The Research Of Third Generation Mobile Communication Base Station Electromagnetic Radiation Measurement And Correlation

In recent years, with the rapid development of wireless communication technology,mobile communication has become an indispensable tool in our dairy life. In order to provide users with better quality communication services, a large number of base stations were built around our living environment and the intensities of electromagnetic radiation become more stronger, which causes public worried about the impact of electromagnetic radiation to base stations. Therefore, it is significant to research the exposure to base stations.In the process of the actual measurement of the electromagnetic radiation from base stations, due to the human factors and the setting of the instrument parameters,the measurement results will be affected. To ensure the accuracy of measurement data,this paper uses the uncertainty of measurement method to study the measurement of electromagnetic radiation by spectrum analyzer. In addition, researches have shown that the exposure level of a base station, associated with traffic and the traffic for mobile communications has a temporal and spatial correlation, which makes it very difficult to accurately predict the radiation value of base stations. In this paper, a method to study the correlation of electromagnetic radiation to the base station based on genetic algorithm is proposed.Our main work is as follows:(1) In terms of measurement instruments research, through the uncertainty of measurement evaluation method to analysis. Firstly, we obtain two kinds of radiation measurement methods by analyzing the working principle of spectrum analyzer and combine with the uncertainty of measurement. Then, the signal generator is used to generate a 3G signal with constant power and measured by spectrum analyzer with different resolution filter bandwidth(RBW). The experiments show that the RBW has no affect the measurement results of “channel-power” method, but the “zero-span”method is adopted, it will bring some errors when the RBW is less than the bandwidth of the input signal. In addition, by comparing with the data of the power meter, the confidence intervals calculated by uncertainty of measurement method is included the range of power meter.(2) In terms of the correlation of exposure to base stations research, we develop a method based on the Genetic Algorithm(GA) to study the correlation of electromagnetic radiation to base stations. Firstly, we use a spectrum analyzer tomeasure the transmission power of the base stations at the different periods of a day.We obtain the analytical expressions for representing exposure with time using GA,and compared with the Gauss Mixture Model(GUM). Finally, an in-depth analyze the correlation of 3G communication base station electromagnetic radiation by function expression. Temporal characteristic : when ??2 hours, the correlation coefficients for3 G were very large, greater than 0.9. It indicates that the have same changing regularity in the coming two hours. Spatial characteristic: we have found a strong cross-correlation of exposure between the base stations located in the same area during a long period, which indicates that the exposure levels of the base stations always rise and decrease simultaneously.