South China University of Technology;
Guangzhou 510000;
China;
Dalian University of Technology;
Dalian 116000;
China;
University of York;
York YO105DD;
U.K;
University College London;
London WC1E 6BT;
U.K;
emergency communications; non-orthogonal multiple access(NOMA); Internet of Things(IoT); trajectory optimization; unmanned aerial vehicle(UAV);