Coexistence Research Of IMT System For 5G

With the development of information technologies,wireless data traffic is rapidly increasing,and there will be more and more different requirements of communication systems.In order to meet the requirements about different coverage,performance and capacity in future mobile communication systems,we should find more potential resources in different frequency bands.Therefore,it is of great reference value to consider coexistence of IMT(International Mobile Telecommunications)system and other standard wireless systems in different frequency bands,as well as study the inter-system interference.This thesis focuses on the coexistence study of IMT system.Specifically,it includes interference analysis between IMT system and aeronautical mobile services,IMT system and GSM(Global System for Mobile Communication)system,as well as 5G NR(the 5th-Generation New Radio)systems.According to the different characteristics of these systems,we applied deterministic analysis or Monte-Carlo simulation method respectively for study,in order to give some corresponding coexistence schemes.For the coexistence of the IMT system and the aeronautical mobile service,we utilized deterministic analysis method.In the specific analysis process,aeronautical mobile service includes two kinds,i.e.,radio altimeter and aeronautical mobile telemetry ground station.For coexistence study of IMT system and radio altimeter,the interference value was obtained by calculating the pathloss and antenna gain.We conclude that the isolation distance should be more than 6.766km in the departing and landing scenario while no extra isolation measures is required in the smooth flight scenario.For coexistence study of IMT system and aeronautical mobile telemetry ground station,they can coexist when the isolation distance is more than 5.45km.For the coexistence of IMT system and GSM system,the Monte-Carlo system level simulation method is adopted.Since the NB-IoT(Narrow band Internet of Things)system has become an evolutionary system after the 4G system,it is regarded as a typical system,which coexists with the existing GSM system.We studied the two-way interference between them.In the urban macro scenario,we obtained uplink results and downlink results through simulation.Among them,it includes six situations with different user density.After analyzing these simulation results,we also give some frequency isolation suggestions about coexistence of NB-IoT system and GSM system.For the coexistence of two 5G NR systems,we used the same simulation method as aforementioned to study the interference in the urban macro scenario.The thesis introduced the relevant contents of NR system model in detail,including pathloss model,building penetration loss model,antenna and beamforming model,transmission power control model and L2S(Link Level-to-System Level)interface mapping.According to simulation results,two NR systems need to keep ACIR(Adjacent Channel Interference Ratio)greater than 12.5dB for coexistence.