Integrated sensing and communications (ISAC) is regarded as a key technology in next-generation (6G) mobile communication systems. Affine frequency division multiplexing (AFDM) is a recently proposed waveform that achieves optimal diversity gain in high mobility scenarios and has appealing properties in high-frequency communication. In this letter, we present an AFDM-based ISAC system. We first show that in order to identify all delay and Doppler components associated with the propagation medium, either the full AFDM signal or only its pilot part consisting of one discrete affine Fourier transform (DAFT) domain symbol and its guard interval can be used. Our results show that using one pilot symbol achieves almost the same sensing performance as using the entire AFDM frame. Furthermore, due to the chirp nature of AFDM, sensing with one pilot provides a unique feature allowing for simple self-interference cancellation, thus avoiding the need for expensive full duplex methods.

翻译：通感一体化（ISAC）被视为下一代（6G）移动通信系统的关键技术。仿射频分复用（AFDM）是近期提出的一种波形，能在高移动性场景中实现最优分集增益，并在高频通信中展现出优良特性。本文提出一种基于AFDM的通感一体化系统。我们首先证明：为识别传播媒介相关的全部时延与多普勒分量，可采用完整AFDM信号，或仅采用由单个离散仿射傅里叶变换（DAFT）域符号及其保护间隔构成的导频部分。结果表明，使用单个导频符号可达到与使用整个AFDM帧几乎相同的感知性能。此外，由于AFDM的啁啾特性，基于单导频的感知可提供独特优势，能够实现简单的自干扰消除，从而避免采用昂贵的全双工方案。