In this paper, we propose a cell-free scheme for unmanned aerial vehicle (UAV) base stations (BSs) to manage the severe intercell interference between terrestrial users and UAV-BSs of neighboring cells. Since the cell-free scheme requires enormous bandwidth for backhauling, we propose to use the sub-terahertz (sub-THz) band for the backhaul links between UAV-BSs and central processing unit (CPU). Also, because the sub-THz band requires a reliable line-of-sight link, we propose to use a high altitude platform station (HAPS) as a CPU. At the first time-slot of the proposed scheme, users send their messages to UAVs at the sub-6 GHz band. The UAVs then apply match-filtering and power allocation. At the second time-slot, at each UAV, orthogonal resource blocks are allocated for each user at the sub-THz band, and the signals are sent to the HAPS after analog beamforming. In the HAPS receiver, after analog beamforming, the message of each user is decoded. We formulate an optimization problem that maximizes the minimum signal-to-interference-plus-noise ratio of users by finding the optimum allocated power as well as the optimum locations of UAVs. Simulation results demonstrate the superiority of the proposed scheme compared with aerial cellular and terrestrial cell-free baseline schemes.
翻译:在本文中,我们提议为无人驾驶航空器(UAV)基地站制定无细胞计划,以管理地面用户和邻近细胞的UAV-BS之间的严重跨细胞干扰。由于无细胞计划需要巨大的回航带宽,我们提议使用亚梯字带用于UAV-BS和中央处理单位之间的回航连接。此外,由于分HZ波段需要一个可靠的直线链接,我们提议使用高空平台站作为CPU。在拟议办法的第一个时间段,用户在子6GHZ波段向UAVs发送信息。由于无细胞计划需要巨大的回航带宽度,我们提议使用子梯字带(Sub-Thz)带用于UAV-BS和中央处理单位之间的回程连接。此外,由于次频带需要有一个可靠的直线链接,因此我们提议使用高空平台站站站作为CPS。在模拟接收器接收器接收器中,在进行模拟的模拟比对准比平流率定位时,每个用户的最小的惯度定位定位定位定位定位将显示最佳的图像定位定位定位定位,每个用户的最优度定位定位定位为最佳定位定位定位定位定位定位定位。