Performance evaluation of AFDM for integrated sensing and communications in doubly dispersive channels

Integrated Sensing and Communications (ISAC) has emerged as a key enabling technology for beyond-5G and 6G systems, particularly in high-mobility scenarios dominated by doubly dispersive wireless channels. This paper investigates the performance of Affine Frequency Division Multiplexing (AFDM), a recently proposed chirp-based modulation waveform, in the context of ISAC. AFDM maps information symbols into the affine delay-chirp domain, exhibiting inherent robustness against delay and Doppler spreads. To enhance detection performance, a Linear Minimum Mean Square Error (LMMSE) equalizer is employed at the receiver to mitigate the channel-induced distortions. We provide a comprehensive evaluation of AFDM by analyzing its Bit-Error Rate (BER) and throughput performance under varying Signal-to-Noise Ratio (SNR) levels, number of multipath scattered components, and channel estimation errors. Simulation results demonstrate that the proposed AFDM consistently outperforms conventional Orthogonal Frequency Division Multiplexing (OFDM). For example, at 20 dB SNR with 15 scattered paths and a channel estimation error of σ h = 0.1, the proposed AFDM achieves a BER of 4.97×10 −3 , compared to OFDM’s 1.43×10 −2 . In terms of throughput, the proposed AFDM maintains above 63.6 Mbps under the same conditions, whereas OFDM drops to 63.08 Mbps. These findings underscore AFDM’s suitability for ISAC applications, offering improved resilience, spectral efficiency, and compatibility with dynamic and high-frequency environments.