Joint Channel Estimation and Data Detection for AFDM With Superimposed Pilots

Affine frequency division multiplexing (AFDM) is a promising waveform for next generation wireless networks, effectively resisting the channel double selectivity. Conventional embedded pilot (EP) scheme for AFDM requires additional guard symbols, leading to a reduction in spectral efficiency (SE). To address this issue, superimposed pilot (SP)-based schemes have been proposed, improving the SE; however, at the cost of increased computational complexity at the receiver. In this work, we propose an iterative joint channel estimation and data detection scheme for AFDM by harnessing SPs, aiming to enhance the SE while reducing the detection complexity. Simulation results demonstrate that our proposed scheme outperforms the conventional SP-based scheme in both channel estimation and data detection, while achieving a lower computational complexity. Notably, under low data power conditions, our approach surpasses the EP scheme in terms of both SE and data detection accuracy.