| With the gradual maturity of the commercialization of the fourth generation mobile communication technology,the number of long term evolution(LTE)mobile terminals has increased rapidly year by year.The popularity of mobile terminals has brought more and more convenience to people's life on the one hand,and on the other hand,it also increased the possibility of private information exposure.Therefore,it is of great practical value to configure a control system which can interrupt the communication of target terminals in many confidential situations.The purpose of this thesis is to build a control system which can acquire the target identity information and has terminal recognition function,and optimize its control channel detection algorithm so as to improve the operation efficiency and stability of the control system.At present,the research of LTE control system mainly focuses on the protocol stack and signaling process,and seldom considers the optimization of channel demodulation and decoding algorithm,so as to improve the efficiency and stability of the control system.This thesis focuses on optimizing some control channel detection algorithms involved in LTE control system,ensuring accurate decoding of air interface messages and timely interaction of uplink and downlink signaling,which can improve system stability and reduce delay by improving the speed of signal detection and decoding,and improving the deficiencies of existing control schemes so as to improve the control efficiency.The main research contents are as follows:Firstly,the implementation scheme of LTE control system is described,and the key time-consuming steps of the existing scheme are analyzed.On this basis,the optimization direction of control channel algorithm in the key steps of management and control is given.Secondly,in order to improving the efficiency of message detection and decoding in control channel of control equipment,the main synchronization subsection overlapping correlation detection algorithm of LTE system and antenna port number detection algorithm based on Kalman autoregression are used to improve the efficiency of control system in the process of air interface message decoding.The computational complexity of cell synchronization process and the delay caused by blind detection of physical broadcast channel(PBCH)message decoding are reduced,and the good antinoise and anti-frequency offset performance of the algorithm are verified.Thirdly,the dummy call trigger network fallback is used to force the target terminal to reset the cell to obtain the identity information of the target terminal,and the optimized complete control scheme is given.A semi-dynamic threshold preamble detection algorithm based on root sequ ence grouping is proposed to improve the detection efficiency of random access requests by virtual base stations,this algorithm reduces the execution complexity of control schemes and improves the stability and accuracy of system target recognition.Finally,the control channel optimization algorithm and the complete control scheme are verified by the test.The validity and executability of the control channel algorithm and the control system are validated by acquiring the measured data of the air interface through the software defination radio(SDR)equipment and combining the test results of the mobile phone and the Pioneer software. |
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