In the envisioned beyond-fifth-generation (B5G) and sixth-generation (6G) scenarios which expect massive multiple-input multiple-output (mMIMO) and high frequency communications in the millimeter-wave (mmWave) and Terahertz (THz) bands, efficiency in both energy and spectrum is of increasing significance. To that extent, a novel ISAC framework called "sparse codesigned communication and radar (SCCR)" systems is described, which codesigns both communication and radar signals by a sparsification of the resource domain and the waveform spectrum domain. This improves the spectral and energy efficiency, but at the inherent cost of missing radar spectrum and irregular beampattern, and decreased throughput and diversity. Such challenges can however be corroborated, by leveraging various sparsity-robust signal processing techniques such as sparse radar reconstruction and index modulation (IM). In light of the above, the white paper aims to outlined the proposed article which provide an overview and a novel classification of the relevant state-of-the-art (SotA) methods and the implications of the challenges in the sparse codesign of the system, followed by a variety of novel SCCR frameworks.

翻译：在预期实现大规模多输入多输出（mMIMO）以及毫米波（mmWave）和太赫兹（THz）频段高频通信的超越第五代（B5G）与第六代（6G）场景中，能量与频谱效率的重要性日益凸显。为此，本文提出一种名为“稀疏协同通信与雷达（SCCR）”的新型ISAC框架，该框架通过资源域与波形频谱域的稀疏化实现通信与雷达信号的协同设计。这提升了频谱与能量效率，但固有代价包括雷达频谱缺失、波束方向图不规则以及吞吐量与分集性能下降。然而，可借助稀疏雷达重构、索引调制（IM）等鲁棒稀疏信号处理技术应对此类挑战。基于此，本文旨在概述所提出的方案，系统梳理相关领域最新技术（SotA）的分类及其对系统稀疏协同设计挑战的启示，并介绍多种新型SCCR框架。