Research On Key Technology Of Link-16 Data Link In Fading Channels

In the scene of the modernized information warfare,rapid and accurate information exchange between communication parties in complex environments is the key to win the war.To ensure the accuracy and effectiveness of the information interaction,it is necessary to lower the impact of the external environment on the communication link,and to enhance the communication solidity and the information transmission efficiency.However,the problem of information warfare is that the communication platform is relatively far away,and it requires to withstand fading and interference from the ground,building,and carrier movement to transmit the signal,which greatly increases the difficulty of the receiver to acquire information and the effect of the received reception.Therefore,in an effort to improve the efficiency of information transmission,to realize safe transmission of signals and make sure of the accuracy of demodulation at the receiver side,to find a reasonable solution for multipath fading and doppler effect is in need.This paper focuses on Link-16 data link as the research object,and based on the analysis of Link-16 communication performance,two targeted solutions are proposed from the perspectives of data link application technology and data link transmission process,which effectively reduce the error rate of the receiver and improve the efficiency of information transmission.The main research contents are as follows:First,the physical model of the Link-16 data chain was constructed,and the anti-fading ability and the anti-jamming ability of Link-16 data link was analyzed from the four levels of the network structure,the time slot structure,the message format and the communication system.The key technologies involved in the Link-16 data link,including multi network structure,communication protocol,four international standard packaging formats,and the generation of physical waveforms,were emphasized.Moreover,the simulation verification was conducted on the transmission effect of Link-16 data link signals in common electromagnetic environments,and modular analysis and evaluation were carried on the error code results of the data link.Next,a truncated code shift keying method is proposed to address the problem of low transmission rate and frequency band utilization of the Link-16 data link on the information warfare platform,based on an improved Logistic mapping method for spatiotemporal chaotic sequences using the one way coupled map lattice model.This improves the frequency band utilization of the data link system.The algorithm uses the distribution characteristics of the improved Logistic map to generate chaotic sequences,and uses mirror symmetry to process the spread spectrum sequences.The overall performance and feasibility of the proposed scheme are analyzed through complexity calculation,band utilization calculation and bit error rate simulation,and the bit error performance of the proposed scheme is analyzed using the specific COST207 channel for reference.Finally,considering the issue of low accuracy in Doppler frequency offset estimation of Link-16 signals using traditional estimation algorithms,a joint frequency offset estimation algorithm is proposed based on the frequency offset range of Link-16 signal in this paper,which can be applied in low signal-to-noise ratio scenarios.The working frequency band of Link-16 data link is L band,which is higher than many other common communication frequency bands.Therefore,the signal has to suffer from doppler effect in the transmission process of complex military environment.The traditional frequency offset estimation algorithm is difficult to achieve high estimation accuracy within the range of Link-16 frequency offset.So in the algorithm proposed in this article,a pilot insertion structure was first designed based on the special signal frame format of the Link-16 data link,and the cramer rao bound of the doppler frequency offset estimation value under this structure was derived.Then,a two-step joint frequency offset estimation algorithm was proposed.By comparing simulation analysis with other scholars’ proposed schemes,the estimation accuracy,estimation range,and error rate performance of this scheme were verified.