This document captures the study result of possible system enhancements to support applications that communicate with devices that are not reachable for a long period over the 3GPP IP connectivity and being able to support large number of such devices in the system without negatively affecting the system performance. In addressing the above, the following problem is studied:

• Downlink access for devices that are not reachable for a long period and the problems associated with such devices (e.g. packet discard when the UE sleeps, frequent retransmissions, load on the CN network, waste of radio resources and UE power when the network unnecessarily conveys retransmit packets, etc.). This study may propose and evaluate enhancements to the 3GPP system. Depending on conclusions, the study may also propose 3GPP enablers to be used by the service layer e.g. defined by other SDOs for downlink access to devices that are not reachable for a long period.

Different application layer protocols used within the M2M ecosystem have different requirements and characteristics with respect to acceptable end-to-end delay, round trip time, persistence in retransmissions, etc. The result of this study may include general recommendations for application layers how to use the 3GPP accesses for better application performance and optimal core and radio network efficiency thereof.

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

• References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.