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, 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 of at least one preferred beam for communicating on the second cell, the first cell being different from 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 a report indicating the at least one preferred beam; and configuring a transmission configuration state in accordance with the at least one preferred beam for communicating on the second cell.
1. An apparatus for wireless communication at a communications device, comprising:
a memory; and
one or more processors coupled to the memory, wherein the one or more processors are configured to cause the communications device to:
receive, 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 that triggers reporting of at least one preferred beam for communication on the second cell, wherein:
the first cell is different from the second cell, and
the first message is transmitted in response to the indication that the one or more channel measurements are to be reported;
receive a report that indicates the at least one preferred beam; and
configure a transmission configuration state in accordance with the at least one preferred beam for communication on the second cell.
2. The apparatus of claim 1 , wherein:
to configure the transmission configuration state, the one or more processors are further configured to cause the communications device to transmit a second message on the first cell, and
the second message confirms reconfiguration of the transmission configuration state.
3. The apparatus of claim 2 , wherein the second message transmitted on the first cell comprises a physical downlink control channel (PDCCH) scrambled with a cell-radio network temporary identifier (C-RNTI) associated with the second cell.
4. The apparatus of claim 2 , wherein to transmit the second message, the one or more processors are configured to cause the communications device to transmit the second message via a control resource set on the first cell.
5. The apparatus of claim 2 , wherein the second message comprises a media access control-control element (MAC-CE) that indicates the reconfiguration of the transmission configuration state.
6. The apparatus of claim 2 , wherein the one or more processors are further configured to cause the communications device to communicate with a user equipment (UE) via the at least one preferred beam on the second cell in accordance with the reconfiguration of the transmission configuration state.
7. The apparatus of claim 1 , wherein:
to transmit the first message, the one or more processors are configured to cause the communications device to transmit the first message during a preset time window, and
the preset time window starts from reception of the indication that the one or more channel measurements are to be reported.
8. The apparatus of claim 1 , wherein a scrambling sequence applied to encode the first message indicates to a user equipment (UE) to report the at least one preferred beam.
9. The apparatus of claim 1 , wherein a search space in which the first message is transmitted indicates to a user equipment (UE) to report the at least one preferred beam.
10. The apparatus of claim 1 , wherein the first message comprises a physical downlink control channel (PDCCH).
11. The apparatus of claim 1 , wherein the first message comprises downlink control information (DCI) having one or more bits that indicate to a user equipment (UE) to report the at least one preferred beam.
12. The apparatus of claim 1 , wherein to receive the report, the one or more processors are further configured to cause the communications device to receive the report that indicates the at least one preferred beam via a media access control-control element (MAC-CE).
13. The apparatus of claim 1 , wherein:
the report includes a beam index associated with the at least one preferred beam, and
to receive the report, the one or more processors are further configured to cause the communications device to receive the report via a media access control-control element (MAC-CE).
14. The apparatus of claim 1 , wherein:
the at least one preferred beam includes a plurality of preferred beams;
the report that indicates the at least one preferred beam includes a plurality of beam indices associated with the plurality of preferred beams; and
the one or more processors are further configured to cause the communications device to receive the report that indicates the at least one preferred beam via a media access control-control element (MAC-CE).
15. A method for wireless communication at a base station (BS), comprising:
receiving, 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 that triggers reporting of at least one preferred beam for communicating on the second cell, wherein:
the first cell is different from the second cell, and
the first message is transmitted in response to the indication that the one or more channel measurements are to be reported;
receiving a report that indicates the at least one preferred beam; and
configuring a transmission configuration state in accordance with the at least one preferred beam for communication on the second cell.
16. The method of claim 15 , wherein:
configuring the transmission configuration state comprises transmitting a second message on the first cell, and
the second message confirms reconfiguration of the transmission configuration state.
17. The method of claim 16 , wherein the second message transmitted on the first cell comprises a physical downlink control channel (PDCCH) scrambled with a cell-radio network temporary identifier (C-RNTI) associated with the second cell.
18. The method of claim 16 , wherein the second message is transmitted via a control resource set on the first cell.
19. The method of claim 16 , wherein the second message comprises a media access control-control element (MAC-CE) that indicates the reconfiguration of the transmission configuration state.
20. The method of claim 16 , further comprising communicating with a user equipment (UE) via the at least one preferred beam on the second cell in accordance with the reconfiguration of the transmission configuration state.
21. The method of claim 15 , wherein the first message is transmitted during a preset time window starting from reception of the indication that the one or more channel measurements are to be reported.
22. The method of claim 15 , wherein a scrambling sequence applied to encode the first message indicates to a user equipment (UE) to report the at least one preferred beam.
23. The method of claim 15 , wherein a search space in which the first message is transmitted indicates to a user equipment (UE) to report the at least one preferred beam.
24. The method of claim 15 , wherein the first message comprises a physical downlink control channel (PDCCH).
25. The method of claim 15 , wherein the first message comprises downlink control information (DCI) having one or more bits that indicate to a user equipment (UE) to report the at least one preferred beam.
26. The method of claim 15 , wherein receiving the report that indicates the at least one preferred beam is received comprises receiving the report via a media access control-control element (MAC-CE).
27. The method of claim 15 , wherein:
the report includes a beam index associated with the at least one preferred beam, and
receiving the report comprises receiving the report via a media access control-control element (MAC-CE).
28. The method of claim 15 , wherein:
the at least one preferred beam includes a plurality of preferred beams;
the report that indicates the at least one preferred beam includes a plurality of beam indices associated with the plurality of preferred beams; and
receiving the report indicating the at least one preferred beam comprises receiving the report via a media access control-control element (MAC-CE).
29. An apparatus for wireless communication, comprising:
means for receiving, 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 that triggers reporting of at least one preferred beam for communication on the second cell, wherein:
the first cell is different from the second cell, and
the first message is transmitted in response to the indication that the one or more channel measurements are to be reported;
means for receiving a report that indicates the at least one preferred beam; and
means for configuring a transmission configuration state in accordance with the at least one preferred beam for communication on the second cell.
30. The apparatus of claim 29 , wherein the report includes a beam index associated with the at least one preferred beam.
31. The apparatus of claim 29 , wherein the first message comprises a physical downlink control channel (PDCCH).
32. The apparatus of claim 29 , wherein the first message comprises downlink control information (DCI) having one or more bits that indicate to a user equipment (UE) to report the at least one preferred beam.
33. The apparatus of claim 29 , wherein:
to configure the transmission configuration state, the means for configuring the transmission configuration state comprise means for transmitting a second message on the first cell, and
the second message confirms reconfiguration of the transmission configuration state.
34. The apparatus of claim 33 , wherein the second message transmitted on the first cell comprises a physical downlink control channel (PDCCH) scrambled with a cell-radio network temporary identifier (C-RNTI) associated with the second cell.
35. The apparatus of claim 33 , wherein the means for configuring the transmission configuration state comprise means for transmitting the second message via a control resource set on the first cell.
36. The apparatus of claim 29 , wherein the means for receiving the report that indicates the at least one preferred beam comprise means for receiving the report via a media access control-control element (MAC-CE).
37. The apparatus of claim 29 , wherein:
the report includes a beam index associated with the at least one preferred beam, and
to receive the report, the means for receiving the report that indicates the at least one preferred beam comprise means for receiving the report via a media access control-control element (MAC-CE).
38. The apparatus of claim 29 , wherein:
the at least one preferred beam includes a plurality of preferred beams;
the report that indicates the at least one preferred beam includes a plurality of beam indices associated with the plurality of preferred beams; and
the means for receiving the report comprise means for receiving the report that indicates the at least one preferred beam via a media access control-control element (MAC-CE).
39. A non-transitory computer-readable medium for wireless communication at a communications device, comprising:
executable instructions that, when executed by one or more processors, cause the communications device to:
receive, 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 that triggers reporting of at least one preferred beam for communicating on the second cell, wherein:
the first cell is different from the second cell, and
the first message is transmitted in response to the indication that the one or more channel measurements are to be reported;
receive a report indicating the at least one preferred beam; and
configure a transmission configuration state in accordance with the at least one preferred beam for communicating on the second cell.
40. The non-transitory computer-readable medium of claim 39 , wherein the report includes a beam index associated with the at least one preferred beam.
41. The non-transitory computer-readable medium of claim 39 , wherein the first message comprises a physical downlink control channel (PDCCH).
42. The non-transitory computer-readable medium of claim 39 , wherein the first message comprises downlink control information (DCI) having one or more bits that indicate to a user equipment (UE) to report the at least one preferred beam.
43. The non-transitory computer-readable medium of claim 39 , wherein:
to configure the transmission configuration state, the executable instructions, when executed by the one or more processors, further cause the communications device to transmit a second message on the first cell, and
the second message confirms reconfiguration of the transmission configuration state.
44. The non-transitory computer-readable medium of claim 43 , wherein the second message transmitted on the first cell comprises a physical downlink control channel (PDCCH) scrambled with a cell-radio network temporary identifier (C-RNTI) associated with the second cell.
45. The non-transitory computer-readable medium of claim 43 , wherein the executable instructions, when executed by the one or more processors, further cause the communications device to transmit the second message via a control resource set on the first cell.
46. The non-transitory computer-readable medium of claim 39 , wherein, to receive the report, the executable instructions, when executed by the one or more processors, further cause the communications device to receive the report that indicates the at least one preferred beam via a media access control-control element (MAC-CE).
47. The non-transitory computer-readable medium of claim 39 , wherein:
the report includes a beam index associated with the at least one preferred beam, and
to receive the report, the executable instructions, when executed by the one or more processors, further cause the communications device to receive the report via a media access control-control element (MAC-CE).
48. The non-transitory computer-readable medium of claim 39 , wherein:
the at least one preferred beam includes a plurality of preferred beams;
the report indicating the at least one preferred beam includes a plurality of beam indices associated with the plurality of preferred beams; and
the executable instructions, when executed by the one or more processors, further cause the communications device to receive the report that indicates the at least one preferred beam via a media access control-control element (MAC-CE).