scope:

The present document specifies the protocols for Proximity-based Services (ProSe) in 5G system as specified in 3GPP TS 23.304 [2] for:

a) 5G ProSe direct discovery;

b) 5G ProSe communication over the PC5 interface; and

c) 5G ProSe-enabled UE-to-network relay.

The present document defines the associated procedures for 5G ProSe service authorisation, 5G ProSe direct discovery (e.g. the procedures between 5G ProSe-enabled UE and 5G Direct Discovery Name Management Function (DDNMF) over the PC3a interface, the procedures over the PC5 interface), 5G ProSe UE-to-network relay discovery, and 5G ProSe direct communication.

The present document also defines the message format, message contents, error handling and system parameters applied by the protocols for ProSe in 5GS.