Abstract With the advantage of high flexibility, unmanned aerial vehicle (UAV) can be deployed in a high height to provide high probability of line-of-sight (LoS) transmission for the ground units. Thus, UAV can bring much gain for communication systems. In this paper, we consider that a set of UAVs are deployed in the air to work as relays to aid the ground device-to-device (D2D) pairs. For the reason that the communication resource on one relay is limited and the positions of the relays are different, network performance is significantly impacted by relay assignment. Considering that there is no central controller in this relay network, centralized relay assignment approaches cannot be used. Thus, we propose a novel decentralized relay selection approach based on relay exchange, aiming to maximize the total capacity of the network. With the proposed approach, the total capacity of the relay network is strictly non-decreasing with the increase of the iteration steps. Numerical results show that the proposed approach have attractive properties.

中文翻译：

---

分布式无人机辅助D2D网络基于交换的非递减中继选择

摘要无人机具有很高的灵活性，可以在高空部署，从而为地面单位提供很高的视距（LoS）传输可能性。因此，无人机可以为通信系统带来很多收益。在本文中，我们认为有一组无人机在空中部署以充当中继器，以辅助地面设备到设备（D2D）对。由于一个中继上的通信资源有限并且中继的位置不同的原因，中继分配会严重影响网络性能。考虑到该中继网络中没有中央控制器，因此无法使用集中式中继分配方法。因此，我们提出了一种基于中继交换的新型分散式中继选择方法，旨在最大化网络的总容量。使用所提出的方法，中继网络的总容量随着迭代步骤的增加而严格不减少。数值结果表明，该方法具有吸引人的特性。