Massage Driven Frequency Hopping System Based On FFT Architecture And FPGA Implementation

As a kind of spread spectrum technology,Frequency hopping has good anti-jamming and anti-fading ability.However,receiver of the frequency hopping system needs to do the frequency hopping synchronization,which leads to the complexity of the receiver.This complex receiver structure not only limits the increase of skip speed,but also limits the selection of modulation mode.This will reduce the information rate of frequency hopping system.This paper proposes a message driven frequency hopping system based on IFFT / FFT architecture,and designs a new mapping method for this frequency hopping communication system.Then,the performance analysis of the key technical of the system and the behavior level simulation of baseband waveform are completed.Firstly,taking frequency hopping technology as a starting point,the principle and key technologies of frequency hopping system are briefly introduced,and the advantages and problems of frequency hopping system are explained.In order to improve these problems of traditional frequency hopping system,this paper first introduces the principle and implementation scheme of message driven frequency hopping system,and introduces two improved systems of message driven frequency hopping system,enhanced message driven frequency hopping system and anti-jamming message driven frequency hopping system This paper also introduces the principle and key technologies of frequency hopping system based on FFT architecture,and gives an application example of frequency hopping system based on FFT architecture.Then,three kinds of frequency hopping systems are modeled and compared.Secondly,based on the former part,this paper proposes a message driven frequency hopping system based on FFT architecture,introduces the system design and key technologies of message driven frequency hopping system based on FFT architecture in detail,and proposes a bit synchronization method for this system,which is verified by simulation.For the proposed system,this paper designs a new mapping method,orthogonal grouped binary frequency shift keying(OG-2FSK),and introduces the specific mapping process with the traditional mapping mode binary phase shift keying(BPSK).The message-driven frequency hopping system based on FFT architecture is modeled,and the transmission efficiency and bit error rate are compared with the traditional frequency hopping system.It is concluded that the message driven frequency hopping system is to use BER performance as the expense of exchange for the improvement of transmission efficiency.Then,a mathematical model of the message driven frequency hopping system based on the FFT architecture is proposed.The bit error performance of the OG-2FSK mapping and BPSK mapping of the system under the AWGN channel and the time selective fading channel is derived.Then,the results of the simulation are verified.Finally,based on the previous parts,this paper designs the FPGA hardware implementation scheme of message driven frequency hopping system based on FFT architecture,introduces the module division of transmitter and receiver in detail,including the function of each module,interface design and simulation results,and gives the overall design and simulation results of transmitter and receiver.The results of behavior-level simulation show that the baseband waveform generated by the fft-based message-driven frequency-hopping system based on Verilog language in this paper is correct and can normally complete the functions of framing,modulation,synchronization,demodulation,which proves that the design of this system can complete the basic communication functions.