Owing to the rapid and facile deployment of unmanned aerial vehicles (UAVs), the third-generation partnership programme has recently shown considerable interest in UAVs for assisting current terrestrial base stations. Hence, the feasibility of using UAVs has been vigorously investigated for enhancing the performance of traditional ground-based communications, e.g. coverage and quality-of-service enhancement under natural disaster or overwhelming data requirement conditions. Here, however, the energy-efficient operation of the UAV is necessary to obtain the essential benefits. To strengthen the base of operation and management of UAVs in cellular systems, the authors consider in this Letter a single mission in which a small-size UAV transmits a given data volume to a cell boundary user. They design the transmit power and altitude of the UAV to complete the mission with high-energy efficiency. From the numerical results, it is verified that the UAV transmitting data with the designed transmit power at the designed altitude can complete the mission with near-optimal, i.e. maximum, energy efficiency.

中文翻译：

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小型无人机节能完成任务的传输功率和高度设计

由于无人机 (UAV) 的快速和轻松部署，第三代合作伙伴计划最近对无人机辅助当前地面基站表现出相当大的兴趣。因此，使用无人机来提高传统地面通信性能的可行性已经得到了大力研究，例如在自然灾害或压倒性数据需求条件下的覆盖和服务质量增强。然而，在这里，无人机的节能运行是获得基本好处的必要条件。为了加强蜂窝系统中无人机​​的操作和管理基础，作者在这封信中考虑了一个单一的任务，其中小型无人机向小区边界用户传输给定的数据量。他们设计了无人机的发射功率和高度，以高能效完成任务。从数值结果验证了在设计高度以设计发射功率发射数据的无人机可以以接近最优的，即最大的能量效率完成任务。