SCell activation enhancement with assistance reference signal
A user equipment is configured to receive a reference signal when secondary cell (SCell is to be activated. The UE receives a secondary cell (SCell) activation indication for activating an SCell, receives a reference signal (RS) triggering indication for triggering an RS prior to an expected SCell activation period, performs measurements on the triggered RS and activates the SCell based on the RS measurements.
1 . One or more processors configured to perform operations comprising:
receiving a medium access control control element (MAC-CE) comprising at least five octets, wherein a first set of the at least five octets includes four octets comprising a reserved field and 31 secondary cell (SCell) activation fields each corresponding to an SCell index, wherein a second set of the at least five octets include one or more octets each comprising a reference signal (RS) triggering field to trigger an aperiodic tracking reference signal (TRS) using a radio resource control (RRC) configured TRS index;
performing measurements on the aperiodic TRS; and
activating one or more SCells based on the MAC-CE.
2 . The one or more processors of claim 1 , wherein the operations further comprise:
receiving a RRC configuration for the aperiodic TRS, the RRC configuration comprising a resource allocation and slot offset for the aperiodic TRS.
3 . The one or more processors of claim 1 , wherein the operations further comprise:
receiving a further MAC-CE for channel state information (CSI) resource activation.
4 . The one or more processors of claim 1 , wherein the operations further comprise:
receiving a scheduling downlink control information (DCI) for the MAC-CE.
5 . The one or more processors of claim 4 , wherein a slot offset between the scheduling DCI and transmission of the aperiodic TRS is indicated in the scheduling DCI or the MAC-CE.
6 . The one or more processors of claim 1 , wherein SCell activation and the aperiodic TRS triggering are indicated in an uplink (UL) DCI.
7 . The one or more processors of claim 1 , wherein the operations further comprise:
determining a first scheduling offset between the MAC-CE comprising the RS triggering field to transmission of the aperiodic TRS and a second scheduling offset between transmission of the aperiodic TRS to an expected activation of the SCell.
8 . The one or more processors of claim 7 , wherein one of the first scheduling offset or the second scheduling offset is reported as a capability to a device comprising the one or more processors or is defined by a standard.
9 . The one or more processors of claim 1 , wherein the aperiodic TRS is configured with a quasi co-location (QCL) relationship with a synchronization signal block (SSB) or a periodic tracking reference signal (P-TRS).
10 . The one or more processors of claim 1 , wherein an expected SCell activation period is 3 ms after a hybrid automatic repeat request (HARQ) acknowledgement (HARQ-ACK) transmission for SCell activation.
11 . The one or more processors of claim 1 , wherein the aperiodic TRS is one of an aperiodic (AP) tracking reference signal (TRS), a periodic (P) TRS, a semi-persistent (SP) TRS, an AP CSI-RS, a P CSI-RS or an SP CSI-RS.
12 . The one or more processors of claim 1 , wherein activating the SCell based on the measurements includes using the measurements for automatic gain control (AGC) adjustment, timing and frequency error tracking, beam refinement and control state information (CSI) measurements for the SCell.
13 . A user equipment (UE), comprising:
a transceiver configured to connect to a base station; and
one or more processors communicatively coupled to the transceiver and configured to perform operations comprising:
receiving a medium access control control element (MAC-CE) comprising at least five octets, wherein a first set of the at least five octets includes four octets comprising a reserved field and 31 secondary cell (SCell) activation fields each corresponding to an SCell index, for activating an SCell and wherein a second set of the at least five octets include one or more octets each comprising a reference signal (RS) triggering field to trigger an aperiodic tracking reference signal (TRS) using a radio resource control (RRC) configured TRS index
performing measurements on the aperiodic TRS; and
activating one or more SCells based on the MAC CE.
14 . The UE of claim 13 , wherein the operations further comprise:
receiving a RRC configuration for the aperiodic TRS, the RRC configuration comprising a resource allocation and slot offset for the aperiodic TRS.
15 . The UE of claim 13 , wherein the operations further comprise:
receiving a further MAC-CE for channel state information (CSI) resource activation.
16 . The UE of claim 13 , wherein the operations further comprise:
receiving a scheduling downlink control information (DCI) for the MAC-CE, the scheduling DCI including a field to trigger the aperiodic TRS of the SCell, wherein a slot offset between the scheduling DCI and transmission of the aperiodic TRS is indicated in the scheduling DCI or the MAC-CE.