AI 中文总结
研究城市区域下行链路多小区MIMO系统中提高小区边缘UE容量问题，核心方法是将FD模式的HAPS与地面网络集成，通过SCA和AO算法设计波束，主要贡献是显著提升了小区边缘UE的容量。
AI 中文摘要
我们考虑一个城市区域的下行链路多小区多输入多输出（MIMO）系统，重点是提高小区边缘用户设备（UE）的容量。由于阴影、路径损耗和小区间干扰（ICI），这些UE的速率通常低于靠近基站的UE。为解决此问题，我们将高空气球平台站（HAPS）与地面网络集成作为边缘UE传输的中继。假设HAPS工作在全双工（FD）模式，利用其大尺寸通过分离收发天线增强无源自干扰（SI）抑制。在所提方案中，每个地面基站（BS）将边缘UE数据转发给FD-HAPS，再由其中继到目标边缘UE。为在BS和HAPS处设计波束，我们在总发射功率和最小服务质量（QoS）约束下制定和速率最大化问题。为解决该非凸问题，我们基于逐次凸逼近（SCA）和交替优化（AO）开发集中式算法以实现快速收敛。仿真结果表明，与仅地面网络相比，通过FD-HAPS中继信息显著提高了小区边缘UE的容量。
英文摘要
We consider a downlink multicell multiple-input multiple-output (MIMO) system in an urban region, with a focus on improving the capacity of cell-edge user equipments (UEs). These UEs typically experience lower rates than near UEs because of shadowing, path loss, and inter-cell interference (ICI). To address this issue, we integrate a high-altitude platform station (HAPS) with the terrestrial network as a relay for edge-UE transmissions. We assume that the HAPS operates in full-duplex (FD) mode and exploits its large physical size to enhance passive self-interference (SI) suppression by separating its transmit and receive antennas. In the proposed scheme, each terrestrial base station (BS) forwards edge-UE data to the FD-HAPS, which then relays the data to the intended edge UEs. To design beams at both BSs and HAPS, we formulate a sum-rate maximization problem for under total transmit-power and minimum quality-of-service (QoS) constraints. To solve the resulting non-convex problem, we develop a centralized algorithm based on successive convex approximation (SCA) and alternating optimization (AO) for fast convergence. Simulation results show that relaying information via FD-HAPS significantly improves the capacity of cell-edge UEs compared with a terrestrial-only network.
Comments9 pages, 3 figures, submitted for possible publication
