Trajectory optimization method for the OFDM-UAV relay broadcast communication system
To improve the performance of the unmanned aerial vehicle(UAV)relay broadcast communication system,taking into consideration the entire communication links from the base station to the UAV and from the UAV to the users,the orthogonal frequency division multiplexing(OFDM)based trajectory optimization method is proposed for the UAV relay broadcast communication system with frequency selective fading channels.First,the OFDM-based UAV relay broadcast communication model is provided.Then,approximate calculation formula for the interruption probability for a single-user node and that for the system average interruption probability are theoretically derived.Furthermore,two trajectory methods for the relay UAV are proposed based on the optimization criteria of minimizing the average interruption probability and minimizing the maximum user interruption probability.The effectiveness and correctness of the proposed optimization method are demonstrated by computer simulations,which indicates that the OFDM-based UAV relay broadcasting communication system can effectively overcome frequency-selective fading,and achieve better connectivity under the decode-and-forward transmission mode than the amplify-and-forward mode in multipath channels.The interruption performance of the system,derived based on the criterion of minimizing average interruption probability,surpasses that obtained by minimizing the maximum user interruption probability criterion.
UAV relaybroadcast communicationorthogonal frequency division multiplexingtrajectory optimizationinterruption probability