A.7 Guidelines regarding use of conditions

38.3313GPPNRProtocol specificationRadio Resource Control (RRC)Release 15TS

Conditions are primarily used to specify network restrictions, for which the following types can be distinguished:

– Message Contents related constraints e.g. that a field B is mandatory present if the same message includes field A and when it is set value X.

– Configuration Constraints e.g. that a field D can only be signalled if field C is configured and set to value Y. (i.e. regardless of whether field C is present in the same message or previously configured).

The use of these conditions is illustrated by an example.

— /example/ ASN1START

RRCMessage-IEs ::= SEQUENCE {

fieldA FieldA OPTIONAL, — Need M

fieldB FieldB OPTIONAL, — Cond FieldAsetToX

fieldC FieldC OPTIONAL, — Need M

fieldD FieldD OPTIONAL, — Cond FieldCsetToY

nonCriticalExtension SEQUENCE {} OPTIONAL


— /example/ ASN1STOP

Conditional presence



The field is mandatory present if fieldA is included and set to valueX. Otherwise the field is optionally present, need R.


The field is optionally present, need M, if fieldC is configured and set to valueY. Otherwise the field is absent and the UE does not maintain the value