Adaptive Channel Selection and Transmission Timing Control for Simultaneous Receiving and Sending in Relay-Based UAV Network

Recently, the demand for technology that can wirelessly transmit images taken by unmanned aerial vehicles (UAVs) has increased. Relay transmission technology is attracting particular attention, as it can provide wireless transmission to remote locations even in environments lacking infrastructure. Here, we focus on further developing an existing relay transmission system, namely, the simultaneous reception and transmission method, using multiple frequency bands. In this method, a relay node receives data from a source node and simultaneously transmits data to a destination node using another channel. This technology has the advantages of high frequency utilization efficiency and a short transmission time; however, buffer overflow at the relay node may remain, which could contribute to video quality degradation. Thus, we propose a buffer control method involving two proposed elements: a channel selection method, and a transmission start timing control method. By applying these two methods, we show that the buffer overflow rate at the relay node is decreased, and the amount of data that can be received by the destination node is maximized within the assigned sub frame. Ultimately, these results can contribute to improving the quality of videos transmitted in real-time using relay transmission with UAVs.