Research On Physical Layer Of Tactical Data Link Link-11 And Modulation Identification

Tactical data links are usually used for command and control of specific forces in a specific area of operation. Link-11, which is also called TADIL A, is a kind of tactical data links. It employs network communication technology and standard information formats for digital information exchange.Firstly, the communication protocols of Link-11 are introduced in this thesis. Based on these, a point to point simulation model of the tactical data link is established, including coding and decoding, modulation and demodulation, frequency estimation and so on. Then, FFT demodulation is used for signal demodulation of Link-11. Simulation results show that the demodulation method has a good performance under imperfect frequency estimation. At the last parts of the thesis, it mainly researches the multiple signal identification which is based on decision-theoretic and high-order cumulants. By extracting instantaneous properties of the signal, signal classification among 2ASK,4ASK,2FSK,4FSK,2PSK,4PSK and Link-11 is completed. In the later study, based on high-order cumulants, all the cumulant values of 2ASK,4ASK,2FSK,4FSK,2PSK,4PSK are derived and a kind of identification method for Link-11 signal is proposed. Because 2FSK and 4FSK have the same cumulant value, a new method for identifying the two signals is proposed in this thesis. Simulation results show that this method is effective.