SUPPORT OF SHORT MESSAGE SERVICE IN IMS WITHOUT MSISDN

The application relates to Short Message Service SMS in IMS. The relevant standard is 3GPP TR 23.863. According to current standardised procedures, a UE in an originating network can submit an encapsulated SMS to an S-CSCF which forwards it to an IP-SM-GW in the originating network. The IP-SM-GW can extract the SMS and forward it to an SMS-SC. The SMS-SC can forward the SMS to an SMS-GMSC in the terminating network which delivers it to an IP-SM-GW in the terminating network. The can use the telephone uniform resource identifier associated with the IMSI of the message received for the target UE to send the short message encapsulated in the appropriate SIP method towards an S-CSCF which forwards it to the target UE. If the target UE is available via IMS forwarding via the SMS-SC is unnecessary. Therefore, the present application proposes to deliver a SIP message (S16) with encapsulated SMS content from the IP-SM-GW (300) in the originating network directly to an IP-SM-GW (500) in the terminating network without the usage of the SMS-SC.