标题： 使用Zak-OTFS在具有移动性和时延扩展的信道中的差分通信 显示英文标题

标题： Differential Communication in Channels with Mobility and Delay Spread using Zak-OTFS

摘要： 基于Zak变换的正交时频空间（Zak-OTFS）是一种在延迟多普勒（DD）域中进行信号处理的调制方案。 在DD域中观察到的信道是可预测的。 然而，即使使用Zak-OTFS，仍需要周期性地发送导频信号，尽管速率较低。 在本文中，我们提出了一种针对Zak-OTFS系统的差分通信方案，以减轻对周期性导频传输的需求。 为此，我们分析表明，检测到的数据可以作为导频使用，并且从检测到的数据中获得的信道估计可以用于进一步的检测，从而实现通信的“差分”特性。 具体而言，我们利用Zak-OTFS中DD信道的预测能力，使用前一时刻的信道估计（从被当作导频的检测到的数据符号中获得）来检测下一时刻的数据，并向前传播。 其优势有两个。 首先，它允许数据符号享受更高的能量，因为原本用于导频符号的能量也可以分配给数据符号。 其次，与点导频或嵌入式导频相比，它实现了全频谱效率。 与实现全频谱效率的扩展导频方案相比，所提出的方法在较低复杂度下实现了更好的比特误码率。 显示英文摘要

摘要： Zak-transform based orthogonal time frequency space (Zak-OTFS) is a delay-Doppler (DD) domain modulation scheme in which the signal processing is carried out in the DD domain. The channel when viewed in the DD domain is predictable. However, even with Zak-OTFS, pilots need to be sent periodically, albeit at a lower rate. In this paper, we propose a differential communication scheme for Zak-OTFS systems that alleviates the need for periodic pilot transmission. Towards this, we analytically show that the detected data can be used as a pilot and that the channel estimate obtained from the detected data can enable further detection enabling the "differential" aspect of the communication. Specifically, we leverage the prediction capability of the DD channel in Zak-OTFS to use the channel estimate (obtained from detected data symbols treated as pilots) in the previous instant to detect data in the next instant and propagate this forward. The advantages are two fold. First, it allows the data symbols to enjoy higher energy since the energy that would otherwise be required for pilot symbols can also be allocated to data symbols. Second, it allows for full spectral efficiency compared to point or embedded pilots. Comparison with the full spectral efficiency achieving spread pilot scheme shows that the proposed method achieves better bit-error rate at lower complexity.