36.5093GPPEvolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Packet Core (EPC)Release 17Special conformance testing functions for User Equipment (UE)TS
User Equipment (UE) Test Loop functionality is a mandatory feature to support E-UTRA / EPC conformance testing. It forms part of the core requirements and thus has a direct impact on the design of the UE.
The test methods applied in RF Conformance Test Specification TS 36.521-1  and the test models used in Protocol Conformance Test Specifications TS 36.523-1  and TS 36.523-3  define the corresponding UE Test Loop functionality. The present specification describes the location of the data loop in the protocol stack as well as the procedure and specific messages to activate/deactivate the Test Loop functionality in the UE.