Non-fluctuation interference rejection using an adaptive filter based on spectrum envelope analysis

Objectives . The rapid advancement of wireless technologies, including IoT and 5G/6G, is accompanied by an increase in the overall level of electromagnetic interference. This sets engineers the task of developing effective methods to suppress such interference, including especially challenging non-fluctuating interference of various kinds. The study aims to implement and analyze the effectiveness of a non-fluctuation interference rejection method using an adaptive filter based on spectrum envelope analysis. Methods . Mathematical modeling, spectral analysis, and adaptive filtering methods are used in the work. The described approach is based on spectrum envelope extraction for identification and subsequent suppression of nonfluctuation interference. Results . The effectiveness of an adaptive algorithm for suppressing non-fluctuation interference based on the analysis of the spectrum envelope has been demonstrate. This algorithm can be used as a means for isolating the envelope of the interference spectrum to enable the formation of the amplitude-frequency response of the notch filter in real time. Processing methods for three types of non-fluctuation interference were implemented and tested: harmonic, frequency-shift keying (FSK), and phase-shift keying (PSK). A signal with quadrature amplitude modulation forms a useful signal for the purposes of the study. The experimental results demonstrate the good efficiency of the proposed method. The developed adaptive notch filter based on spectrum envelope analysis is highly effective in combating harmonic interference to achieve energy gains of 8–9 dB depending on the relative intensity of interference. Notably, even as interference intensifies, the filter effectiveness persists, albeit with a slight reduction. The algorithm functions effectively under exposure to narrowband FSK and PSK interference. Conclusions . The proposed adaptive algorithm for suppressing fluctuation interference based on spectrum envelope analysis is optimally effective in the presence of harmonic interference within the communication channel, but less effective in the presence of more broadband interference. The study is of practical importance for digital communication systems, where high noise immunity is required in a complex electromagnetic environment.