5.11 UE Power Limit Function (UPLF)
38.5093GPP5GSRelease 17Special conformance testing functions for User Equipment (UE)TS
5.11.1 General
The UE Power Limit Function is intended for the SS to communicate to the UE to apply a backoff of transmitted power on the NR primary component carrier when in FR2 carrier aggregation mode. On activation of this test function, the UE shall apply a configured power backoff on the primary component carrier to provide sufficient power head room for the other (secondary) component carrier(s). The UE power limit function is mandatory for applicable UEs operating in Frequency Range 2 (FR2) and supporting UL CA from Rel-16.
The SS uses the UE Power Limit test mode activation procedure to send a power limit request to the UE. The transmission from the SS shall be a vector of values, where the number of the reported values equals the back-off or power limit to be applied by the UE.
Figure 5.11.1-1: Activate Power Limit test mode procedure
Figure 5.11.1-2: Deactivate Power Limit test mode procedure
5.11.2 Activate Power Limit Procedure
5.11.2.1 Initiation
The SS requests the UE to apply the power limit by transmitting an ACTIVATE POWER LIMIT REQUEST message. The UE confirms that the power limit function is activated by sending an ACTIVATE POWER LIMIT RESPONSE.
5.11.2.2 Reception of ACTIVATE POWER LIMIT REQUEST by UE
When the UE receives the ACTIVATE POWER LIMIT REQUEST message, then the UE shall:
1> if the UE is operating in FR2 AND is in RRC_CONNECTED state:
2> UE limits power on PCell according to a back-off defined by Xmax,PCell.
1> else;
2> the UE behaviour is unspecified
The ACTIVATE POWER LIMIT REQUEST and ACTIVATE POWER LIMIT RESPONSE Message Octets Octets and power back-off Xmax,PCell are defined below in Section 6.11.
5.11.3 Deactivate Power Limit Procedure
5.11.3.1 Initiation
The SS requests the UE to deactivate from the power limit state by transmitting a DEACTIVATE POWER LIMIT REQUEST message. The SS should do this when the UE is in RRC_CONNECTED state.
5.11.3.2 Reception of DEACTIVATE POWER LIMIT REQUEST message by UE
When UE receives DEACTIVATE POWER LIMIT REQUEST message then the UE shall:
1> if the UE is operating in FR2 AND is in RRC_CONNECTED state AND the UE Power Limit test function is active:
2> Remove UE power limit on PCell and transmit DEACTIVATE POWER LIMIT RESPONSE message.
1> else:
2> the UE behaviour is unspecified.
5.11.3.3 Removal of power limits by UE
When the UE leaves the RRC_CONNECTED state, the UE shall:
1> if the UE is operating in FR2 AND the UE Power limit test Function is active
2> remove UE power limit on PCell;