of the monitoring period, the monitoring data can meet the limit of the public exposure control (40 渭 W/cm2) in the corresponding frequency band of GB8702-2014 at the distance from the antenna about 5m~15m; At a distance from the antenna about 10m~25m, the monitoring data can conform to the management constraint (8 渭 W/cm2) for a single item specified by HJ/T 10.3-1996. When the three base stations are running in the whole network, the power density also decreases with the increase of the antenna distance, which conforms to the public exposure control limit (40 渭 W/cm2) of GB8702-2014 at about 10mt 15m and 15m in front of the antenna, respectively. The power density values of the ground monitoring are far below the prescribed limit values and are close to the ground electromagnetic environment background values, so there is no need to set the electromagnetic control distance on the ground. According to the research of this paper, according to the requirement of power density management constraint value of single base station, it is suggested that the electromagnetic control distance of typical mobile communication base station should be 25m in front of the antenna. (3) A base station that has been operated is selected as the analysis object. The necessity and rationality of electromagnetic control distance in front of base station antenna are verified. The results show that the power density of the monitoring point exceeds the limit because the main lobe direction of the antenna does not retain enough electromagnetic control distance in the case. Finally, the application measures of electromagnetic control distance are analyzed one by one according to the configuration of the base station transmitting antenna and the current situation of the surrounding environment of the proposed site.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN929.5

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