Granting access to a communication channel for several user devices by a base station includes receiving, from at least a first and second user device, at least a first request to access the communication channel and a second request to access the communication channel (1202), the first request including a first random access preamble and a first payload, and the second request including a second random access preamble and a second payload, and transmitting, to at least the first and second user devices, a response message including at least a first control channel resource assignment configuring at least a first control channel resource for the at least the first user device to transmit an acknowledgement of the response message (1208).