E receives PDSCH and PDCCH (if the UE is configured to monitor PDCCH on this SCell) and is expected to be able to perform CQI measurements on that cell. The NG-RAN ensures that while PUCCH SCell (i.e., an SCell configured with PUCCH) is deactivated, SCells of the secondary PUCCH group (i.e., a group of SCells whose PUCCH signaling is associated with the PUCCH on the PUCCH SCell) are activated. The NG-RAN further ensures that SCells mapped to PUCCH SCell are deactivated before the PUCCH SCell is changed or removed. When reconfiguring the set of serving cells, SCells added to the set are initially deactivated and SCells which remain in the set (either unchanged or reconfigured) do not change their activation status. During handover, the SCells are deactivated. When band- width adaptation is configured, only one UL BWP for each uplink carrier and one DL BWP or only one DL/UL BWP pair can be active at any given time in an active serving cell, all other BWPs that the UE is configured with will be deactivated. The UE does not monitor the PDCCH and does not transmit on PUCCH, PRACH, and UL-SCH of the deactivated BWPs [8]. The SCell activation/deactivation is an efficient mechanism to reduce UE power consump- tion in addition to DRX. On a deactivated SCell, the UE neither receives downlink signals nor transmits any uplink signal. The UE is also not required to perform measurements on a deactivated SCell. Deactivated SCells can be used as pathloss reference for measurements in uplink power control. It is assumed that these measurements would be less frequent while the SCell is deactivated in order to conserve the UE power. On the other hand, for an acti- vated SCell, the UE performs normal activities for downlink reception and uplink transmis- sion. Activation and deactivation of SCells is controlled by the gNB. As shown in Fig. 2.32, the SCell activation/deactivation is performed when the gNB sends an activation/deactiva- tion command in the form of a MAC CE. A timer may also be used for automatic deactiva- tion, if no d