DME Impulse Interference Mitigation Method Based on Joint Wavelet Transform and Whitening of Residual Interference

To mitigate the deleterious influence of Distance Measure Equipment (DME) impulse signal on the receiver of L-band Digital Aeronautical Communications System 1(L-DACS1), a new DME interference suppression method based on joint Wavelet transform and whitening of residual interference was proposed in this paper. Firstly, the received time-domain signal was transformed into wavelet-domain via wavelet transform at the Orthogonal Frequency Division Multiplexing (OFDM) receiver. Secondly, the wavelet coefficients of DME impulse signal were extracted according to their differences with those of useful OFDM signal. Then, the DME impulse interference signal was reconstructed and eliminated from the received signal in time domain. Finally, to avoid the burst errors of demodulator, the residual impulse interference was converted into white Gaussian noise by using the de-interleaver and inverse orthogonal transformer. Simulation results showed that the system performance can be improved over 5dB by using the proposed method in this paper than the conventional pulse blanking method under the condition of the same bit error rate（10^-2）. Therefore, the link transmission reliability of the L-DACS1 system can be improved significantly with the proposed method.