Exchange-Based Non-Decreasing Relay Selection For Decentralized UAVs-aided D2D Networks

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.