The invention concerns a digital radio (2) for pseudo-duplex radio communication, and a method of transmission time mediation for pseudo-duplex radio communication.
A digital radio (2) is in time division duplex communication with a second digital radio (4) over a single radio channel. Control of the radio channel may reside with either radio. However, authority for a radio to change the frame format in order to increase the proportion of time for which it transmits always resides entirely with the radio currently transmitting the least per frame. This is also the radio which transmits first in each frame. This arrangement lows rapid response to a need for a radio to move from listening to speaking mode, thereby reducing speech clipping.
When the digital radio (2) and the second digital radio (4) are transmitting for equal proportions of the frame, authority to change the frame format passes to the radio that is transmitting at that instant.
The apparatus and method of the invention provide a rapid switching of transmission mode, with minimal speech clipping when a user of the radio (2) starts to speak.