Analytical study of intercarrier interference in chirp-based AFDM system

Abstract Affine Frequency Division Multiplexing (AFDM) has emerged as a robust modulation scheme capable of handling the challenges posed by doubly dispersive wireless channels. By utilizing chirp-based waveforms, AFDM offers inherent resilience against time and frequency dispersion, positioning it as a potential alternative to Orthogonal Frequency Division Multiplexing (OFDM), especially in high-mobility environments. However, like OFDM, AFDM is still susceptible to Intercarrier Interference (ICI), particularly in the presence of Carrier Frequency Offset (CFO). In this work, I derive analytical expressions for the ICI coefficients and the resulting Carrier-to-Interference Ratio (CIR) in AFDM. To understand the impact of ICI, I evaluate the Bit Error Rate (BER) performance of AFDM under both Additive White Gaussian Noise (AWGN) and Rayleigh fading channels. Simulations results compare the BER performance of AFDM with and without ICI, clearly highlighting the performance degradation due to ICI.