The Electromagnetic Radiation Research Of LTE Mobile Communication Base Station

Base stations provide mobile communication services and produce electromagnetic radiation.With the increasing number of base stations,it is very important to predict and evaluate the electromagnetic radiation of base stations accurately.At present,LTE base station is the largest mobile communication base station,and which is divided into FDD-LTE base station and TD-LTE base station.At the same time,the exposure level of base station is closely related to the traffic characteristics it carries.In the traditional prediction methods of electromagnetic radiation exposure level of base station,Poisson distribution is mainly used as the traffic model.But in recent years,with the continuous growth of data services,it is difficult to describe the traffic load with Poisson distribution and predict the electromagnetic radiation of LTE base station accurately.In view of the existing problems,the main contents and innovative work of this paper are as follows:(1)For the FDD-LTE base station,this paper proposes a prediction method of electromagnetic radiation of base station based on the batch arrival traffic model.According to the time-frequency resource allocation mechanism of different downlink physical channels in FDD-LTE base station,this method analyzes the random characteristics of the number of simultaneously occupied sub-channels by batch arrival queuing theory,and establishes the calculation method of time-frequency resource utilization of PDSCH channel.At the same time,the calculation method of time-frequency resource utilization of PDCCH channel and other fixed transmission signals is given.Prediction of the average electromagnetic radiation level of the base station based on the total time-frequency resource utilization of the downlink.In this paper,the theoretical calculation value of time-frequency resource utilization rate and the prediction value of electromagnetic radiation are verified in different periods of the day.The experimental results show that the average relative deviation rate of the time-frequency resource utilization rate and the prediction result of electromagnetic radiation obtained by this method is 8.82% and 5.24% respectively,which shows the effectiveness and accuracy of this method.(2)For TD-LTE base station,this paper proposes an average electromagnetic radiation prediction method based on the traffic model of heavy tailed distributed.By analyzing the heavy tailed distribution characteristics of packet arrival,the heavy tailed distribution traffic model is established to calculate the average transmission power,and the mobile network traffic is theoretically correlated with the electromagnetic radiation exposure level of the base station.The average transmission power of the base station is substituted into the Friis transmission formula,and theaverage electromagnetic radiation intensity of the base station at different positions in line-of-sight is obtained.In this paper,the average electromagnetic radiation of different distance in the direction of sight distance of the base station is tested in different time periods.The experimental results show that the average relative deviation rate between the predicted value of electromagnetic radiation and the measured result is 4.2%,which shows that the method can accurately predict the average electromagnetic radiation of TD-LTE base station.