摘要 |
The infrastructure has a core network, radio network controllers linked to the core network and base stations provided with radio interfaces and each linked to one of the controllers. Ciphered information is transmitted over a first communication path in circuit mode between the core network and the terminal, passing through a first master controller, then over a second communication path in circuit mode between the core network and the terminal, passing through a second master controller. The second path is established in a transfer procedure comprising the transmission of adjustment data from the first to the second master controller and the suppression of the first path. These data are representative of a current value of a sequence number used to encipher the information and incremented at regular intervals, and of an offset between this sequence number and a time reference available to the second controller. |