Default PDSCH beam selection

Patent metadata

Field	Value
Publication number	US-11758547-B2
Application number	US-202017028714-A
Country	US
Kind code	B2
Filing date	Sep 22, 2020
Priority date	Oct 4, 2019
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A UE determines a default beam for a physical downlink shared channel (PDSCH) that is independent of a beam for a physical downlink control channel (PDCCH). The default PDSCH beam may be determined based on information received in a medium access control-control element (MAC-CE), or a radio resource control (RRC) message, a downlink control information (DCI). The default PDSCH beam may be determined based on at least one active transmission configuration indication (TCI) state for the PDSCH.

First claim

What is claimed is:

1. A method of wireless communication at a user equipment (UE), comprising:
transmitting an indication of a capability to determine a default beam for physical downlink shared channel (PDSCH) that is independent of a beam for a control resource set (CORESET) for a physical downlink control channel (PDCCH);
determining the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH, based on information received in a medium access control-control element (MAC-CE), a radio resource control (RRC) message, a downlink control information (DCI), or a message activating at least one transmission configuration indication (TCI) state for the PDSCH; and
using the default beam based on the information received in the MAC-CE, the RRC message, the DCI, or the message activating the at least one TCI state to receive the PDSCH from a base station in response to a determination that a scheduling offset between the PDSCH and a scheduling DCI that schedules the PDSCH is less than a threshold.

2. The method of claim 1 , wherein the UE receives the information in the MAC-CE and determines the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH based on the information received in the MAC-CE.

3. The method of claim 2 , wherein the MAC-CE activates a PDSCH TCI state, and the UE determines the default beam for the PDSCH based on the PDSCH TCI state indicated in the MAC-CE.

4. The method of claim 1 , wherein the UE receives the information in the RRC message and determines the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH based on the information received in the RRC message.

5. The method of claim 1 , wherein the UE receives the information in the DCI and determines the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH based on the information received in the DCI.

6. The method of claim 1 , wherein the UE receives the information in the message activating the at least one TCI state for the PDSCH and determines the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH based on an activated TCI state for the PDSCH having a lowest index.

7. The method of claim 1 , wherein if the UE does not receive the information, the UE determines the default beam for the PDSCH based on a fallback rule.

8. The method of claim 7 , wherein the fallback rule includes:
determining the default beam for the PDSCH based on a quasi co-location (QCL) relationship to a configured CORESET having a lowest CORESET identifier (ID), if one or more CORESETs are configured for the UE; or
determining the default beam for the PDSCH based on an activated PDSCH TCI state having a lowest TCI state ID.

9. The method of claim 1 , wherein if the UE has not received an activation of a PDSCH TCI state, the UE determines the default beam for the PDSCH based on a quasi co-location (QCL) relationship to a configured CORESET having a lowest CORESET identifier (ID), if one or more CORESETs are configured for the UE.

10. The method of claim 1 , further comprising:
receiving an indicator from the base station indicating for the UE to determine the default beam for the PDSCH independent of the beam for the CORESET for the PDCCH.

11. The method of claim 10 , wherein the indicator is received in radio resource control (RRC) signaling from the base station.

12. The method of claim 1 , wherein the UE determines the default beam for the PDSCH that is independent of the beam for the CORESET having a lowest identifier (ID) in response to the information received in the MAC-CE, the RRC message, the DCI, or the message activating at least one TCI state for the PDSCH.

13. An apparatus for wireless communication at a user equipment (UE), comprising:
memory; and
at least one processor coupled to the memory and configured to:
transmit an indication of a capability to determine a default beam for physical downlink shared channel (PDSCH) that is independent of a beam for a control resource set (CORESET) for a physical downlink control channel (PDCCH);
determine the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH, based on information received in a medium access control-control element (MAC-CE), a radio resource control (RRC) message, a downlink control information (DCI), or a message activating at least one transmission configuration indication (TCI) state for the PDSCH; and
use the default beam based on the information received in the MAC-CE, the RRC message, the DCI, or the message activating the at least one TCI state to receive the PDSCH from a base station in response to a determination that a scheduling offset between the PDSCH and a scheduling DCI that schedules the PDSCH is less than a threshold.

14. The apparatus of claim 13 , wherein the at least one processor is configured to receive the information in the MAC-CE and determine the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH based on the information received in the MAC-CE.

15. The apparatus of claim 13 , wherein the at least one processor is configured to receive the information in the RRC message and determine the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH based on the information received in the RRC message.

16. The apparatus of claim 13 , wherein the at least one processor is configured to receive the information in the DCI and determine the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH based on the information received in the DCI.

17. The apparatus of claim 13 , wherein the at least one processor is configured to receive the information in the message activating the at least one TCI state for the PDSCH and determine the default beam for the PDSCH that is independent of the beam for the CORESET for the PDCCH based on an activated TCI state for the PDSCH having a lowest index.

18. The apparatus of claim 13 , wherein if the apparatus does not receive the information, the at least one processor is configured to determine the default beam for the PDSCH based on a fallback rule that includes determining the default beam for the PDSCH based on a quasi co-location (QCL) relationship to a configured CORESET having a lowest CORESET identifier (ID), if one or more CORESETs are configured for the UE, or determining the default beam for the PDSCH based on an activated PDSCH TCI state having a lowest TCI state ID.

19. The apparatus of claim 13 , wherein the at least one processor is further configured to:
receive an indicator from the base station indicating for the UE to determine the default beam for the PDSCH independent of the beam for the CORESET for the PDCCH.

20. The apparatus of claim 13 , wherein the at least one processor is configured to determine the default beam for the PDSCH that is independent of the beam for the CORESET having a lowest identifier (ID) in response to the information received in the MAC-CE, the RRC message, the DCI, or the message activating at least one TCI state for the PDSCH.

21. A method of wireless communication at a base station, comprising:
receiving, from a user equipment (UE), an indication of a capability to determine a default beam for a physical downlink shared channel (PDSCH) that is independent of a beam for a control resource set (CORESET) for a physical downlink control channel (PDCCH);
transmitting information to t

Assignees

• Qualcomm Inc

Inventors

• Zhou Yan
• Luo Tao
• He Ruhua
• Challa Raghu Narayan
• Li Yong
• Cheraghi Parisa
• Gaal Peter
• Montojo Juan
• Manolakos Alexandros
• Gorokhov Alexei Yurievitch

Classifications

• H04B7/088 Primary

  using beam selection · CPC title

• H04W72/23 Primary

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04L5/0023

  Time-frequency-space · CPC title

• H04L5/0044

  Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH · CPC title

• H04L5/0053

  Allocation of signalling, i.e. of overhead other than pilot signals · CPC title