SMS technology has been specified by the ETSI in GSM 03.40 and 03.38 documents (3GPP TS 23.040 and 3GPP TS 23.038 respectively). These documents only describe how to use SMS over mobile networks (nothing for IP networks).
In real world there are two way to receive SMS messages over mobile networks: Binary (PDU) and Text mode.
In this post I will explain how to use SMS technology over IP within the IP Multimedia (IM) Core Network (CN) subsystem based on the Session Initiation Protocol (SIP) and SIP Events as defined in 3GPP TS 24.229.
Note: In the coming chapters, « SMS over IMS Network » and « SMS over IP Network » have the same meaning.
The message payload is transfered « as is ». This mode is out of scope.
GSM 7 bit Default Alphabet
Each character represent 7bits. For more information see 3GPP TS 23.038 or ETSI GSM 03.38.
Figure 1: GSM 7bit alphabet
Mobile-Originated SMS (MO-SMS)
** [1,2,4] RP-DATA (SMS-SUBMIT)
** [9,10,11] RP-ACK(SMS-SUBMIT-REPORT)
Mobile-Terminated SMS (MT-SMS)
** [2,3,4] RP-DATA(SMS-DELIVER)
The payload includes the RP-DATA message. Its RP-User-Data information element includes a TPDU of type SMS-DELIVER.
** [8,9,11] RP-ACK(SMS-DELIVER-REPORT)
The payload includes an RP-ACK message. Its RP-User-Data information element includes a TPDU of type SMS-DELIVER-REPORT.
If error occurs when decoding the message, RP-ERROR (3GPP TS 24.011 subclause 7.3.4) message is sent instead of RP-ACK.
- 3GPP TS 23.038 - Alphabets and language-specific information
- 3GPP TS 23.040 - Technical realization of Short Message Service (SMS)
- 3GPP TS 24.011 - Point-to-Point (PP) Short Message Service (SMS) support on mobile radio interface.
- 3GPP TS 24.341 - Support of SMS over IP networks; Stage 3
- 3GPP TS 24.451 - Support of SMS and MMS over NGN IMS subsystem; Stage 3 [Endorsement of 3GPP TS 24.341 Release 7]