Research On FPGA Implementation Of Link-16 Data Link Anti-jamming Enhanced Waveform

Tactical data links can achieve battlefield situation sharing,command and control,and weapon collaboration,playing a very important role in modern information warfare.Link-16,as the most representative tactical data link,has advantages such as strong anti-jamming ability and good confidentiality,and is widely used in various weapon platforms.With the rapid development of information technology,electromagnetic jamming has become more complex and powerful,and the anti-jamming technology of traditional Link-16 data links has become difficult to cope with;In addition,the theoretical maximum transmission rate of traditional Link-16 is only 238kbps,which cannot meet the needs of modern warfare for image and video transmission services.Therefore,thesis improves the traditional Link-16 data link,proposes an anti-jamming enhanced waveform transmission scheme and a high-speed mode waveform,builds a link compatible with multiple rate modes,and conducts hardware platform implementation and performance testing based on Field Programmable Gate Array（FPGA）.The main content of the paper is as follows:Firstly,based on the traditional Link-16 timeslot structure and two timeslot packaging formats,Standard Double Pulse（STDP）and Packed 2 Double Pulse（P2DP）,thesis provides two transmission schemes for waveform and header to enhance anti-jamming ability;A high-speed enhanced transmission scheme is proposed based on the Packed 4 Single Pulse（P4SP）packaging format.Secondly,thesis analyzes four data assisted frequency offset estimation algorithms for the channel environment with low SNR and high frequency offset,and gives an algorithm scheme for the secondary estimation of frequency offset based on cross correlation.The performance of this algorithm is compared with L&R algorithm and Fitz algorithm through simulation.The results show that the anti-jamming enhanced waveform based on P2DP packaging format in the additive white Gaussian noise（AWGN）channel,When the carrier frequency is 18GHz and the relative motion speed is 4 Mach,when the normalized root mean square error（RMSE）of the frequency offset achieves10^-3,the performance of the secondary estimation cross correlation algorithm is improved by about 1.9d B compared to the Fitz algorithm and about 5d B compared to the L&R algorithm.Thirdly,thesis designs a technical scheme for encoding,modulation and demodulation of anti-jamming enhanced waveforms,as well as jamming detection and suppression.The enhanced waveform adopts Low Density Parity Check（LDPC）encoding instead of RS encoding,using Hadamard orthogonal spread spectrum with Minimum Shift Keying（MSK）modulation or Fourth Order Continuous Phase Modulation（4CPM）modulation,corresponding to two different soft demodulation algorithms:soft despreading and soft output Viterbi;In response to frequency domain jamming,the waveform receiver adopts jamming detection methods based on overlapping windowing and Forward Consecutive Mean Elimination（FCME）algorithm and suppress it by extinguishing it;For time-domain jamming,the FCME algorithm is used to detect the jamming and suppress it by extinguishing it.The paper conducted performance simulations on enhanced waveforms under different conditions,and the results showed that under strong suppression jamming,compared with traditional waveforms,the BER performance of enhanced headers,enhanced waveforms based on STDP and P2DP packaging formats can be improved by up to 11d B;The high-speed enhanced waveform based on P4SP packaging format has increased the transmission rate by about 17.5 times compared to traditional waveforms.Fourthly,thesis comprehensively considers processing delay and resource consumption,and designs an FPGA implementation scheme for enhancing waveform,and conducts implementation and performance testing.On the baseband board card based on the XCVU11P FPGA chip of Xilinx Company,the performance of the enhanced waveform link is measured in different scenarios.The results show that compared with the MATLAB floating point data simulation,the measured performance of the enhanced waveform link falls back within 0.5d B,indicating that the link has a high implementation accuracy and can meet the actual application requirements.