Apparatuses and methods for enabling secondary cell group (SCG) suspension and resumption or primary secondary cell (PSCell) deactivation and activation
A method, executed by a User Equipment (UE) communicatively connected to a Secondary Cell Group (SCG) of a mobile communication network, is provided. The method includes the following steps: receiving a first Radio Resource Control (RRC) message or a Media Access Control (MAC) Control Element (CE) including an indicator for suspension or resumption of the SCG or for deactivation or activation of a Primary Secondary Cell (PSCell) of the SCG from the mobile communication network; suspending SCG transmission for all radio bearers in response to the first RRC message or the MAC CE including an indicator for suspension of the SCG or deactivation of the PSCell; and resuming SCG transmission for all radio bearers in response to the first RRC message or the MAC CE including an indicator for resumption of the SCG or activation of the PSCell.
1 . A User Equipment (UE), comprising:
a wireless transceiver, configured to perform wireless transmission and reception to and from a Secondary Cell Group (SCG) of a mobile communication network; and
a controller, configured to:
in response to the UE being in an RRC_INACTIVE mode and the SCG being suspended, perform early measurement which includes measurement on the cells of the SCG and send a Radio Resource Control (RRC) Resume Request message to the mobile communication network to initiate a RRC connection resume procedure, wherein the early measurement is performed before starting the RRC connection resume procedure;
in response to sending the RRC Resume Request message, receive a RRC Resume message comprising a first indicator for the UE to keep the SCG suspended and an idleModeMeasurementReq Information Element (IE) for requesting the result of the early measurement from the mobile communication network via the wireless transceiver;
keep the SCG suspended in response to the RRC Resume message comprising the first indicator;
send an RRC Resume Complete message comprising measurement results of a Primary Secondary Cell (PSCell) of the SCG to the mobile communication network via the wireless transceiver;
configure the UE to enter an RRC_CONNECTED mode from the RRC_INACTIVE mode in response to sending the RRC Resume Complete message;
after the UE enters the RRC_CONNECTED mode, receive an RRC Reconfiguration message or a Media Access Control (MAC) Control Element (CE) comprising a second indicator for resumption of the SCG from the mobile communication network via the wireless transceiver;
resume SCG transmission for all radio bearers in response to the RRC Reconfiguration message or the MAC CE comprising the second indicator;
activate the PSCell and performing a Random Access (RA) procedure on the PSCell in response to the RRC Reconfiguration message or the MAC CE comprising the second indicator; and
start Physical Downlink Control Channel (PDCCH) monitoring for the PSCell in response to activating the PSCell.
2 . A method, executed by a User Equipment (UE) communicatively connected to a Secondary Cell Group (SCG) of a mobile communication network, comprising:
in response to the UE being in an RRC_INACTIVE mode and the SCG being suspended, performing early measurement which includes measurement on the cells of the SCG and sending a Radio Resource Control (RRC) Resume Request message to the mobile communication network to initiate a RRC connection resume procedure, wherein the early measurement is performed before starting the RRC connection resume procedure;
in response to sending the RRC Resume Request message, receiving a RRC Resume message comprising a first indicator for the UE to keep the SCG suspended and an idleModeMeasurementReq Information Element (IE) for requesting the result of the early measurement from the mobile communication network;
keeping the SCG suspended in response to the RRC Resume message comprising the first indicator;
sending an RRC Resume Complete message comprising measurement results of a Primary Secondary Cell (PSCell) of the SCG to the mobile communication network;
entering an RRC_CONNECTED mode from the RRC_INACTIVE mode in response to sending the RRC Resume Complete message;
after entering the RRC_CONNECTED mode, receiving an RRC Reconfiguration message or a Media Access Control (MAC) Control Element (CE) comprising a second indicator for resumption of the SCG from the mobile communication network;
resuming SCG transmission for all radio bearers in response to the RRC Reconfiguration message or the MAC CE comprising the second indicator;
activating the PSCell and performing a Random Access (RA) procedure on the PSCell in response to the RRC Reconfiguration message or the MAC CE comprising the second indicator; and
starting Physical Downlink Control Channel (PDCCH) monitoring for the PSCell in response to activating the PSCell.