Abstract: Controlling access by a User Equipment (UE) to a cellular network may be effected by: receiving an instruction at the UE from a base station of the cellular network regarding transmission by the UE over a Random Access Channel (RACH) of the cellular network; and controlling when transmissions are made from the UE over the RACH, on the basis of the received instruction. In some cases, a transmission over the RACH may be made in response to the received instruction, which gives permission for the UE to transmit if it has data to send. In other cases, the instruction specifies a Group Identifier, which is compared with a Group Identifier specific to the UE and transmission over the RACH may be avoided based on the comparison. In particular, the UE may be a Machine Type Communication device.