| With the development of mobile communication systems,the quality of service and user experience have gradually become the primary goal of designing the mobile communication system.However,during the construction and using of the mobile communication systems,interference has always been a negative factor which affects the performance of the communication network.And interference will impact on handover,congestion,system capacity and cell coverage.Therefore,it is necessary to analyze and study the interference generation principle of the mobile communication system,perform investigation according to different characteristics.At last by using appropriate optimization methods to reduce inter-system interference and optimize the wireless network.This thesis combined with the practical work experience,analyzes and studies the problem of interference detection and optimization in Long Term Evolution(LTE)system.Firstly,this thesis outlines the LTE system,analysis the characteristics of LTE system,studies the compositon of the LTE system and the key technologies.This thesis systematically studies the interference problems in LTE system and mobile communication systems.The causes and characteristics of interference are described.The interference is classified according to frequency,system,network element and interference source.The interference detection and optimization methods are studied.This thesis analyzes the principle and classification of interference generation in LTE systems.The author summarizes the interference problems in LTE systems and classifies them into intra-system interference,inter-system interference and external interference according to the causes.For the interference in LTE system,the principle of interference types such as GPS loss of lock interference,frame out-of-synchronization interference and ultra-long interference is studied.For inter-system interference,the principles of interference types such as spurious interference,blocking interference and harmonic interference are studied separately.The principle of interference caused by external causes,such as radio and television Mutichannel Multipoint Distriubtion Services(MMDS)interference and atmospheric waveguide interference are further analyzed.Then,this thesis analyzes the interference waveform and waveform recognition algorithm of LTE system.The Physical Resource Block(PRB)level interference characteristics of interference types such as overlapping coverage interference,spurious interference,blocking interference,intermodulation interference and harmonic interference are analyzed.And then the corresponding waveform characteristics are studied.Waveform recognition algorithms based on waveform characteristics are studied,including roll-off type interference recognition,overall uplift type interference recognition and partial carrier high type interference recognition.In addition,this thesis analyzes and studies the interference troubleshooting and optimization of LTE systems.Taking Time Division-Long Term Evolution(TD-LTE)system as the research object,this thesis studies the troubleshooting ideas and processes of interference problems.For the intra-system interference,the analysis and processing methods of GPS loss of lock interference,frame out-of-synchronization interference and ultra-long interference are studied.For inter-system interference,the analysis and processing methods of spurious interference,blocking interference and intermodulation interference are studied respectively.Finally,the frequency sweeper equipment commonly used in the process of interference investigation and optimization is analyzed and analyzed.The principle of the equipment,precautions for use and the method of use are introduced.Finally,this thesis analyzes and studies the interference investigation and optimization of LTE system in actual work.For the interference in LTE system,this thesis analyzes the troubleshooting and optimization of GPS out-of-synchronization interference and frame configuration error interference.For LTE inter-system interference,the pseudo base station interference problem and the detection and optimization of spurious interference are studied.For external interference,the analysis and study of radio and television signal interference and private signal amplifiers lead to the investigation and optimization of interference problems.In order to bring the advanteges of LTE system into better play and achieve faster and smooter data service experience,it is necessary to study the interference problems in LTE systems and optimize the wireless network which can provide higher-speed,broadband and higher quality of service communication services for every customer. |
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