论文标题
使用可重构的智能表面改善无细胞MIMO中的无人机通信
Improving UAV Communication in Cell Free MIMO Using a Reconfigurable Intelligent Surface
论文作者
论文摘要
当前陆地网络中无人驾驶汽车（UAV）的通信遭受信号强度较差，因为访问点的倾斜（AP）被优化，可为地面用户目的（GUES）提供优化。为了解决这个问题，可以向上倾斜AP天线，或者分配更多的功率来服务无人机。但是，这对GUE下行链路（DL）率产生负面影响。在本文中，我们建议使用可重新配置的智能表面（RIS）来解决这一挑战，以增强无人机通信，同时保留3GPP向下规定的天线倾斜，并有可能改善GUE的DL性能。我们表明，在APS的GUES和UAV之间分配的共轭光束成形（CB）预编码和适当的功率，具有配置的相移的RI，将无线电信号朝着无人机反射到无人机，可以显着改善无人机DL吞吐量，同时使GUES受益。提出的数值结果表明，RIS-ADERD系统可以以所需的数据速率为无人机提供无人机，同时改善与CF-MIMO系统相对于没有无人机和RIS的GUES DL性能。我们通过在反映元素，无人机高和功率拆分因子的RI数量下进行的模拟来支持这一结论。
Communication with unmanned aerial vehicles (UAVs) in current terrestrial networks suffers from poor signal strength due to the down-tilt of the access points (APs) that are optimized to serve ground users ends (GUEs). To solve this, one could tilt the AP antenna upwards or allocate more power to serve the UAV. However, this negatively affects GUE downlink (DL) rates. In this paper, we propose to solve this challenge using a reconfigurable intelligent surface (RIS) to enhance the UAV communication while preserving the 3GPP- prescribed downwards antenna tilt and potentially improving the DL performance of the GUE. We show that under conjugate beamforming (CB) precoding and proper power split between GUEs and the UAV at the APs, an RIS with phase-shifts configured to reflect radio signals towards the UAV can significantly improve the UAV DL throughput while simultaneously benefiting the GUEs. The presented numerical results show that the RIS- aided system can serve a UAV with a required data rate while improving the GUEs DL performance relative to that in a CF- MIMO system without a UAV and an RIS. We support this conclusion through simulations under a varying numbers of RIS reflecting elements, UAV heights, and power split factor.
