Research And Simulation On The Anti-jamming Technique Of UAV Data Link

The opportunity for combat is fleeting in modern warfare,each combat unit of the war is connected by the data link as a whole,so that the real-time tactical intelligence can be shared among each combat unit.Therefore,the reliability of information transmission is the important guarantee of obtaining the victorious war in the unmanned aircraft vehicle（UAV）data link,so the anti-jamming performance of the UAV data link must be improved to ensure the reliability of data transmission.Firstly,the commonly used spread spectrum technique about the anti-jamming in the UAV data link communication is analyzed by the paper,the two key techniques,M-ary spread spectrum and frequency hopping OFDM,are analyzed and simulated.M-ary spread spectrum has additional coding gain compared with direct sequence spread spectrum under the same RF（Radio Frequency）bandwidth.When the BER（bit error rate）is 10^-5,the anti-jamming performance of M-ary（512,8）spread spectrum can be increased about 3.5dB compared with the direct sequence spread spectrum under the environment of additive white Gauss noise（AWGN）channel.The frequency hopping OFDM technique is analyzed,and the comparison of using single carrier to imitate OFDM and IFFT operation of single frequency point is simulated,which proves the rationality of the implementation of IFFT in the frequency hopping OFDM.Secondly,a anti-jamming scheme called single orthogonal code frequency hopping orthogonal frequency division multiplex（SOCFH-OFDM）modulation is proposed,which is based on spread spectrum and frequence hopping OFDM,and the principles of transmitter and receiver module of the SOCFH-OFDM scheme are analyzed.The anti-jamming performance of the SOCFH-OFDM scheme is analyzed theoretically,and the simulation is carried out on the MATLAB platform.Simulation results show that,when the BER is 10^-5,the anti-jamming performance of the SOCFH-OFDM system is enhanced about 1dB compared with the orthogonal code time division multi-subchannels spread spectrum modulation（OC-TDMSCSSM）system under the wideband noise jamming and AWGN channel,and about 1dB higher than that of the OC-TDMSCSSM system under the environment of partial-band jamming and AWGN channel.Finally,based on the spectrum sensing and OC-TDMSCSSM technique,a anti-jamming scheme called spectrum sensing M-ary frequence hopping orthogonal frequency division multiplex（SSMFH-OFDM）is proposed,and the principle of the SSMFH-OFDM scheme is analyzed.The simulation results show that,when the BER is 10^-5,the anti-jamming performance of the SSMFH-OFDM scheme,whose spectrum sensing module is reduced at this time,is about 3dB higher than that of the OC-TDMSCSSM scheme under the environment of wideband noise jamming and partial-band jamming respectively.At the same time,the simulation results show that,due to the advantage of the spectrum sensing technique which is used to determine the frequency hopping points of the SSMFH-OFDM scheme at the transmitter,when the BER is 10^-5,the anti-jamming performance of the SSMFH-OFDM scheme is enhanced about 2d B compared with the SSMFH-OFDM scheme whose spectrum sensing module is removed under the environment of partial-band jamming and AWGN channel.Another advantage of the SSMFH-OFDM scheme is that the spectrum sensing technique is not required at the receiving module,so the complexity of the receiver of the UAV data link is reduced,which is mainly due to the orthogonality among the OFDM subcarriers.