scope:

The present document specifies the protocols for application layer support for UAS services as specified in 3GPP TS 23.255 [2] for:

a) UAS application communication between the UE and the UAE server (over the U1-AE interface); and

b) UAS application communication among UEs (over the U1-AE interface using unicast Uu).

The present specification defines the associated procedures for UAS application communication between the UE and the UAE server and among UEs.

The present specification defines the usage and interactions of the UAE layer with SEAL services.

The present specification also defines the message format, message contents, error handling and system parameters applied by the protocols for the UAE layer.