A mobile communications system includes a radio access network, such as an
Enhanced General Packet Radio Service (EGPRS) network, in which mobile
stations are able to enter into a discontinuous transmission (DTX) mode.
During DTX mode of a first mobile station that is allocated a channel
portion (e.g., a time slot of a frame), the radio access network is able
to multiplex traffic from another mobile station onto the same channel
portion. A mechanism is provided to enable the first mobile station to
send a request for re-allocation of the channel portion. The request
includes a real-time fast access associated control channel (RTFACCH)
resource request message (RTRRM). In response to the RTRRM, the radio
access network sends an RTFACCH resource assignment message (RTUAM). An
interleaving scheme is also provided for half-rate mobile stations, in
which one set of traffic frames are interleaved over plural bursts
according to a first algorithm and a second set of traffic frames are
interleaved over plural bursts according to a second algorithm.