Optimal Relay Positions in Cooperative UAV Relay Networks

The primary objective of this letter is to identify the optimal relay positions theoretically for one-way relay protocols. Account is taken of the signal propagation scenario typically experienced by the communication systems utilizing unmanned aerial vehicles (UAVs). This letter focuses on a relay network using UAVs, where it is necessary to consider the geometric network configuration including the relay location most suitable to the surrounding environment. This letter assumes the Decode-and-Forward (DF), Lossy Forward (LF), and Adaptive Decode-and-Forward (ADF) protocols in the one-way UAV relay network having Source, Destination, and Relay nodes, and derive theoretically their outage probabilities. Results of numerical calculations are presented to demonstrate the optimal positions in several propagation environments.