Digital radio

摘要

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 ). The digital radio ( 2 ) derives a source signal activity parameter (VAD) indicating the likelihood of there being a source signal for transmission by the digital radio ( 2 ) to the second digital radio ( 4 ) over a single radio channel. The digital radio ( 2 ) also derives a first value (VADDir₁) of a signal direction parameter (VADDir) in dependence on both the value of the signal activity parameter (VAD) for the digital radio ( 2 ) and a second value (VADDir₂) of the signal direction parameter (VADDir) received from the second digital radio ( 4 ); The digital radio ( 2 ) selects the proportions of time for transmission and reception over the single radio channel in dependence on the first value (VADDir₁) of the signal direction parameter (VADDir). The digital radio ( 2 ) also transmits the first value (VADDir₁) of the signal direction parameter (VADDir) to the second digital radio ( 4 ), to allow the second digital radio ( 4 ) to perform an analogous update of its value of the signal direction parameter (VADDir). The apparatus and method of the invention are robust to radio channel and VAD value imperfections.