A multiple-feature-based recognition algorithm for OFDM signals and subcarrier modulations

Aiming at the problem of low accuracy of traditional methods in the recognition of OFDM signals and their subcarrier modulation modes, a multi-feature based OFDM signal and subcarrier modulation recognition algorithm is proposed. By extracting the fourth-order cumulant, sixth-order cumulant, and constellation diagram features of the signal, featuresHs1,Hs2, andHs3are constructed. Using the fourth-order cumulant and the first two features, the recognition of OFDM, 8PSK, BPSK, and QPSK signals is realized. An improved K-means++ clustering algorithm is further designed to determine the clustering centroids of the constellation diagrams and complete the classification and identification of 16QAM, 32QAM, 64QAM, 128QAM and 256QAM signals based on the constructed features. The simulation results show that the algorithm has good recognition performance, and improves the recognition accuracy by 15% at SNR=5dB compared with the traditional algorithm for high-order MQAM signals, which can be effectively applied to the modulation recognition of OFDM signals and their subcarrier signals.