BEAM RECOVERY WITHOUT BEAM CORRESPONDENCE

• US 20200136895A1
• Filed: 10/10/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: VENUGOPAL, Kiran, JOHN WILSON, Makesh Pravin, BAI, Tianyang, RYU, Jung Ho, ZHANG, Xiaoxia, LUO, Tao
• Application Number:
  US16/598,946
• Publication Number:
  US 20200136895A1
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04L 41/0668 by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 76/19 Connection re-establishment

Abstract

Disclosed are techniques for beam failure recovery in a wireless communications system. In an aspect, a user equipment (UE) detects a beam failure of a first downlink beam received at the UE from a base station, sends, to the base station, a random access channel (RACH) request identifying one or more candidate downlink beams received at the UE from the base station, and, in response to sending the RACH request, receives, from the base station, a response to the RACH request, the response identifying a second downlink beam from the one or more candidate downlink beams to replace the first downlink beam and indicating a type of beam recovery associated with the second downlink beam for which downlink beam resources have been reserved.

Claims

1. A method of beam failure recovery in a wireless communications system, comprising:

detecting, by a user equipment (UE), a beam failure of a first downlink beam received at the UE from a base station;

sending, by the UE to the base station, a random access channel (RACH) request identifying one or more candidate downlink beams received at the UE from the base station; and

receiving, at the UE from the base station, a response to the RACH request, the response identifying a second downlink beam from the one or more candidate downlink beams to replace the first downlink beam and indicating a type of beam recovery associated with the second downlink beam for which the base station has reserved downlink beam resources.

2. The method of claim 1, wherein the type of beam recovery is indicated by an identification of a different control resource set (CORESET) for each of a primary cell (PCell) recovery, a secondary cell (SCell) recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

3. The method of claim 1, wherein the type of beam recovery is indicated by an identification of the same CORESET scrambled with a different radio network temporary identifier (RNTI) for each of a PCell recovery, a SCell recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

4. The method of claim 1, wherein the type of beam recovery is indicated by the same CORESET, the same downlink control information (DCI), and different additional bits to distinguish each of a PCell recovery, a SCell recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

5. The method of claim 1, wherein the first downlink beam is a downlink transmission beam for an SCell supported by the base station.

6. The method of claim 5, wherein the first downlink beam uses a millimeter wave (mmW) frequency band to transmit periodic reference signals.

7. The method of claim 1, wherein the first downlink beam is a downlink transmission beam for a PCell supported by the base station.

8. The method of claim 7, wherein the first downlink beam uses a mmW frequency band to transmit periodic reference signals.

9. The method of claim 1, further comprising:

receiving, at the UE from the base station, a physical downlink control channel (PDCCH) order;

performing, by the UE, a RACH procedure in response to the PDCCH order, wherein the RACH procedure includes sending the RACH request and receiving the response to the RACH request; and

determining, by the UE, an uplink transmit beam based on the RACH procedure.

10. The method of claim 9, wherein the uplink transmit beam is associated with a SCell supported by the base station.

11. The method of claim 9, wherein the uplink transmit beam is associated with a PCell supported by the base station.

12. A method of beam failure recovery in a wireless communications system, comprising:

receiving, at a base station from a user equipment (UE), a random access channel (RACH) request identifying one or more candidate downlink beams received at the UE from the base station; and

sending, from the base station to the UE, a response to the RACH request, the response identifying a second downlink beam from the one or more candidate downlink beams to replace a first downlink beam and indicating a type of beam recovery associated with the second downlink beam for which downlink beam resources have been reserved.

13. The method of claim 12, further comprising:

receiving, at the base station, a message from the UE indicating that a beam failure has occurred at the UE.

14. The method of claim 13, wherein the message from the UE indicating that the beam failure has occurred comprises a scheduling request (SR).

15. The method of claim 12, wherein the type of beam recovery is indicated by an identification of a different control resource set (CORESET) for each of a primary cell (PCell) recovery, a secondary cell (SCell) recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

16. The method of claim 15, wherein the base station reserves a different CORESET for each of the PCell recovery, the SCell recovery, the uplink transmit beam associated with the PCell, and the uplink transmit beam associated with the SCell.

17. The method of claim 12, wherein the type of beam recovery is indicated by an identification of the same CORESET scrambled with a different radio network temporary identifier (RNTI) for each of a PCell recovery, a SCell recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

18. The method of claim 17, wherein the base station reserves the same CORESET for each of the PCell recovery, the SCell recovery, the uplink transmit beam associated with the PCell, and the uplink transmit beam associated with the SCell.

19. The method of claim 12, wherein the type of beam recovery is indicated by the same CORESET, the same downlink control information (DCI), and different additional bits to distinguish each of a PCell recovery, a SCell recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

20. The method of claim 19, wherein the base station reserves the same CORESET for each of the PCell recovery, the SCell recovery, the uplink transmit beam associated with the PCell, and the uplink transmit beam associated with the SCell.

21. The method of claim 12, wherein the first downlink beam is a downlink transmission beam for an SCell supported by the base station.

22. The method of claim 12, wherein the base station transmits periodic reference signals on the first downlink beam, and wherein the first downlink beam operates on a millimeter wave (mmW) frequency band.

23. The method of claim 12, wherein the first downlink beam is a downlink transmission beam for a PCell supported by the base station.

24. The method of claim 12, further comprising:

sending, by the base station to the UE, a physical downlink control channel (PDCCH) order; and

performing, by the base station, a RACH procedure after sending the PDCCH order, wherein the RACH procedure includes receiving the RACH request and sending the response to the RACH request, and wherein the UE determines an uplink transmit beam based on the RACH procedure.

25. The method of claim 12, wherein the uplink transmit beam is associated with a SCell supported by the base station, or

wherein the uplink transmit beam is associated with a PCell supported by the base station.

26. An apparatus for beam failure recovery in a wireless communications system, comprising:

at least one processor of a user equipment (UE) configured to;

detect a beam failure of a first downlink beam received at the UE from a base station;

send, to the base station, a random access channel (RACH) request identifying one or more candidate downlink beams received at the UE from the base station; and

receive, from the base station, in response to the RACH request being sent, a response to the RACH request, the response identifying a second downlink beam from the one or more candidate downlink beams to replace the first downlink beam and indicating a type of beam recovery associated with the second downlink beam for which downlink beam resources have been reserved.

27. The apparatus of claim 26, wherein the type of beam recovery is indicated by an identification of a different control resource set (CORESET) for each of a primary cell (PCell) recovery, a secondary cell (SCell) recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

28. The apparatus of claim 26, wherein the type of beam recovery is indicated by an identification of the same CORESET scrambled with a different radio network temporary identifier (RNTI) for each of a PCell recovery, a SCell recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

29. The apparatus of claim 26, wherein the type of beam recovery is indicated by the same CORESET, the same downlink control information (DCI), and different additional bits to distinguish each of a PCell recovery, a SCell recovery, an uplink transmit beam associated with the PCell, and an uplink transmit beam associated with the SCell.

30. An apparatus for beam failure recovery in a wireless communications system, comprising:

at least one processor of a base station serving a user equipment (UE) and configured to;

receive, from the UE, a random access channel (RACH) request identifying one or more candidate downlink beams received at the UE from the base station; and

send, to the UE, in response to reception of the RACH request, a response to the RACH request, the response identifying a second downlink beam from the one or more candidate downlink beams to replace the first downlink beam and indicating a type of beam recovery associated with the second downlink beam for which downlink beam resources have been reserved.