Extremely large-scale array (XL-array) has emerged as a promising technology to enhance the spectrum efficiency and spatial resolution in future wireless networks, leading to a fundamental paradigm shift from conventional far-field communications towards the new near-field communications. Different from the existing works that mostly considered simultaneous wireless information and power transfer (SWIPT) in the far field, we consider in this paper a new and practical scenario, called mixed near- and far-field SWIPT, in which energy harvesting (EH) and information decoding (ID) receivers are located in the near- and far-field regions of the XL-array base station (BS), respectively. Specifically, we formulate an optimization problem to maximize the weighted sum-power harvested at all EH receivers by jointly designing the BS beam scheduling and power allocation, under the constraints on the ID sum-rate and BS transmit power. To solve this nonconvex optimization problem, an efficient algorithm is proposed to obtain a suboptimal solution by leveraging the binary variable elimination and successive convex approximation methods. Numerical results demonstrate that our proposed joint design achieves substantial performance gain over other benchmark schemes.

翻译：超大规模阵列（XL-array）已成为未来无线网络中提升频谱效率与空间分辨率的潜在关键技术，引发从传统远场通信向新型近场通信的根本性范式转变。与现有工作主要考虑远场场景下的无线携能通信（SWIPT）不同，本文研究一种新颖且实际的应用场景——混合近远场SWIPT，其中能量采集（EH）接收机与信息解码（ID）接收机分别位于XL-array基站（BS）的近场与远场区域。具体而言，本文通过联合设计基站波束调度与功率分配，在满足ID和速率与基站发射功率约束的条件下，构建一个最大化所有EH接收机加权和功率的优化问题。为求解该非凸优化问题，提出一种基于二元变量消除与逐次凸逼近方法的高效算法以获得次优解。数值结果表明，所提出的联合设计方案相较于其他基准方案能实现显著的性能增益。