Patent ID: 8315634

Claim:
A method of rerouting calls between a plurality of core network nodes in a telecommunication system provided with radio access nodes, the plurality of core network nodes being configured to serve a pool area within which a mobile station may roam without a need to change a serving core network node, the pool area being served by the plurality of core network nodes in parallel, the method comprising: the mobile station, at an initiative of its user, transmitting a call set-up request; a radio access node capturing the call set-up request the serving core network node checking terrestrial transmission resources from it to the radio access node to determine if there are any free terrestrial resources which can be seized for the requested call; the radio access node, before forwarding the call set-up request, checking if there exist any free terrestrial resources from it to a current serving core network node; the radio access node, in case there are free terrestrial resources from it to the serving core network node, forwarding the call set-up request to the current serving core network node; the radio access node, in case there are no free terrestrial resources from it to the current serving core network node, selecting another core network node of the pool area and rerouting the call set-up request to the another core network node; and the radio access node, after rerouting the call set-up request to the another core network node, selecting a new serving core network node of the pool area in response to a location update message from the mobile station, wherein there are free terrestrial resources from the radio access node to the current serving core network node, wherein there are free terrestrial resources from the radio access node to the new serving core network node, and wherein the location update message comprises a permanent identity of the mobile station.