Research On NR Downlink Broadcast Channel Link And Interference Signal Detection Technology

With the continuous development of 5G NR technical standard protocol,5G mobile communication network has been gradually constructed.The arrival of 5G era brings us higher network speed experience and more convenient life experience.The physical broadcast channel PBCH in 5G NR is one of the most important downlink channels,which is used to broadcast the key system information MIB necessary for the mobile user terminal to access the wireless communication system.Like 4G,5G is also a mobile communication network based on OFDM system,which will affect the normal operation of mobile communication system in the face of increasingly complex communication environment such as various interference signals.In order to improve the performance of interference detection in OFDM system based broadcast channel link,it is of great significance to study and improve the interference detection algorithm in broadcast channel link.Therefore,the design and implementation of NR downlink broadcast channel link simulation platform and the research of interference signal detection technology are the main contents of this thesis.Firstly,this thesis analyzes the downlink physical channel in NR,and designs a link simulation platform of NR physical layer downlink broadcast channel based on OFDM system according to 3GPP R15 NR physical layer standard protocol.The platform uses C++ language and adopts modular design.The platform is mainly divided into base station sender and user receiver.It realizes the coding and sending of main system information block MIB by base station sender and receiving and demodulating of coding information by receiver.Secondly,the interference signal detection in NR downlink broadcast channel link is studied.Based on the broadcast channel link simulation platform based on OFDM system,the interference signal detection algorithm in frequency domain is studied.Based on mean and standard deviation,CME,FCME and segmented CME algorithm,the threshold value of interference detection in frequency domain is analyzed and studied,and an improved CME interference signal detection algorithm is proposed.The algorithm has low complexity,good detection performance and easy implementation.