23.1423GPPInterface and signalling flowRelease 17TSValue-added Services for SMS (VAS4SMS)
Short Message Personal Signature service is applicable for the originating user. In this case, the VAS AS checks that the originating user has activated the Short Message Personal Signature service and shall append the user’s personal signature to the short message. The Short Message Personal Signature procedure refers to the general procedure for VAS SMS which described in the previous clause 7.0.
Short message personal signature should be appended in the last concatenated message for a large message need to be separated into concatenated messages.