full-duplex transmission of data in two directions simultaneously in the same channel. SMS is a done via Beidou-1 satellites, and Beidou-1 don't serve as positi

full-duplex transmission of data in two directions simultaneously in the same channel. SMS is a done via Beidou-1 satellites, and Beidou-1 don't serve as positioning at all today. Beidou-2 is just like GPS, positioning service only, no SMS or shit.