Research On Non-cooperative Recovery Technology For New Radio Physical Layer Bit Stream In 5G Mobile Communication

At present,the mobile communication system has evolved to the fifth generation(5G).In order to achieve performance indicators in different business scenarios,the signal system of the 5G system is quite different from the previous generations,and the configuration is flexible.In application scenarios such as protection of major events,antiterrorism,and stability maintenance,the supervision of mobile communication equipment has always been an indispensable part.At the same time,with the rapid development and evolution of military communication technology,the concepts and technical scope of communication countermeasures and electronic warfare have already extended to 5G and other new communication system signals.However,most of the current research and applications related to 5G signal processing follow the process of cooperative communication,which is not applicable to the above-mentioned equipment management and military communication application scenarios.Therefore,it is of great significance to study 5G signal detection and signal analysis from a non-cooperative perspective.In response to the above problems,this article uses the communication reconnaissance method in the field of electronic countermeasures,combined with the time-frequency domain characteristics of 5G signals to carry out research.Focus on the analysis and improvement of the synchronization block frequency search method and time-frequency synchronization algorithm involved in the access process,and propose a physical layer code stream recovery method on this basis.The main contents of the work are as follows:1.For the problem that the air interface access process in cooperative communication requires a large amount of search work on the synchronization raster,a fast estimation method of symbol length based on the characteristics of the time-domain pulse envelope is proposed.Combined with the frequency domain characteristics of the primary synchronization signal(PSS),the direct judgment of the center frequency of the synchronization block is realized,and a large amount of search work for the synchronization raster is avoided.2.Based on the completion of the frequency point judgment of the synchronization block,the algorithm is improved for the problem of the poor detection effect of the coarse timing point estimation algorithm in the scene of large frequency deviation,and the performance is compared and analyzed by simulation.The frequency offset estimation algorithm is improved based on the characteristics that the 5G sync block is 4 consecutive symbols in the time domain.Based on the completion of the system time-frequency synchronization,the secondary synchronization signal(SSS)is detected,and a fast detection method based on its phase characteristics is proposed,which realizes the rapid acquisition of the physical-layer cell identifier(PCI).3.After completing the time-frequency synchronization and PCI acquisition,the physical layer bit stream recovery work is performed.After analyzing the key algorithms involved in the channel estimation algorithm and the recovery process,a recovery method of the physical layer code stream of the broadcast information master information block(MIB)is proposed.At the same time,based on the establishment of the data channel simulation link,the performance of the channel estimation algorithm is simulated and compared.4.An experimental environment was built based on a universal mobile communication signal receiver,and the actual 5G signal was intercepted and analyzed to complete the acquisition of broadcast information,which verified the feasibility of the scheme.