We propose a channel estimation scheme based on joint sparsity pattern
learning (JSPL) for massive multi-input multi-output (MIMO) orthogonal
time-frequency-space (OTFS) modulation aided systems. By exploiting the
potential joint sparsity of the delay-Doppler-angle (DDA) domain channel, the
channel estimation problem is transformed into a sparse recovery problem. To
solve it, we first apply the spike and slab prior model to iteratively estimate
the support set of the channel matrix, and a higher-accuracy parameter update
rule relying on the identified support set is introduced into the iteration.
Then the specific values of the channel elements corresponding to the support
set are estimated by the orthogonal matching pursuit (OMP) method. Both our
simulation results and analysis demonstrate that the proposed JSPL channel
estimation scheme achieves an improved performance over the representative
state-of-the-art baseline schemes, despite its reduced pilot overhead.

提出了一种基于联合稀疏模式学习（JSPL）的信道估计方案，适用于大规模多输入多输出（MIMO）正交时频空（OTFS）调制辅助系统。通过利用延迟 - 多普勒 - 角（DDA）领域信道的潜在联合稀疏性，将信道估计问题转化为稀疏恢复问题，并采用脉冲和板条先验模型迭代估计信道矩阵的支撑集，同时引入了一个依赖于已识别支撑集的更高精度参数更新规则。然后，通过正交匹配追踪（OMP）方法估计支撑集对应的信道元素的具体值。无论减少的导频开销，我们的模拟结果和分析均表明，所提出的 JSPL 信道估计方案在性能上优于代表性的现有基准方案。

基于联合稀疏模式学习的大规模 MIMO-OTFS 系统信道估计

Joint Sparsity Pattern Learning Based Channel Estimation for Massive  MIMO-OTFS Systems

This paper introduces a new two-dimensional modulation technique called
Orthogonal Time Frequency Space (OTFS) modulation. OTFS has the novel and
important feature of being designed in the delay-Doppler domain. When coupled
with a suitable equalizer, OTFS modulation is able to exploit the full channel
diversity over both time and frequency. Moreover, it converts the fading,
time-varying wireless channel experienced by modulated signals such as OFDM
into a time-independent channel with a complex channel gain that is essentially
constant for all symbols.
This design obviates the need for transmitter adaptation, and greatly
simplifies system operation. The paper describes the basic operating principles
of OTFS as well as a possible implementation as an overlay to current or
anticipated standardized systems. OTFS is shown to provide significant
performance improvement in systems with high Doppler, short packets, and/or
large antenna array. In particular, simulation results indicate at least
several dB of block error rate performance improvement for OTFS over OFDM in
all of these settings.

该文介绍了一种新的二维调制技术，称为正交时频空调制。该技术在时延 - 多普勒域中设计，能够利用时间和频率的全部通道多样性，并将 OFDM 等调制信号经历的衰落、时变无线信道转换为具有基本恒定复杂信道增益的时间独立信道，从而消除了发射机适应性的需求，并大大简化了系统运行。模拟结果表明，在高多普勒、短数据包和 / 或大阵列系统中，OTFS 相对于 OFDM 可以至少提供几个分贝的误码率性能改进。