Some digital voice protocols are time slotted (TDMA), i.e. the transmitter of a station is not on all the time, and multiple stations may transmit digital voice on the same frequency at the same time by transmitting small digital bursts, one by one.
For example, DMR (MotoTRBO), which is already somewhat popular in amateur radio circles, has a duty cycle of slightly less than 50%, and two voice transmissions can be retransmitted by the same repeater at the same time.
Would it be possible to make a digital "simplex" voice repeater which would listen on one time slot and immediately repeat the received voice frame on the next time slot, on the same frequency? Do such repeaters exist for some protocol?
It'd work fine with a single antenna, and wouldn't require duplex filters. Much easier to set up than traditional voice repeaters.