| GSM is the most successful and widely used 2G mobile communication standard in the world nowadays. it created the precedent of digital communication and promoted the development of the globalization of the communication industries; As the "quasi-4G" technology of mobile communication which evolved from 3G technology, LTE will become the technical backbone of the communication industries in 10 years. In order to maintain the quality of communication and information security, it’s essential to identify and monitor the information of base station for GSM/LTE downlink transmission. This thesis systematically designed and implemented the algorithm of synchronization and demodulation for GSM/LTE standard system downlink broadcast channel.The key technologies of GSM/LTE downlink system was briefly analyzed in this thesis, including physical channel, logical channel, frame structure and GMSK modulation of GSM system and OFDM. MIMO technology, frame structure and resource structure of LTE system. As for the modular design of GSM receiver, this thesis proposed a modified algorithm of FCCH detection based on the Goertzel algorithm in the synchronization module, the algorithm and process of GSM demodulation module was introduced by dividing it into 4 submodules including channel estimation, matched filtering, channel equalization and channel decoding modules. As for the modular design of LTE receiver, this thesis analysed and designed the algorithm of PSS detection and SSS detection, divided PBCH demodulation module into 6 submodule including OFDM demodulation, channel estimation, resource demapping, MIMO decoding, QPSK demodulation and bit-level procecing modules to design the algorithm. In addition, the thesis did some hardware simulation and joint debugging of the GSM/LTE receiving system, analysed the simulation results by using CCS and MATLAB, and finally showed the results in the PC interface.The multi standard wireless mobile communication base station information identify system designed in this thesis can do the real-time monitoring of broadcast information of GSM base station with the purpose of determine its legitimacy, as well as the cell information identification of LTE. |
