Suppression Technology Research On The Intensive DME Pulse Interference Based On Wavelet Transform

L-band Digital Aeronautical Communications System 1(L-DACS1) is the broadband candidate technology for the future L-band digital aeronautical communications system.L-DACS1 employs Frequency Division Duplex(FDD) and Orthogonal Frequency Division Multiplexing(OFDM) technology. As unused spectrum is very scarce in L-band, L-DACS1 makes use of the gaps between adjacent channels used by the Distance Measuring Equipment(DME). So the OFDM receiver is interfered by the DME signal inevitably. In order to suppress the DME pulse interference, an airborne receiver scheme of L-DACS1 based on wavelet transform is proposed in this paper.Firstly, according to L-DACS1 system protocol specifications, system parameters and the operating principle of L-DACS1 are introduced.Secondly, the principle and signal model of DME are given. In the typical interference scenario, the impact of DME interference on airbone receiver of L-DACS1 is analyzed in detail.Thirdly, conventional approaches of DME pulse interference suppression, including pulse blanking and clipping, are introduced and their influences on the Bit Error Rate(BER)performance of L-DACS1 system are verified with simulation.Lastly, DME pulse interference suppression method based on wavelet transform is proposed in this paper. The DME pulse signal can be reconstructed based on wavelet transform denoising method, and then the time-domain pulse interference elimination can be used to suppress DME pulse interference. The simulation results show that the proposed receiver scheme in this paper can significantly improve the link transmission reliability under the condition of Additive White Gaussian Noise(AWGN) channel and multipath channel.