This work studies multigroup multicasting transmission in cloud radio access networks (C-RANs) with simultaneous wireless information and power transfer, where densely packed remote radio heads (RRHs) cooperatively provide information and energy services for information users (IUs) and energy users (EUs), respectively. To maximize the weighted sum rate (WSR) of information services while satisfying the energy harvesting levels at EUs, an optimization of joint beamforming design for the fronthaul and access links is formulated, which is however neither smooth nor convex and is indeed NP-hard. To tackle this difficulty, the smooth and successive convex approximations are used to transform the original problem into a sequence of convex problems, and two first-order algorithms are developed to find the initial feasible point and the nearly optimal solution, respectively. Moreover, an accelerated algorithm is designed to improve the convergence speed by exploiting both Nesterov and heavy-ball momentums. Numerical results demonstrate that the proposed first-order algorithms achieve almost the same WSR as that of traditional second-order approaches yet with much lower computational complexity, and the proposed scheme outperforms state-of-the-art competing schemes in terms of WSR.

中文翻译：

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具有 SWIPT 的超密集 C-RAN 中无线前传和接入链路的协作波束成形：一阶方法

这项工作研究了云无线电接入网络 (C-RAN) 中同时进行无线信息和电力传输的多组组播传输，其中密集封装的远程无线电头 (RRH) 合作为信息用户 (IU) 和能源用户 (EU) 提供信息和能源服务。 ）， 分别。为了在满足 EU 的能量收集水平的同时最大化信息服务的加权和率 (WSR)，制定了前传和接入链路的联合波束成形设计的优化，但它既不平滑也不凸，实际上是 NP-hard。为了解决这个困难，使用平滑和连续凸逼近将原始问题转换为一系列凸问题，并开发了两种一阶算法，分别用于寻找初始可行点和近似最优解。此外，加速算法旨在通过利用 Nesterov 和重球动量来提高收敛速度。数值结果表明，所提出的一阶算法实现了与传统二阶方法几乎相同的 WSR，但计算复杂度要低得多，并且所提出的方案在 WSR 方面优于最先进的竞争方案。