Search

US-12628162-B2 - Default downlink or uplink beam for downlink control channel with repetition configuration

US12628162B2US 12628162 B2US12628162 B2US 12628162B2US-12628162-B2

Abstract

In a wireless network, a physical downlink control channel (PDCCH) may be transmitted in multiple repetitions, which may cause ambiguity in cases where a user equipment (UE) has to determine a default downlink or uplink beam to receive or transmit a data channel. Accordingly, in cases where a UE receives a PDCCH associated with a repetition configuration and the PDCCH does not include a beam indication, the UE may determine a default beam to receive or transmit a data channel scheduled by the PDCCH based on the repetition configuration of the PDCCH. For example, the PDCCH may be associated with multiple control resource sets (CORESETs) and/or a CORESET associated with multiple transmission configuration indication (TCI) states. Accordingly, the UE may determine the default beam based on one or more parameters associated with the multiple CORESETs and/or the multiple TCIs associated with a CORESET.

Inventors

  • Fang Yuan
  • Yan Zhou
  • Mostafa Khoshnevisan
  • Tao Luo

Assignees

  • QUALCOMM INCORPORATED

Dates

Publication Date
20260512
Application Date
20201221

Claims (20)

  1. 1 . A method of wireless communication performed by a user equipment (UE), comprising: receiving, from a base station, downlink control information (DCI) scheduling a downlink data channel without a transmission configuration indication (TCI) field, wherein the DCI is associated with a repetition configuration of a physical downlink control channel (PDCCH), the repetition configuration indicating whether the PDCCH is associated with multiple control resource sets (CORESETs) or multiple TCI states associated with a CORESET; determining a default beam for the downlink data channel based at least in part on the repetition configuration, wherein the default beam is determined based at least in part on one of the multiple CORESETs or one or a plurality of the multiple TCI states associated with the CORESET, wherein either one or the plurality of the multiple TCI states that are used in determining the default beam based at least in part on whether the downlink data channel is associated with a single frequency network (SFN) repetition configuration; and receiving the downlink data channel using the default beam.
  2. 2 . The method of claim 1 , wherein the downlink data channel is associated with a single reception occasion, and wherein the repetition configuration associated with the DCI includes the multiple CORESETs.
  3. 3 . The method of claim 2 , wherein the default beam is associated with a TCI state or a quasi co-location assumption applied for one of the multiple CORESETs having a lowest CORESET identifier.
  4. 4 . The method of claim 2 , wherein the default beam is associated with a TCI state or a quasi co-location assumption applied for one of the multiple CORESETs associated with a search space having a lowest search space identifier or one of the multiple CORESETs associated with a search space having a highest search space identifier.
  5. 5 . The method of claim 2 , wherein the default beam is associated with a TCI state or a quasi co-location assumption applied for one of the multiple CORESETs associated with a monitored search space that is latest in time or one of the multiple CORESETs associated with a monitored search space that is earliest in time.
  6. 6 . The method of claim 2 , wherein the default beam is associated with a first TCI state and a second TCI state that are respectively associated with a first CORESET and a second CORESET, of the multiple CORESETs, based at least in part on the downlink data channel having a single frequency network configuration.
  7. 7 . The method of claim 1 , wherein the downlink data channel is associated with a single reception occasion, and wherein the repetition configuration associated with the DCI includes the CORESET associated with the multiple TCI states.
  8. 8 . The method of claim 7 , wherein the default beam is associated with a first TCI state, of the multiple TCI states associated with the CORESET.
  9. 9 . The method of claim 7 , wherein the default beam is associated with a lowest TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET.
  10. 10 . The method of claim 7 , wherein the default beam is associated with a TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET, that is quasi co-located with a synchronization signal block having a lowest index.
  11. 11 . The method of claim 7 , wherein the default beam is associated with a first TCI state and a second TCI state, of the multiple TCI states associated with the CORESET, based at least in part on the downlink data channel having a single frequency network configuration.
  12. 12 . The method of claim 1 , wherein the downlink data channel is configured with multiple reception occasions, and wherein the repetition configuration associated with the DCI includes the multiple CORESETs.
  13. 13 . The method of claim 12 , wherein the multiple reception occasions include: a first set of reception occasions in which the default beam is associated with one of the multiple CORESETs having a lowest CORESET identifier, and a second set of reception occasions in which the default beam is associated with one of the multiple CORESETs having a highest CORESET identifier.
  14. 14 . The method of claim 12 , wherein the multiple reception occasions include: a first set of reception occasions in which the default beam is associated with one of the multiple CORESETs associated with a search space having a lowest search space identifier, and a second set of reception occasions in which the default beam is associated with one of the multiple CORESETs associated with a search space having a highest search space identifier.
  15. 15 . The method of claim 12 , wherein the multiple reception occasions include: a first set of reception occasions in which the default beam is associated with one of the multiple CORESETs associated with a monitored search space that is latest in time, and a second set of reception occasions in which the default beam is associated with one of the multiple CORESETs associated with a monitored search space that is earliest in time.
  16. 16 . The method of claim 12 , wherein the multiple reception occasions include at least a first set of reception occasions and a second set of reception occasions associated with a cyclic mapping, a sequential mapping, a demodulation reference signal (DMRS) code division multiplexing group index, or frequency allocation parts.
  17. 17 . The method of claim 1 , wherein the downlink data channel is configured with multiple reception occasions, and wherein the repetition configuration associated with the DCI includes the CORESET associated with the multiple TCI states.
  18. 18 . The method of claim 17 , wherein the multiple reception occasions include: a first set of reception occasions in which the default beam is associated with a first TCI state, of the multiple TCI states associated with the CORESET, and a second set of reception occasions in which the default beam is associated with a second TCI state, of the multiple TCI states associated with the CORESET.
  19. 19 . The method of claim 17 , wherein the multiple reception occasions include: a first set of reception occasions in which the default beam is associated with a lowest TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET, and a second set of reception occasions in which the default beam is associated with a highest TCI identifier, of the TCI identifiers associated with the multiple TCI states associated with the CORESET.
  20. 20 . The method of claim 17 , wherein the multiple reception occasions include: a first set of reception occasions in which the default beam is associated with a first TCI identifier, of TCI identifiers associated with the multiple TCI states associated with the CORESET, that is quasi co-located (QCLed) with a synchronization signal block (SSB) having a lowest index, and a second set of reception occasions in which the default beam is associated with a second TCI identifier, of the TCI identifiers associated with the multiple TCI states associated with the CORESET, that is QCLed with an SSB having a highest index.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a 371 national stage of PCT Application No. PCT/CN2020/137889, filed on Dec. 21, 2020, entitled “DEFAULT DOWNLINK OR UPLINK BEAM FOR DOWNLINK CONTROL CHANNEL WITH REPETITION CONFIGURATION,” which is hereby expressly incorporated by reference herein. FIELD OF THE DISCLOSURE Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for determining a default downlink or uplink beam for a downlink control channel with a repetition configuration. BACKGROUND Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, or the like). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, single-carrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP). A wireless network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs). A UE may communicate with a BS via the downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a 5G BS, a 5G Node B, or the like. The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless communication devices to communicate on a municipal, national, regional, and even global level. 5G, which may also be referred to as New Radio (NR), is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). 5G is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDM with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE and 5G technologies. Preferably, these improvements should be applicable to other multiple access technologies and the telecommunication standards that employ these technologies. SUMMARY In a wireless network, a base station may transmit a physical downlink control channel (PDCCH) with multiple repetitions to improve reliability and/or robustness. For example, one PDCCH repetition technique may be to transmit one downlink control information (DCI) message in two search spaces that are associated with two control resource sets (CORESETs). In another PDCCH repetition technique, one DCI message may be transmitted in one CORESET associated with two transmission configuration indication (TCI) states (e.g., using two beams pointing in different directions). However, the PDCCH repetition may create ambiguity in cases where the UE has to determine a default downlink or uplink beam to receive or transmit a data channel (e.g., a physical downlink shared channel (PDSCH) or a physical uplink shared channel (PUSCH)) scheduled by the DCI message (e.g., because the DCI message does not have a TCI field). For example, when a UE receives a DCI without a TCI field in a wireless network that does not support PDCCH repetition, the UE generally determines a default beam to receive a PDSCH or transmit a PUSCH scheduled by the DCI based on a TCI state, a quasi co-location (QCL) assumption, a search space, and/or another suitable parameter associated with a CORESET used to transmit the PDCCH. Accordingly, when the PDCCH is associated with multiple CORESETs and/or one or more CORESETs that are associated with multiple TCI states, the UE may be unable to determine a beam to use to receive a PDSCH or transmit a PUSCH scheduled by the DCI in cases where the PDCCH does not indicate a downlink or uplink beam.