Integrated communications and localization (ICAL) will play an important part in future sixth generation (6G) networks for the realization of Internet of Everything (IoE) to support both global communications and seamless localization. Massive multiple-input multiple-output (MIMO) low earth orbit (LEO) satellite systems have great potential in providing wide coverage with enhanced gains, and thus are strong candidates for realizing ubiquitous ICAL. In this paper, we develop a wideband massive MIMO LEO satellite system to simultaneously support wireless communications and localization operations in the downlink. In particular, we first characterize the signal propagation properties and derive a localization performance bound. Based on these analyses, we focus on the hybrid analog/digital precoding design to achieve high communication capability and localization precision. Numerical results demonstrate that the proposed ICAL scheme supports both the wireless communication and localization operations for typical system setups.

翻译：通信与定位一体化（ICAL）将在未来第六代（6G）网络中发挥重要作用，用于实现万物互联（IoE），以支持全球通信与无缝定位。大规模多输入多输出（MIMO）低轨（LEO）卫星系统在提供广覆盖与增强增益方面具有巨大潜力，因此是实现泛在ICAL的理想候选方案。本文开发了一种宽带大规模MIMO低轨卫星系统，以在下行链路同时支持无线通信与定位操作。具体而言，我们首先表征信号传播特性并推导定位性能界。基于这些分析，我们重点研究混合模数预编码设计，以实现高通信能力与定位精度。数值结果表明，所提出的ICAL方案能够在典型系统配置下同时支持无线通信与定位操作。