Fast secondary cell activation with temporary reference signals
A user equipment (UE) configured to receive secondary cell (SCell) activation configuration information from a first cell, receive a medium access control (MAC) control element (CE) from the first cell, wherein the MAC CE indicates that a SCell state is to be changed from a deactivated state to an activated state and receive aperiodic reference signals from a secondary cell (SCell), wherein the reception of the aperiodic reference signals is triggered by the MAC CE.
1. A processor of a user equipment (UE) configured to perform operations comprising:
receiving secondary cell (SCell) activation configuration information from a first cell;
receiving a medium access control (MAC) control element (CE) from the first cell, wherein the MAC CE indicates that a SCell state is to be changed from a deactivated state to an activated state, wherein the MAC CE comprises a single-octet bitmap comprising seven C i fields and one reserved bit, and wherein a C i field indicates an activation status of a SCell with SCell index i; and
receiving aperiodic reference signals from a secondary cell (SCell), wherein the reception of the aperiodic reference signals is triggered by the MAC CE, and wherein the MAC CE comprises a trigger state (TS) field common to all component carriers (CCs) and indicates whether each CC is to utilize SCell activation with aperiodic reference signals or a synchronization signal block (SSB) based SCell activation.
2. The processor of claim 1 , the operation further comprising:
determining that a second different SCell is to be activated using a synchronization signal block (SSB) approach based on a value of a C i field and a value of a trigger state (TS) field included in the MAC CE.
3. The processor of claim 2 , wherein the TS field in the MAC CE consists of two bits,
wherein a TS field value of 00 indicates that no aperiodic reference signal (RS) is triggered for SCell activation and the SSB approach is to be used for SCell activation,
wherein a TS field value of 01 indicates that the aperiodic RS resource set associated with TS value of 01 was triggered,
wherein a TS field value of 10 indicates that the aperiodic RS resource set associated with TS value of 10 was triggered, and
a TS field value of 01 indicates that the aperiodic RS resource set associated with TS value of 01 was triggered.
4. The processor of claim 1 , wherein the MAC CE comprises a trigger state (TS) field common to all component carriers (CCs), multiple bitmap flag fields (F i ) each corresponding to a CC index (i) and multiple (C i ) fields,
wherein a F i field value of 1 is associated with an aperiodic reference signal (RS) triggered by the MAC CE for SCell activation, and
wherein a F i field value of 0 is associated with a periodic synchronization signal block (SSB) for SCell activation.
5. The processor of claim 1 , the operations further comprising:
receiving, separately from the aperiodic reference signals, aperiodic channel state information (CSI)-reference signal (RS), and
wherein the aperiodic reference signals are tracking reference signals (TRS).
6. The processor of claim 5 , wherein the MAC CE triggers the reception of the aperiodic CSI-RS.
7. The processor of claim 5 , the operations further comprising:
receiving downlink control information (DCI) over a physical downlink control channel PDCCH),
wherein the PDCCH schedules a physical downlink shared channel (PDSCH) comprising the MAC CE, and
wherein the DCI comprises an information element (IE) triggering the reception of the aperiodic CSI-RS.
8. The processor of claim 1 , wherein the SCell activation configuration information comprises a reference signal burst number and the MAC CE comprises the reference signal burst number, the operations further comprising:
determining the reference signal burst number is invalid; and
operating the UE based on a Release 16 (Rel-16) SSB based SCell activation scheme.
9. The processor of claim 8 , wherein the determining the reference signal burst number is invalid is based on at least a table stored on the UE.
10. A processor of a base station configured to perform operations comprising:
generating, for transmission to a user equipment (UE), secondary cell (SCell) activation configuration information;
generating, for transmission to the UE, a medium access control (MAC) control element (CE) from a cell, wherein the MAC CE indicates that a SCell state is to be changed from a deactivated state to an activated state, wherein the reception of aperiodic reference signals at the UE is triggered by the MAC CE, wherein the MAC CE comprises a single-octet bitmap comprising seven C i fields and one reserved bit, wherein a C i field indicates an activation status of a SCell with SCell index i, and wherein the MAC CE comprises a trigger state (TS) field common to all component carriers (CCs) and indicates whether each CC is to utilize SCell activation with aperiodic reference signals or a synchronization signal block (SSB) based SCell activation; and
receiving hybrid automatic repeat request (HARQ) feedback from the UE in response to the MAC CE.
11. The processor of claim 10 , the operation further comprising:
determining that a second different SCell is to be activated using a synchronization signal block (SSB) approach based on a value of a C i field and a trigger state included in the MAC CE.
12. A user equipment (UE), comprising:
a transceiver configured to communicate with a network; and
a processor communicatively coupled to the transceiver and configured to perform operations comprising:
receiving secondary cell (SCell) activation configuration information from a first cell;
receiving a medium access control (MAC) control element (CE) from the first cell, wherein the MAC CE indicates that a SCell state is to be changed from a deactivated state to an activated state, wherein the MAC CE comprises a single-octet bitmap comprising seven C i fields and one reserved bit, and wherein a C i field indicates an activation status of a SCell with SCell index i; and
receiving aperiodic reference signals from a secondary cell (SCell), wherein the reception of the aperiodic reference signals is triggered by the MAC CE, and wherein the MAC CE comprises a trigger state (TS) field common to all component carriers (CCs) and indicates whether each CC is to utilize SCell activation with aperiodic reference signals or a synchronization signal block (SSB) based SCell activation.
13. The UE of claim 12 , the operations further comprising:
determining that a second different SCell is to be activated using a synchronization signal block (SSB) approach based on a value of a GÅ field and a value of a trigger state (TS) field included in the MAC CE.
14. The UE of claim 13 , wherein the TS field in the MAC CE consists of two bits,
wherein a TS field value of 00 indicates that no aperiodic reference signal (RS) is triggered for SCell activation and the SSB approach is to be used for SCell activation,
wherein a TS field value of 01 indicates that the aperiodic RS resource set associated with TS value of 01 was triggered,
wherein a TS field value of 10 indicates that the aperiodic RS resource set associated with TS value of 10 was triggered, and
a TS field value of 01 indicates that the aperiodic RS resource set associated with TS value of 01 was triggered.
15. The UE of claim 12 , wherein the SCell activation configuration information comprises a reference signal burst number and the MAC CE comprises the reference signal burst number, the operations further comprising:
determining the reference signal burst number is invalid; and
operating the UE based on a Release 16 (Rel-16) SSB based SCell activation scheme.
16. The UE of claim 15 , wherein the determining the reference signal burst number is invalid is based on at least a table stored on the UE.