| 摘要 |
A communications device is configured to transmit data to a mobile communications network. The mobile communications network includes one or more network elements providing a wireless access interface for communicating with the communications device. The communications device comprises a transmitter configured to transmit signals to the mobile communications network via the wireless access interface provided by the one or more network elements of the mobile communications network, and a receiver configured to receive signals from the mobile communications network via the wireless access interface provided by the one or more network elements of the mobile communications network, and a controller configured to control the transmitter to transmit a random access message to a first network element via a random access channel of the wireless access interface which is common to one or more other communications devices, to receive an acknowledgement in response to the random access message providing an indication of an allocation of the communications resources of the shared up-link channel for the communications device to transmit signals to the mobile communications network or a negative acknowledgment providing an indication that the communications device has not been allocated communications resources of the shared up-link channel, wherein in response to detection of one or more random access failure conditions by the controller, the controller is configured in combination with the transmitter to re-transmit the random access message one or more times, each re-transmission of the random access message being after a variable delay which is greater than or equal to the delay of a previous re-transmission for each re-transmission. Accordingly by re-transmitting a random access message after detection of a random access failure condition such as might occur if the network element is not able to cope with a volume of random access messages, then by increasing the delay between re-transmissions of the random access messages, there is a greater likelihood that the congestion will clear enough for a response to be transmitted to the network element. |
