A Simplified Affine Frequency Division Multiplexing System for High Mobility Communications

Jinming Du, Yanqun Tang, Haoran Yin, Jiajun Zhu, Yu Zhou

Abstract: Analogous to orthogonal time frequency space (OTFS), affine frequency division multiplexing (AFDM) emerges as a promising solution for achieving ultra-reliable communication under time-varying channels with large Doppler shifts. To apply this new modulation technique for next-generation communications, there is an expectation that it will be easily integrated into current systems without major modifications. In this paper, we propose a low-complexity waveform called simplified-AFDM (S-AFDM), which is more compatible with existing techniques by reducing the parameter settings in AFDM. First, We provide a general framework and formulate the input-output relation of the S-AFDM system in the discrete affine Fourier transform (DAFT) domain. Furthermore, we present a detailed analysis of the diversity order of S-AFDM in single-input single-output (SISO) setting with maximum likelihood (ML) detection. Numerical results demonstrate that the proposed modulation scheme exhibits the same performance of classic AFDM with commonly used detectors, while halving its addtional modulation complexity superimposed on the orthogonal frequency division multiplexing,