Recovery mechanism for secondary cell
Aspects of the present disclosure relate to wireless communications, and more particularly, to cell recovery techniques. One example method generally includes receiving, at a user-equipment (UE), at least one pilot signal via a secondary cell, receive, via a primary cell, a first message triggering reporting of at least one preferred beam for communication via the secondary cell, determining the preferred beam based on the at least one pilot signal, transmitting, via the primary cell, a report indicating the at least one preferred beam, and communicating data via the secondary cell and via the preferred beam.
1. A method for wireless communication at a base station (BS), comprising:
receiving, from a user equipment (UE) on a first cell, an indication that one or more channel measurements are to be reported for a second cell for which beam failure is detected;
transmitting a first message triggering reporting by the UE of at least one preferred beam for data communication at the BS on the second cell, the first cell being different than the second cell, wherein the first message is transmitted in response to the indication that the one or more channel measurements are to be reported;
receiving an indication of the at least one preferred beam; and
configuring a transmission configuration state in accordance with the at least one preferred beam for data communication on the second cell with the UE.
2. The method of claim 1 , wherein configuring the transmission configuration state comprises transmitting a second message on the first cell confirming activation of the transmission configuration state, and wherein the second message is transmitted during a preset time window starting from transmission of the first message.
3. The method of claim 1 , wherein the first message is transmitted during a preset time window starting from the reception of the indication that the one or more channel measurements are to be reported.
4. The method of claim 1 , wherein a scrambling sequence used to encode the first message indicates to the UE to report the at least one preferred beam.
5. The method of claim 1 , wherein a search space in which the first message is transmitted indicates to the UE to report the at least one preferred beam.
6. The method of claim 1 , wherein the first message comprises a physical downlink control channel (PDCCH).
7. The method of claim 1 , wherein the first message comprises downlink control information (DCI) having one or more bits indicating to the UE to report the at least one preferred beam.
8. The method of claim 1 , wherein configuring the transmission configuration state comprises transmitting a second message on the first cell confirming activation of the transmission configuration state.
9. The method of claim 8 , wherein the second message transmitted on the first cell comprises a PDCCH scrambled with a cell-radio network temporary identifier (C-RNTI) associated with the second cell.
10. The method of claim 8 , wherein the second message is transmitted via a control resource set of the first cell.
11. The method of claim 8 , wherein the second message comprises a medium access control (MAC)-control element (CE) indicating the confirmation of the transmission configuration state.
12. The method of claim 1 , wherein the first cell comprises a primary cell, and wherein the second cell comprises a secondary cell.
13. An apparatus for wireless communication at a base station (BS), comprising:
a transceiver;
a processor coupled to the transceiver, wherein the processor is configured to:
receive via the transceiver, from a user equipment (UE) on a first cell, an indication that one or more channel measurements are to be reported for a second cell for which beam failure is detected;
transmit via the transceiver a first message triggering reporting by the UE of at least one preferred beam for data communication at the BS on the second cell, the first cell being different than the second cell, wherein the first message is in response to the indication that the one or more channel measurements are to be reported; and
receive via the transceiver an indication of the at least one preferred beam; and
configure a transmission configuration state in accordance with the at least one preferred beam for data communication on the second cell with the UE.
14. The apparatus of claim 13 , wherein the first message is transmitted during a preset time window starting from the reception of the indication that the one or more channel measurements are to be reported.
15. The apparatus of claim 13 , wherein the processor is further configured to transmit, via the transceiver, a second message on the first cell confirming activation of the transmission configuration state, and wherein the second message is transmitted during a preset time window starting from transmission of the first message.
16. The apparatus of claim 13 , wherein a scrambling sequence used to encode the first message indicates to the UE to report the at least one preferred beam.
17. The apparatus of claim 13 , wherein a search space in which the first message is transmitted indicates to the UE to report the at least one preferred beam.
18. The apparatus of claim 13 , wherein the first message comprises a physical downlink control channel (PDCCH).
19. The apparatus of claim 13 , wherein the first message comprises downlink control information (DCI) having one or more bits indicating to the UE to report the at least one preferred beam.
20. The apparatus of claim 13 , wherein the processor is further configured to transmit, via the transceiver, a second message on the first cell confirming activation of the transmission configuration state.
21. The apparatus of claim 20 , wherein the second message transmitted on the first cell comprises a PDCCH scrambled with a cell-radio network temporary identifier (C-RNTI) associated with the second cell.
22. The apparatus of claim 20 , wherein the second message is transmitted via a control resource set of the first cell.
23. The apparatus of claim 20 , wherein the second message comprises a medium access control (MAC)-control element (CE) indicating the confirmation of the transmission configuration state.
24. The apparatus of claim 13 , wherein the first cell comprises a primary cell, and wherein the second cell comprises a secondary cell.
25. An apparatus for wireless communication at a base station (BS), comprising:
means for receiving, from a user equipment (UE) on a first cell, an indication that one or more channel measurements are to be reported for a second cell for which beam failure is detected;
means for transmitting a first message triggering reporting by the UE of at least one preferred beam for data communication at the BS on the second cell, the first cell being different than the second cell, wherein the first message is transmitted in response to the indication that the one or more channel measurements are to be reported;
means for receiving an indication of the at least one preferred beam; and
means for configuring a transmission configuration state in accordance with the at least one preferred beam for data communication on the second cell with the UE.
26. The apparatus of claim 25 , wherein the first cell comprises a primary cell, and wherein the second cell comprises a secondary cell.
27. A non-transitory computer-readable medium having instructions stored thereon that, when executed by a processor, cause the processor to:
receive, from a user equipment (UE) on a first cell, an indication that one or more channel measurements are to be reported for a second cell for which beam failure is detected;
transmit a first message triggering reporting by the UE of at least one preferred beam for data communication at a base station (BS) on the second cell, the first cell being different than the second cell, wherein the first message is transmitted in response to the indication that the one or more channel measurements are to be reported;
receive an indication of the at least one preferred beam; and
configure a transmission configuration state in accordance with the at least one preferred beam for data communication on the second cell with the UE.
28. The non-transitory computer-readable medium of claim 27 , wherein the first cell comprises a primary cell, and wherein the second cell comprises a secondary cell.