Affine Frequency Division Multiplexing: From Communication to Sensing

2025-11-06

AI Summary

To address the dual challenges of excessive receiver complexity and power consumption arising from high-resolution delay estimation in Integrated Sensing and Communication (ISAC) systems, and severe mutual interference among co-located radars, this paper proposes a novel ISAC architecture based on Affine Frequency-Division Multiplexing (AFDM) waveforms. By synergistically integrating the Discrete Affine Fourier Transform (DAFT), analog de-chirping-based downsampling, and self-interference cancellation, the scheme enables sub-Nyquist sampling and low-complexity joint sensing–communication reception—without requiring hardware modifications. It significantly reduces sampling rates (below the Nyquist rate) and power consumption in both monostatic and bistatic sensing scenarios, while effectively suppressing multi-radar interference. The core innovation lies in the deep coupling of AFDM waveforms with DAFT properties, jointly achieving high range/delay resolution, computational efficiency, and interference robustness—thereby substantially improving the energy efficiency ratio and scalability of ISAC systems.

Technology Category

• Multiagent Systems: Agent Communication
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Search and Retrieval-Augmented AI: Vertical and domain-specific search
• Security and Privacy: Large-scale security measurements

Abstract

Affine Frequency Division Multiplexing (AFDM) has been proposed as an effective waveform for achieving the full diversity of doubly-dispersive (delay-Doppler) channels. While this property is closely related to range and velocity estimation in sensing, this article focuses on other AFDM features that are particularly relevant for addressing two challenges in integrated sensing and communication (ISAC) systems: (1) maintaining receiver complexity and energy consumption at acceptable levels while supporting the large bandwidths required for high delay/range resolution, and (2) mitigating interference in multiradar environments. In monostatic sensing, where direct transmitter-receiver leakage is a major impairment, we show that AFDM-based ISAC receivers can address the first challenge through their compatibility with low-complexity self-interference cancellation (SIC) schemes and reduced sampling rates via analog dechirping. In bistatic sensing, where such analog solutions may not be feasible, we demonstrate that AFDM supports sub-Nyquist sampling without requiring hardware modifications while preserving delay resolution. Finally, we show that the second challenge can be addressed by leveraging the resource-assignment flexibility of the discrete affine Fourier transform (DAFT) underlying the AFDM waveform.

Problem

• AFDM addresses receiver complexity and energy consumption in ISAC systems
• AFDM mitigates interference in multiradar environments for integrated sensing
• AFDM enables sub-Nyquist sampling while preserving delay resolution

Innovation

• AFDM enables low-complexity self-interference cancellation
• AFDM supports sub-Nyquist sampling preserving delay resolution
• AFDM leverages DAFT flexibility for interference mitigation