Patent ID: 8249017

Claim:
A cellular communication system comprising: a core network, a first radio access network coupled to the core network, the first radio access network being a packet switched network; a second radio access network coupled to the core network, the second radio access network being a packet switched and circuit switched radio access network; a user equipment capable of supporting air interface communications of both the first radio access network and the second radio access network; a mobility management entity for managing user equipment mobility in the first radio access network; and a circuit switch mobile switching centre arranged to support circuit switched communications of the second radio access network; and wherein the user equipment comprises: a detecting unit for detecting an initiation of a circuit switched application supported by a circuit switched communication service, and a reselection unit for initiating an access network reselection process from the first radio access network to the second radio access network in response to the detection, the reselection unit being arranged to transmit a location update message to the circuit switch mobile switching centre; the circuit switch mobile switching centre comprises a notifying unit for notifying the mobility management entity of the initiation of the access network reselection process in response to receiving the location update message; and the mobility management entity comprises a routing change unit for initiating a routing association change for a routing association of the user equipment from being an association with the first radio access network to being an association with the second radio access network in response to the notification.