Research On Enhanced Technology Of Link-16 Communication Waveform

Link-16 data link is a tactical information distribution system that integrates communication,navigation,command control and identification,holding capabilities of large capacity,anti-jamming,high rate,and high security.In recent years,with the development of electromagnetic interference technology,the limited anti-jamming tolerance of Link-16 data link is difficult to tackle the increasing threat of electromagnetic interference.The"blind"anti-jamming method based on traditional spread hopping and error correction coding appears more and more passive.Moreover,when using Link-16to exchange tactical and command information between aircrafts,if only single antenna is used for communication,the signal might be blocked by the airframe in some scenarios,causing serious decline in communication quality or even communication interruption,failing to achieve full airspace communication.Hence,this thesis studies the enhanced technology of Link-16 communication waveform from three aspects:Link-16 waveform anti-jamming enhanced receiving technology,Link-16 waveform enhanced technology based on TDCS,and Link-16 full airspace waveform enhanced technology.The organization of this thesis is described as follows.The first chapter introduces the research background of this thesis,summarizing current research status of Link-16 waveform anti-jamming methods and full airspace communication,and presents the research content of the thesis.The second chapter introduces the Link-16 system,and builds a simulation link based on the standard Link-16 waveform.The third chapter studies the traditional Link-16 waveform anti-jamming enhanced receiving technology,countering typical suppression jamming such as single tone/multi-tone jamming,linear frequency modulation jamming,noise frequency modulation jamming and noise blocking jamming.Traditional Link-16 system applies a high-speed frequency hopping system,where the sample of interference signal at each frequency is rather sparse.,resulting in incomplete windowing of the vanilla overlap windowing algorithm.The performance of jamming suppression will also be affected due to spectrum leakage of possible high-power interference signals.Hence,this chapter designs an adaptive interference detection and suppression algorithm.The algorithm switches to single-channel detection and suppression mode when high power jamming appears.Compared with traditional interference suppression algorithms,this one balances the loss of signal-to-noise ratio and the suppression of interference signal spectrum leakage.Simulation results show that the adopted anti-jamming enhanced receiving technology has significantly augment the resistance of suppressive jamming for traditional Link-16waveforms.Under severe jamming conditions where the jamming-to-signal ratio is over40d B,the bit-error-rate performance can still maintain a tight approximation of a none jamming scenario.The fourth chapter studies the Link-16 anti-jamming communication waveform based on TDCS,given the circumstances where the transmitter can acquire the interference signal's spectrum from the receiver.The consideration here is to further improve the anti-jamming capability of Link-16,This chapter presents the TDCS waveform scheme and processing flow compatible with the traditional Link-16 pulse structure.For the double-pulse format,if the two pulses suffer from different jamming conditions,the combined pattern of traditional Link-16 waveform cannot handle TDCS waveform.Therefore,this chapter proposes a double-pulse TDCS waveform receiving algorithm based on combining correlation values.Simulation results show that the proposed TDCS-Link-16 enhanced waveform greatly improves the anti-jamming performance of the system link,while preserves the traditional Link-16 data rate and time slot structure.When the BER reaches the order of 10^-6,the performance of the TDCS waveform is improved by about 5.5d B.Chapter 5 focuses on the problem that the single-antenna Link-16 system is affected by the airframe block during air-to-air and air-to-ground communication,which lead to declining of communication quality.This chapter considers 7 typical communication scenarios,and proposes to install antennas on both the back and belly of the aircraft,utilizing onboard dual antennas for air-to-air or air-to-ground communication.Here a two-transmit,two-receive multi-antenna transmission scheme based on space-frequency block code and orthogonal frequency division multiplexing technology is adopted,and a frame format that adapts to the Link-16 time slot structure and system characteristics is further designed.Simulation results show that the proposed multi-antenna transmission scheme can effectively solve the communication link interruption caused by the blockage,while keeping the Link-16 time slot structure unchanged.It can also overcome the influence of inter-symbol interference caused by multipath propagation delay when communicating with ground equipment.Finally,Chapter 6 summarizes the full thesis and briefly describes further in-depth research.