Circuit-switched services over SAE/LTE networks

An apparatus in a Mobility Management Entity (MME) in an SAE core network for providing a circuit-switched (CS) service to a User Equipment (UE) through the SAE core network and an LTE radio access network said apparatus comprising:

• a processor;
• and
• a memory containing instructions executable by said processor, whereby said apparatus is operative to:
• utilize an extended SGs interface (SGs+) with a Mobile Switching Center Server (MSC-S) in a CS core network to send and receive SGs+ messages, wherein the SGs+ interface supports transmission of upper layer packet data units, wherein utilizing the SGs+ interface includes transferring CS service messages in SGs+ messages sent over the SGs+ interface;
• and
• transfer CS service message contents between the MME and the UE via the LTE radio access network,
• wherein the CS service is a Short Message Service (SMS) and the transfer of CS service messages Includes receiving from the MSC-S, an SGs+ downlink data transfer message, said SGs+ downlink data transfer message comprising SMS message content for delivery to a terminating UE.

A system for providing a circuit switched (CS) service to a User Equipment (UE) through an SAE core network and an LTE radio access network, said system comprising:

• a Mobility Management Entity (MME) in the SAE core network;
• a Mobile Switching Center Server (MSC-S) in a CS core network;
• and
• an extended SGs interface (SGs+) for sending and receiving SGs+ messages between the MME and the MSC-S, wherein the SGs+ interface supports transmission of upper layer packet data units in CS service messages;
• wherein the MME and the MSC-S are operative to utilize the SGs+ interface to transfer CS service messages in SGs+ uplink and downlink data transfer messages sent over the SGs+ interface;
• and
• wherein the CS service is a Short Message Service (SMS) and utilizing the SGs+ interface includes sending and receiving SGs+ uplink and downlink data transfer messages that include SMS message content.