Low-Complexity AFDM Signal Detection for High-Mobility and LEO Satellite Communications

High-mobility and LEO satellite channels cause severe Doppler dispersion that degrades OFDM performance. Affine frequency division multiplexing (AFDM) mitigates this effect with an efficient chirp-based design. To further lower receiver complexity, this paper introduces a variational Bayesian (VB) detector using mean-field factorization and coordinate-ascent updates, eliminating matrix inversion. The proposed method achieves fast, low-complexity soft detection with superior BER for next-generation LEO systems.