Device reachability in lte networks for text messaging

A method comprising:

• attempting delivery of a text message from a message entity of a Long Term Evolution (LTE) network to a mobile device,
• determining that the delivery attempt failed due to the mobile device being unavailable;
• transmitting a request from the message entity directly to a Mobility Management Entity (MME) of the LTE network to be notified when the mobile device becomes available, wherein the message entity connects to the MME over an interface in the LTE network;
• receiving a notification in the message entity directly from the MME that the mobile device is available;
• and
• retrying delivery of the text message to the mobile device responsive to the notification from the MME that the mobile device is available.

An apparatus comprising:

• a Mobility Management Entity (MME) for serving a mobile device of a Long Term Evolution (LTE) network;
• the MME configured to receive a text message from a message entity that is intended for the mobile device, to attempt delivery of the text message to the mobile device, and to send a response to the message entity indicating that the delivery attempt failed due to the mobile device being unavailable when the delivery attempt failed;
• the MME further configured to receive a request directly from the message entity to be notified when the mobile device becomes available, and to monitor a status of the mobile device;
• and
• the MME further configured to transmit, in response to the mobile device becoming available, a notification directly to the message entity that the mobile device is available to initiate a delivery retry;
• the MME is further configured to directly connect to the message entity over a Diameter S6 interface in the LTE network.