A method is provided for transmitting a message comprising one or more preambles and a message body from a user equipment device to a network entity. The method includes determining whether it is allowed to transmit a first preamble of the message to the network entity in an immediately available time slot of a random access channel, transmitting the first preamble if it is allowed, and transmitting the message body if a positive acknowledgement to the preamble is received from the network entity on another channel. The user equipment device may determine transmitting the preamble invariably, based on a persistence value or an indication received from the network entity, based on whether the device has not transmitted on the random access channel for longer than a predetermined, or based on whether the device has not transmitted on the random access channel for longer than a random time period.