Lampel Franz, Joudeh Hamdi, Alvarado Alex, Willems Frans M J
Information and Communication Theory Lab, Signal Processing Systems Group, Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
Entropy (Basel). 2022 Nov 22;24(12):1704. doi: 10.3390/e24121704.
In orthogonal time frequency space (OTFS) modulation, information-carrying symbols reside in the delay-Doppler (DD) domain. By operating in the DD domain, an appealing property for communication arises: time-frequency (TF) dispersive channels encountered in high-mobility environments become time-invariant. OTFS outperforms orthogonal frequency division multiplexing (OFDM) in high-mobility scenarios, making it an ideal waveform candidate for 6G. Generally, OTFS is considered a pre- and postprocessing step for OFDM. However, the so-called Zak transform provides the fundamental relation between the DD and time domain. In this work, we propose an OTFS system based on the discrete Zak transform (DZT). To this end, we discuss the DZT and establish the input-output relation for time-frequency (TF) dispersive channels solely by the properties of the DZT. The presented formulation simplifies the derivation and analysis of the input-output relation of the TF dispersive channel in the DD domain. Based on the presented formulation, we show that operating in the DD incurs no loss in capacity.
在正交时频空间（OTFS）调制中，携带信息的符号位于时延-多普勒（DD）域。通过在DD域中进行操作，通信产生了一个吸引人的特性：在高移动性环境中遇到的时频（TF）色散信道变得时不变。在高移动性场景中，OTFS优于正交频分复用（OFDM），使其成为6G的理想波形候选。一般来说，OTFS被认为是OFDM的预处理和后处理步骤。然而，所谓的Zak变换提供了DD域和时域之间的基本关系。在这项工作中，我们提出了一种基于离散Zak变换（DZT）的OTFS系统。为此，我们讨论了DZT，并仅通过DZT的特性建立了时频（TF）色散信道的输入-输出关系。所提出的公式简化了DD域中TF色散信道输入-输出关系的推导和分析。基于所提出的公式，我们表明在DD域中操作不会导致容量损失。
