The key to developing future generations of wireless communication systems lies in the expansion of extant methodologies, which ensures the coexistence of a variety of devices within a system. In this paper, we assume several multicasting (MC) groups comprising three types of heterogeneous users including Information Decoding (ID), Energy Harvesting (EH) and both ID and EH. We present a novel framework to investigate the multi-group (MG) - MC precoder designs for three different scenarios, namely, Separate Multicast and Energy Precoding Design (SMEP), Joint Multicast and Energy Precoding Design (JMEP), and Per-User Information and/or Energy Precoding Design (PIEP). In the considered system, a multi-antenna source transmits the relevant information and/or energy to the groups of corresponding receivers using more than one MC streams. The data processing users employ the conventional ID receiver architectures, the EH users make use of a non-linear EH module for energy acquisition, while the users capable of performing both ID and EH utilize the separated architecture with disparate ID and non-linear EH units. Our contribution is threefold. Firstly, we propose an optimization framework to i) minimize the total transmit power and ii) to maximize the sum harvested energy, the two key performance metrics of MG-MC systems. The proposed framework allows the analysis of the system under arbitrary given quality of service and harvested energy requirements. Secondly, to deal with the non-convexity of the formulated problems, we transform the original problems respectively into equivalent forms, which can be effectively solved by semi-definite relaxation (SDR) and alternating optimization. The convergence of the proposed algorithms is analytically guaranteed. Thirdly, a comparative study between the proposed schemes is conducted via extensive numerical results, wherein the benefits of adopting SMEP over JMEP and PIEP models are discussed.

中文翻译：

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具有异构用户的SWIPT系统中能量优化的多组组播预编码

发展下一代无线通信系统的关键在于现有方法的扩展，这确保了系统中各种设备的共存。在本文中，我们假设几个组播（MC）组包括三种类型的异构用户，包括信息解码（ID），能量收集（EH）以及ID和EH。我们提供了一个新颖的框架来研究针对三种不同场景的多组（MG）-MC预编码器设计，即，单独的多播和能量预编码设计（SMEP），联合多播和能量预编码设计（JMEP）和每用户信息和/或能量预编码设计（PIEP）。在所考虑的系统中，多天线源使用一个以上的MC流将相关信息和/或能量发送到相应的接收器组。数据处理用户采用常规的ID接收器体系结构，EH用户使用非线性EH模块进行能量获取，而能够执行ID和EH的用户则使用具有不同ID和非线性EH单元的分离体系结构。我们的贡献是三倍。首先，我们提出了一个优化框架，以使MG-MC系统的两个关键性能指标i）最小化总发射功率，ii）使所采集的能量总和最大化。所提出的框架允许在任意给定的服务质量和收集的能量需求下对系统进行分析。其次，为了解决所提问题的非凸性，我们将原始问题分别转换为等价形式，这可以通过半定松弛（SDR）和交替优化来有效解决。解析算法保证了所提出算法的收敛性。第三，通过广泛的数值结果对提议的方案进行了比较研究，其中讨论了采用SMEP优于JMEP和PIEP模型的好处。