GMSK Frequency Hopping Communication System Design And Its FPGA Implementation

In the modernized information battlefield,in response to the complicated electromagnetic environment and escalating electronic warfare technology,an urgent need for a communication technology can ensure the effectiveness and security of communications between the two military parties.Frequency hopping communication is kind of spread spectrum communication,and it has excellent anti-multipath fading,anti-band interference and channel blocking ability.As soon as it appeared,it was widely used in various strategic and tactical communication systems and became an important anti-interference means.In view of the application background of the military tactical missile,in order to ensure the confidential,secure and anti-intercept high-speed transmission of the wireless communication data of the tactical missile,a scheme of GMSK(Gaussian Minimum-shift Keying)frequency hopping communication system is designed and implemented with FPGA.Based on the characteristics of frequency hopping communication carrier pseudo random jump and increase the communication bandwidth,it is difficult to intercept the data to the enemy in the unknown carrier hopping law,ensure the anti-interference and reliability of tactical missile communication.The transmission rate of data is effectively improved by using the excellent spectrum characteristics of GMSK modulation and the utilization of high frequency band.This thesis mainly studies and designs some implementations and functional indexes of TDMA,FH sequences,frequency synthesizer,GMSK modulation,GMSK demodulation and so on.Among them,for the GMSK modulation,this thesis uses the scheme that the GMSK baseband phase is added to the frequency hopping carrier phase,and solves the cosine for the sum of the phases.It can not only realize the frequency hopping but also better ensure the phase continuity of the modulated signal and save the hardware resources.GMSK frequency hopping communication system based on FPGA,including time division multiple access module,GMSK modulation module,frequency hopping module,GMSK demodulation module and so on.The system uses the Verilog HDL hardware description language implemented in Xilinx ISE14.7.It uses a top-down approach to designing inputs and simulating verification with ModelSim software,so that ensures the correct functioning of each module of the system.Finally,debug the hardware card,and test the communication performance of the system through the error code analyzer.The experimental results show that the BER performance of the system is good,which has certain application value and reference value for the tactical missile's anti-jamming and secret communication.