【摘要】：移動通信基站是現(xiàn)代通信網(wǎng)絡(luò)的重要組成部分,在其運行過程中需要發(fā)射一定頻率和強度的電磁波,這可能會對周邊產(chǎn)生電磁環(huán)境影響。近年來,我國移動通信事業(yè)發(fā)展迅猛,形成了三家運營商競爭、三代通信基站共存、多種通信制式網(wǎng)絡(luò)疊加的局面,其電磁輻射環(huán)境問題日益受到公眾的關(guān)注。因此,為加強對通信基站建設(shè)的監(jiān)管和指導,為運營商的網(wǎng)絡(luò)建設(shè)和環(huán)境評價提供依據(jù),開展移動通信基站電磁輻射污染特性和控制研究具有重要的現(xiàn)實意義。針對上述關(guān)鍵問題,本文系統(tǒng)研究通信基站電磁輻射的污染特性及控制技術(shù),研究結(jié)果如下：(1)從原理和結(jié)構(gòu)角度,剖析了2G、3G、4G移動通信系統(tǒng)以及基站的技術(shù)特點和輻射特征。歷代移動通信系統(tǒng)雖然不斷提高頻譜的利用率,擴大系統(tǒng)的容量,提升數(shù)據(jù)傳輸?shù)乃俾?但本質(zhì)上都是以蜂窩網(wǎng)絡(luò)結(jié)構(gòu)為基礎(chǔ),利用電磁波加載并傳遞信息。(2)采用氦氣球監(jiān)測技術(shù),測量了典型基站在運行期間天線附近空間的電磁場功率密度,分析了天線近距離區(qū)域電磁場的變化規(guī)律。結(jié)果表明：天線正前方功率密度值隨距離增加呈現(xiàn)與距離的平方反比下降,而基站運行2G、3G和4G網(wǎng)絡(luò)在電磁環(huán)境影響分布規(guī)律和嚴重程度上未見顯著差異�；具\行時,在靠近天線的區(qū)域均存在超標的情況,需要劃定的電磁控制距離。監(jiān)測時段的運行狀態(tài)下,分別在距離天線大約5m～15m處,監(jiān)測數(shù)據(jù)即可符合GB8702—2014中相應頻段對公眾曝露控制限值(40μW/cm2);在離天線約10m～25m處,監(jiān)測數(shù)據(jù)可以符合HJ/T 10.3—1996規(guī)定的對單個項目的管理約束值(8μW/cm2)。三座基站在全網(wǎng)運行的情況下,功率密度值也隨與天線距離增加而減小,分別在距離天線正前方約10m、15m和15m處,符合了GB8702—2014中對公眾曝露控制限值(40μW/cm2)。地面監(jiān)測的功率密度值均遠低于規(guī)定的限值,與地面電磁環(huán)境背景值相接近,故在地面上不需要設(shè)置電磁控制距離。根據(jù)本文的研究,按照對單個基站功率密度管理約束值的要求,建議典型的移動通信基站電磁控制距離為天線正前方25m。(3)選取了已運行的某基站作為分析對象,驗證了基站天線前方電磁控制距離的必要性和合理性。結(jié)果表明,由于案例中天線主瓣方向沒有保留足夠的電磁控制距離,導致監(jiān)測點的功率密度值超過了限值。最后,結(jié)合基站發(fā)射天線架設(shè)形式及其擬建址周圍環(huán)境現(xiàn)狀逐一分析了電磁控制距離的應用措施。
[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.
【學位授予單位】：浙江大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN929.5

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本文編號：2397718