| Mobile internet services are developing rapidly and user scale of those mobile internet services is expanding continuously.People are exposed to the electromagnetic radiation of mobile terminals while using various services.Due to the different data transmission characteristics of mobile internet services,the wireless signal transmission modes are quite different.Thus,mobile phone electromagnetic radiation changed a lot when using different services.Currently,researchers mainly consider the antenna characteristics and path loss in the prediction of electromagnetic radiation intensity of mobile phones,so it is impossible to accurately predict the electromagnetic radiation of mobile phones in different services.On the other hand,the research on the human body absorption of mobile phone electromagnetic radiation is mainly carried out through simulation according to radiation characteristic of antennas,without considering the influence of antenna construction mode on the electromagnetic radiation propagation environment,resulting in a large difference between the evaluation results and actual situation.In view of the above problems,the main work and innovation of this paper are as follows:(1)Proposed a mobile phone average electromagnetic radiation prediction method based on service transfer interval distribution.This method establishes a probabilistic model of data transmission interval time for mobile internet services by analyzing the time characteristics of mobile internet services.Based on the probabilistic model of interval time,duty cycle of mobile phone transmitted signal is obtained,and the average electromagnetic radiation intensity of mobile phone under different services is predicted by duty cycle.By collecting a large number of QQ user data,this paper established mobile phone QQ messages interval time probability model,and predicts mobile phones signal duty cycle and average intensity of electromagnetic radiation according to the model when using QQ,the average error rates between experimental measurements and prediction results of duty cycle and average electromagnetic radiation intensity are 12.3 % and 6.4 % respectively,shows that the method can accurately predict average intensity of electromagnetic radiation.(2)Propose a prediction method of mobile phone radiation specific absorption based on antenna construction mode.In this method,a mobile phone simulation model is established according to different antenna types and the construction mode of the antenna in the mobile phone,and the simulation model is adjusted according to specific absorption rate(SAR)measurement data of real mobile phones.The adjusted model is used to predict human body specific absorption rate of electromagnetic radiation from mobile phones.This paper set up four kinds of mobile phone models,and do simulation using these models combined with human body model which can adjust gesture,the simulation results show that SAR value of the mobile phone model with plastic fuselage monopole antenna is largest.In addition,human hand has strong absorption to electromagnetic radiation when using mobile phones,which leads SAR value of other parts of human body significantly reduced.(3)Develop a remote measurement and control software for electromagnetic radiation in order to improve the efficiency of experimental measurement.This software not only supports electromagnetic radiation measurement of common network signal with predefined measurement parameters,but also supports the custom measurement parameters and measurement process,which means you can control the spectrum analyzer to carry out measurement and save results automatically.In addition,this software can monitor the realtime measurement data,network connection state and power supply state.In this paper,the software is used for the measurement of different scenes.Compared with manual measurement,using this software can achieve more accurate measurement result and shorter measurement time. |
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