Performance Analysis of Multitier Terrestrial-LEO-GEO Communication Systems. - Gaofeng Pan; Yi Tao; Yuanyuan Ma; Shuai Wang 013; Changhao Du; Rui Zhang 023; Zizheng Hua; Junjie Zhao; Chuntao Kang; Zhongguo Fan; Gangtao Han; Dusit Niyato (IEEE Internet Things J., 2026)