A packet control unit for a radio telecommunications system such as GPRS
has a radio link control/medium access control blocks scheduler which
allocates a number of temporary block flow queues to a timeslot for
transmission to a mobile system; a fixed allocation table is provided
having allocation slots corresponding to RAC blocks, and the RAC blocks
scheduler reads the table cyclically and allocates slots according to the
reading. Timeslots are requested later during increased demand conditions
and are released earlier during decreasing demand conditions than in
currently known arrangements.