Supporting high mobility is an important feature of the 6G mobile communication systems, which puts forward a great challenge for conventional orthogonal frequency division multiplexing (OFDM) systems due to the severe Doppler effects. Recently, orthogonal time frequency space (OTFS) has been proposed as a promising waveform for high-mobility scenarios, due to its excellent capability of exploiting delay-Doppler (DD) diversity to significantly improve the system performance. However, in multicell OTFS systems, intercell interference (ICI) is one of the major challenges, especially for cell-edge users (CEUs). In this article, the impacts of different types of interference on OTFS systems are first studied. Then, interference coordination and cooperative communications-based multicell OTFS systems are studied to overcome ICI, respectively. Next, simulation results are presented for the performance evaluation of these schemes. Finally, the main challenges are discussed and future research directions for multicell OTFS systems are highlighted. The performance evaluations demonstrate the effectiveness of interference coordination and cooperative communications on multicell OTFS systems.

中文翻译：

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迈向 6G 多小区正交时频空间系统：干扰协调与协作通信

支持高移动性是6G移动通信系统的重要特征，由于严重的多普勒效应，这对传统的正交频分复用（OFDM）系统提出了巨大的挑战。最近，正交时频空间（OTFS）由于其利用延迟多普勒（DD）分集来显着提高系统性能的出色能力，被认为是高移动性场景的一种有前途的波形。然而，在多小区 OTFS 系统中，小区间干扰 (ICI) 是主要挑战之一，特别是对于小区边缘用户 (CEU) 而言。本文首先研究了不同类型的干扰对 OTFS 系统的影响。然后，分别研究了基于干扰协调和协作通信的多小区OTFS系统来克服ICI。接下来，给出了这些方案的性能评估的仿真结果。最后，讨论了主要挑战并强调了多小区 OTFS 系统的未来研究方向。性能评估证明了多小区 OTFS 系统上干扰协调和协作通信的有效性。