5.3.1 General

38.5093GPP5GSRelease 17Special conformance testing functions for User Equipment (UE)TS

Before a loop functionality can be exercised, the test loop needs to be closed; this is to be understood as the UE being instructed to start looping back received data packets. When looping back received data packets is not any longer required the loop should be re-opened; opening of a loop does not change the type of bearer being established by the UE test mode activation function (subclause 5.2.2).

To limit the number of special test functions, the concept of closing and opening a loop is also used as instruction to the UE to initiate/terminate other actions. An example of this is counting the received packets and reporting the number of received packets back to the SS; in the context of this utilisation closing a loop is to be understood as the UE being instructed to start counting the packets, whereas opening a loop should be understood as stop counting the packets. Other utilisation of the closing/opening a "test loop" test functionality can be specified if appropriate.

The UE test loop functions for 5GS are intended for:

– NR receiver and transmitter testing to disable application data transfer in downlink and uplink during SS UE measurements.

– NR layer 2 (MAC, RLC, PDCP, SDAP) and data radio bearer testing to generate data transfer in downlink and uplink.

– NR layer 2 (MAC, RLC, PDCP, SDAP) and sidelink data radio bearer testing to generate data transfer in sidelink.

– NR layer 2 (MAC, RLC, PDCP) and MBS radio bearer testing.

– 5GC and NR layer 3 testing to verify data transfer continuation over RRC and 5GC procedures.

– 5GC and NR layer 3 testing to verify data transfer over PC5 interface.

– 5GC NAS user-plane testing to verify uplink QoS flow descriptions handling.

– PC5-U testing to verify sidelink PC5 QoS flow descriptions handling.