Section: 5.13 Activation/Deactivation of SCells
Content: If the MAC entity is configured with one or more SCells, the network may activate and deactivate the configured SCells. The SpCell is always activated. The network activates and deactivates the SCell(s) by sending Activation/Deactivation and/or Hibernation MAC control element(s) described in clause 6.1.3.8 and 6.1.3.15 respectively. Furthermore, the MAC entity maintains a sCellDeactivationTimer timer per configured SCell (except the SCell configured with PUCCH/SPUCCH, if any) and deactivates the associated SCell upon its expiry. In case the sCellHibernationTimer is configured, it takes priority over sCellDeactivationTimer. The same initial timer value applies to each instance of the sCellDeactivationTimer and it is configured by RRC. The configured SCells are initially deactivated upon addition and after a handover unless the parameter sCellState is set to activated or dormant for the SCell within RRC configuration. The configured SCG SCells are initially deactivated after a SCG change unless the parameter sCellState is set to activated or dormant for the SCell within RRC configuration. The MAC entity shall for each TTI and for each configured SCell: - if the MAC entity is configured with an activated SCell upon SCell configuration or receives MAC control element(s) in this TTI activating the SCell, the MAC entity shall in the TTI according to the timing defined in TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2]: - activate the SCell; i.e. apply normal SCell operation including: - SRS transmissions on the SCell; - if cqi-ShortConfigSCell is configured: - CQI/PMI/RI/PTI/CRI reporting for the SCell using the short period of the CSI (CQI/PMI/RI/PTI/CRI) reporting resource configured by cqi-ShortConfigSCell according to the timing defined in TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2]. - else: - CQI/PMI/RI/PTI/CRI reporting for the SCell using the configuration in cqi-ReportConfigSCell. - PDCCH monitoring on the SCell; - PDCCH monitoring for the SCell; - PUCCH/SPUCCH transmissions on the SCell, if configured. - start or restart the sCellDeactivationTimer associated with the SCell; - if sCellHibernationTimer associated with the SCell is configured; - start or restart the sCellHibernationTimer associated with the SCell. - trigger PHR according to clause 5.4.6. - else, if the MAC entity receives MAC control element(s) in this TTI deactivating the SCell; or - if the sCellDeactivationTimer associated with the activated SCell expires in this TTI and sCellHibernationTimer is not configured: - in the TTI according to the timing defined in TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2]: - deactivate the SCell; - stop the sCellDeactivationTimer associated with the SCell; - clear any configured downlink assignments and uplink grants associated with the SCell; - flush all HARQ buffers associated with the SCell. - if PDCCH on the activated SCell indicates an uplink grant or downlink assignment; or - if PDCCH on the Serving Cell scheduling the activated SCell indicates an uplink grant or a downlink assignment for the activated SCell; or - if a MAC PDU is transmitted in a configured uplink grant or received in a configured downlink assignment: - restart the sCellDeactivationTimer associated with the SCell; - if sCellHibernationTimer associated with the SCell is configured; - restart the sCellHibernationTimer associated with the SCell; - if the SCell is activated and the cqi-ShortConfigSCell expires in this TTI, according to the timing defined in TS 36.213[ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures ]  [2]: - apply SCell CQI/PMI/RI/PTI/CRI reporting for the SCell using the configuration in cqi-ReportConfigSCell; - if the SCell is deactivated: - not transmit SRS on the SCell; - not report CQI/PMI/RI/PTI/CRI for the SCell; - not transmit on UL-SCH on the SCell; - not transmit on RACH on the SCell; - not monitor the PDCCH on the SCell; - not monitor the PDCCH for the SCell; - not transmit PUCCH/SPUCCH on the SCell. HARQ feedback for the MAC PDU containing Activation/Deactivation MAC control element shall not be impacted by PCell, PSCell and PUCCH SCell interruptions due to SCell activation/deactivation, as specified in TS 36.133[ Evolved Universal Terrestrial Radio Access (E-UTRA); Requirements for support of radio resource management ]  [9]. NOTE: When SCell is deactivated, the ongoing Random Access procedure on the SCell, if any, is aborted.