US 9,813,949 B2
Technique for terminating call set up in a CSFB situation
Ralf Keller, Würselen (DE); Fredrik Lindholm, Stockholm (SE); and Karl-Peter Ranke, Herzogenrath (DE)
Assigned to Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
Filed by Telefonaktiebolaget L M Ericsson (publ), Stockholm (SE)
Filed on May 9, 2014, as Appl. No. 14/274,208.
Application 14/274,208 is a continuation of application No. PCT/EP2014/059482, filed on May 8, 2014.
Prior Publication US 2015/0327124 A1, Nov. 12, 2015
Int. Cl. H04W 36/00 (2009.01); H04L 29/06 (2006.01); H04W 88/00 (2009.01); H04W 8/04 (2009.01); H04W 60/04 (2009.01); H04W 60/06 (2009.01); H04W 76/02 (2009.01); H04W 68/00 (2009.01)
CPC H04W 36/0022 (2013.01) [H04L 65/1016 (2013.01); H04L 65/1069 (2013.01); H04L 65/1073 (2013.01); H04W 8/04 (2013.01); H04W 60/04 (2013.01); H04W 60/06 (2013.01); H04W 68/005 (2013.01); H04W 76/02 (2013.01); H04W 88/005 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method in a Mobile Switching Center (MSC) for controlling set up of a terminating call from an IP Multimedia Subsystem (IMS) to a User Equipment (UE) in a Circuit Switched Fallback (CSFB) situation, the MSC supporting IMS Centralized Services (ICS), the method comprising:
receiving, from the IMS, a terminating call set up request for the UE;
in response to reception of the terminating call set up request, sending a paging message to the UE;
subsequent to sending of the paging message, receiving a Send Identification message from a further MSC, the further MSC supporting ICS and the Send Identification message including an identification for the further MSC;
subsequent to sending of the paging message, receiving a Cancel Location message from a Home Location Register (HLR);
responsive to receiving the Send Identification message from the further MSC, forwarding the terminating call set up request to the further MSC;
subsequent to forwarding the terminating call set up request, relaying further messages related to ongoing calls of the UE between the further MSC and the IMS;
determining that all calls of the UE have ended; and
triggering de-registration of the UE from the IMS responsive to the determination that all calls of the UE have ended.