Research On Key Technologies Of Spectrum Auditing In LTE System

With the advancement of the times and the development of communication technologies,production and living have generated great demands for high-bandwidth,low-latency wireless communication services.This phenomenon has led to the emergence of a variety of advanced wireless communication systems and increasingly strained spectrum resources.In addition,5G technology has entered an important stage in critical technological breakthrough and the development of standards.It has brought new requirements and challenges to the requirements,planning,configuration,and usage of related spectrum resources.Therefore,it is necessary to carry out research and audit on candidate frequency bands.In particular,it is important to audit and evaluation the existing spectrum resource occupied by LTE systems.The thesis mainly studies the key technology of spectrum resource auditing in the fourth generation mobile communication system,and discusses the technology of spectrum information acquisition involved in spectrum auditing from two perspectives.One is to use spectrum detection algorithm directly to obtain the spectrum information of the LTE system when channel decoding cannot be performed on LTE system.Another method is to obtain spectrum information by decoding the LTE physical channel when the physical channel of the LTE system can be decoded.This thesis first analyzes the spectrum audit from the perspective of system auditing,and discusses the development status of spectrum auditing around the system auditing factors.The thesis studies different related technologies based on different spectrum audit objectives.When spectrum occupancy information is used as the spectrum audit target,the paper studies spectrum detection techniques.When spectrum utilization efficiency is used as the audit target,the paper studies carrier modulation information acquisition techniques.Firstly,the classical spectrum detection algorithm is introduced,and the principles of these spectrum detection algorithms are fully analyzed and discussed.Then,this thesis presents a cooperative spectrum sensing algorithm based on phase difference,introduces the principle of the algorithm in detail,derivate the probability density formula of signal phase difference under different channel conditions,and adds the cooperative spectrum sensing algorithm technology to improve the detection performance.Then,we carry on the simulation analysis to evaluate our sensing scheme.Finally,we focused on the acquisition of LTE spectrum information when channel decoding to the LTE system can be performed.LTE spectrum information is obtained by decoding each channel of the LTE physical layer.In order to acquire information in the PDCCH channel,we must analyze the PBCH,PCFICH,Therefore,the channel structure and resource mapping modes of these channels are analyzed and the decoding scheme is designed for each channel.Finally,a blind detection scheme of DCI information in the UE-specified search space without C-RNTI information is purposed.