Mobile Terminated Short Message Service for Non-terrestrial Network Short Message Service Delivery

A system for delivering Mobile Terminated Short Message Service (MT-SMS) in a Non-Terrestrial Network (NTN), the system comprising:

• a short message service center;
• a routing agent;
• a NTN core network:
• an SMS delivery manager operating on the routing agent and the NTN core network to cause the routing agent and the NTN core network to:
• receive a mobile terminated forward short message request (TFR) from a short message service center (SMSC), wherein the TFR includes an SMS message and delivery information for a destination wireless device;
• store the delivery information associated with the TFR;
• compare the delivery information with previously stored delivery information of a previously received TFR and determining whether the TFR includes a new SMS message or an expired SMS message;
• forward the TFR to the NTN Core Network when the delivery information is determined to be associated with a new SMS message;
• and
• discard forwarding subsequent retry TFRs for retry TFRs received from the SMSC before receiving a mobile terminated forward short message answer (TFA) from the NTN Core Network. when the delivery information is determined to be associated with an expired SMS message.