Research and Simulation Experiment on HF Communication Noise Reduction Method Based on Wavelet Transform
Ming Zhu Yang, Xin Zhang, Wencheng Zhang, Peidong Xia, Haoxuan Lu, Chunpeng Wang · 2024
HF communication is an important way of medium and long-distance wireless communication, and it is an indispensable military communication mode. Due to the characteristics of multipath interference, fading, and Doppler frequency shift in HF channels, to improve the transmission quality of HF signals, this paper applies wavelet transform to HF denoising. Simulate AWGN and HF channels using MATLAB to analyze the denoising effect of wavelet transform. The simulation results show that wavelet transform has good noise reduction effects on three modulation methods of BPSK, QPSK, and 8PSK in AWGN channels. The applicable conditions of four soft and hard threshold methods, namely Stein unbiased likelihood adaptive threshold, fixed threshold, optimal predictive variable threshold, and maximum minimum criterion threshold, were compared and analyzed. In the Watterson channel model, a denoising method using wavelet transform first and then blind equalization was proposed, which verified that the denoising effect of this method is better than that of blind equalization.