A transmitter produces radio signal bursts in periodic time slots allocated to
a time-division multiplexed channel. The radio signal of each burst is made up
of digital symbols comprising two training sequences enabling the receiver to estimate
demodulation parameters and information symbols which the receiver can estimate
by a demodulation applied using the estimated parameters. The two training sequences
are placed at the start and the end of the burst so that the receiver uses them
to demodulate the received signal in the order of the symbols and demodulate the
received signal again in the reverse order of the symbols.
