scope:

The present document specifies the Stage 2 of the Proximity Services (ProSe) features in EPS. ProSe features consist of: ProSe discovery (direct or EPC-level) and ProSe Direct Communication.

ProSe discovery identifies that ProSe-enabled UEs are in proximity, using E-UTRAN (with or without E-UTRAN), WLAN technology or EPC. The details of WLAN-based ProSe Direct Discovery are described in clause 5.3.1.3 and Annex C.

ProSe Direct Communication enables establishment of communication paths between two or more ProSe-enabled UEs that are in direct communication range. The ProSe Direct Communication path could use E-UTRAN or WLAN.

For Public Safety specific usage:

- ProSe-enabled Public Safety UEs can establish the communication path directly between two or more ProSeenabled Public Safety UEs, regardless of whether the ProSe-enabled Public Safety UE is served by E-UTRAN.

- ProSe Direct Communication is also facilitated by the use of a ProSe UE-to-Network Relay, which acts as a relay between E-UTRAN and UEs.

Security aspects of ProSe are defined in TS 33.303 [29].