In this letter, we study interleave frequency division multiplexing (IFDM) for multicarrier modulation in static multipath and mobile time-varying channels, which outperforms orthogonal frequency division multiplexing (OFDM), orthogonal time frequency space (OTFS), and affine frequency division multiplexing (AFDM) by considering practical advanced detectors. The fundamental principle underlying existing modulation techniques is to establish sparse equivalent channel matrices in order to facilitate the design of low-complexity detection algorithms for signal recovery, making a trade-off between performance and implementation complexity. In contrast, the proposed IFDM establishes an equivalent fully dense and right-unitarily invariant channel matrix with the goal of achieving channel capacity, ensuring that the signals undergo sufficient statistical channel fading. Meanwhile, a low-complexity and replica maximum a posteriori (MAP)-optimal cross-domain memory approximate message passing (CD-MAMP) detector is proposed for IFDM by exploiting the sparsity of the time-domain channel and the unitary invariance in interleave-frequency-domain channel. Numerical results show that IFDM with extremely low-complexity CD-MAMP outperforms OFDM, OTFS, and AFDM with state-of-the-art orthogonal approximate message passing detectors, particularly at low velocities.

翻译：本文研究了在静态多径和移动时变信道中用于多载波调制的交织频分复用（IFDM），通过采用实用的先进检测器，其性能优于正交频分复用（OFDM）、正交时频空（OTFS）和仿射频分复用（AFDM）。现有调制技术的基本原理是建立稀疏等效信道矩阵，以便设计低复杂度的信号恢复检测算法，从而在性能与实现复杂度之间做出权衡。相比之下，所提出的IFDM建立了一个等效的全密集且右酉不变的信道矩阵，旨在达到信道容量，确保信号经历充分的统计信道衰落。同时，针对IFDM，利用时域信道的稀疏性和交织频域信道的酉不变性，提出了一种低复杂度且具有复制最大后验（MAP）最优性的跨域记忆近似消息传递（CD-MAMP）检测器。数值结果表明，采用极低复杂度CD-MAMP的IFDM在性能上超越了使用最先进正交近似消息传递检测器的OFDM、OTFS和AFDM，尤其在低速场景下表现突出。