Short Packet Communications in UAV-NOMA System With Imperfect SIC

Recently, unmanned aerial vehicle (UAV)-assisted wireless communication systems gained a lot of attention due to the provision of highly probable line-of-sight communication links. However, reliable UAV communication with the base station is crucial for the control and non-payload communication (CNPC) to smoothly assist the application of UAVs. Specific to CNPC requiring less latency and high reliability, in this work, the performance of the UAV-non-orthogonal multiple access (NOMA) system is evaluated with imperfect successive interference cancellation (SIC) and short packet transmission. Further, the bounds on the fractional power required by each UAV of the NOMA pair are derived under imperfect SIC. In addition, we derive a pairing criterion required for each NOMA pair to achieve rates better than orthogonal multiple access (OMA) based rates. We propose a pairing algorithm and three different power allocation strategies that perform better than the state-of-the-art algorithms. Through Monte Carlo simulations, we show that the proposed user pairing approach performs closer to the optimal solution (obtained using scipy) and better than near-far, uniform channel gain pairing algorithms, and OMA baseline.