The network configures the UE with Master Cell Group (MCG), and zero or one Secondary Cell Group (SCG). In (NG)EN-DC, the MCG is configured as specified in TS 36.331, and for NE-DC, the SCG is configured as specified in TS 36.331. The network provides the configuration parameters for a cell group in the CellGroupConfigIE.
The UE performs the following actions based on a received CellGroupConfigIE:
resume all suspended radio bearers except the SRBs for the source cell group, and resume SCG transmission for all radio bearers, and resume BH RLC channels and resume SCG transmission for BH RLC channels for IAB-MT, if suspended;
if the AS security is not activated, perform the actions upon going to RRC_IDLE as specified in clause 5.3.11 with the release cause 'other' upon which the procedure ends;
start timer T430 with the timer value set to ntn-UlSyncValidityDuration from the subframe indicated by epochTime, according to the target cell NTN-config;
if this procedure is executed for the MCG or if this procedure is executed for an SCG not indicated as deactivated in the E-UTRA or NR RRC message in which the RRCReconfiguration message is embedded:
configure lower layers for the target SpCell in accordance with any additional fields, not covered in the previous, if included in the received reconfigurationWithSync.
consider the SCell(s) of this cell group, if configured, that are not included in the SCellToAddModList in the RRCReconfiguration message, to be in deactivated state;
indicate upper layer to trigger PC5 unicast link release.
Upon L2 U2N Relay UE receiving reconfigurationWithSync, it either indicates to upper layers (to trigger PC5 unicast link release) or sends Notification message to the connected L2 U2N Remote UE(s) in accordance with clause 5.8.9.10.
for each logicalChannelIdentity/LogicalChannelIdentityExt value included in the rlc-BearerToReleaseList/rlc-BearerToReleaseListExt that is part of the current UE configuration within the same cell group (LCH release); or
if the UE's current configuration contains an RLC bearer with the received logicalChannelIdentity/LogicalChannelIdentityExt within the same cell group:
else (a logical channel with the given logicalChannelIdentity/LogicalChannelIdentityExt is not configured within the same cell group, including the case when full configuration option is used):
reconfigure the MAC main configuration for the target cell group in accordance with the received mac-CellGroupConfig excluding tag-ToReleaseList and tag-ToAddModList;
reconfigure the MAC main configuration of the cell group in accordance with the received mac-CellGroupConfig excluding tag-ToReleaseList and tag-ToAddModList;
consider the bandwidth part indicated in firstActiveDownlinkBWP-Id to be the bandwidth part for Radio Link Monitoring, Beam Failure Detection and measurements;
for each BH-RLC-ChannelID value included in the bh-RLC-ChannelToReleaseList that is part of the current IAB-node configuration within the same cell group (LCH release); or
for each Uu-RelayRLC-ChannelID value included in the uu-RelayRLC-ChannelToReleaseList that is part of the current configuration within the same cell group (LCH release):