摘要 |
In a UMTS system, the AICH is arranged to send, in addition to signals acknowledging that a preamble ( 164 ) from a mobile ( 12 ) is at an acceptable strength, further signals ( 171, 176 ) acknowledging message signals ( 168, 178 ) from the mobile. Preferably the further signal ( 171 ) is a negative acknowledgement signal, indicating that a message ( 168 ) is corrupted. Application of the invention avoids the involvement of layer ( 2 ) in message acknowledgement. |