This paper investigates the orthogonal time frequency space (OTFS) transmission for enabling ultra-reliable low-latency communications (URLLC). To guarantee excellent reliability performance, pragmatic precoder design is an effective and indispensable solution. However, the design requires accurate instantaneous channel state information at the transmitter (ICSIT) which is not always available in practice. Motivated by this, we adopt a deep learning (DL) approach to exploit implicit features from estimated historical delay-Doppler domain channels (DDCs) to directly predict the precoder to be adopted in the next time frame for minimizing the frame error rate (FER), that can further improve the system reliability without the acquisition of ICSIT. To this end, we first establish a predictive transmission protocol and formulate a general problem for the precoder design where a closed-form theoretical FER expression is derived serving as the objective function to characterize the system reliability. Then, we propose a DL-based predictive precoder design framework which exploits an unsupervised learning mechanism to improve the practicability of the proposed scheme. As a realization of the proposed framework, we design a DDCs-aware convolutional long short-term memory (CLSTM) network for the precoder design, where both the convolutional neural network and LSTM modules are adopted to facilitate the spatial-temporal feature extraction from the estimated historical DDCs to further enhance the precoder performance. Simulation results demonstrate that the proposed scheme facilitates a flexible reliability-latency tradeoff and achieves an excellent FER performance that approaches the lower bound obtained by a genie-aided benchmark requiring perfect ICSI at both the transmitter and receiver.
翻译:本文调查了用于极易恢复的低延迟通信(URLLC)的正方时频空间(OTFS)传输,以确保极易恢复的低延迟通信(URLLC)的精确可靠性能。为了确保可靠性,实用的预译器设计是一个有效和不可或缺的解决方案。然而,设计需要发报器(ICSIT)的准确即时频道状态信息,而在实践中并不总是有这种信息。为此,我们采取了一种深层次的学习(DL)方法,利用历史延迟估计多普勒域网(DDCs)的隐含性特征直接预测将在下一个时间框架内采用的预译码器,以最大限度地降低框架误差率(FER),这样可以进一步提高系统运行的可靠性。为了实现这一框架,我们首先建立一个预测性传输协议,为预译器设计一个总的问题,因为封闭式的理论FERT表达方式是系统可靠性的客观功能。 然后,我们提出一个基于DLL的预测前方位预码设计框架,利用一个不超度的Sredial Streader设计机制来进一步改进拟议计划的精确性能性能。 作为实现一个长期IMLDC-DDC-DestrevalS的系统,我们设计图图图图图图图图图图图图图。