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EP-3963922-B1 - TRIGGERING RECOVERY PROCEDURES BASED ON LISTEN-BEFORE-TALK (LBT) METRICS

EP3963922B1EP 3963922 B1EP3963922 B1EP 3963922B1EP-3963922-B1

Inventors

  • DEOGUN, Pravjyot Singh
  • BHATTAD, KAPIL
  • OZTURK, OZCAN
  • ZHANG, XIAOXIA
  • SUN, JING
  • THYAGARAJAN, ANANTA NARAYANAN

Dates

Publication Date
20260506
Application Date
20200313

Claims (15)

  1. A method (400) of wireless communication performed by an apparatus of a user equipment, UE (120), comprising: performing (305, 410) a set of listen-before-talk, LBT, procedures to access an unlicensed spectrum; determining (310, 420) an LBT metric associated with a result of the set of LBT procedures wherein the LBT metric is an LBT failure metric; and characterized by selectively triggering (320, 430) a recovery procedure based on the LBT metric satisfying an LBT metric threshold, wherein the LBT metric relates to a first bandwidth part, and wherein selectively triggering the recovery procedure comprises: performing a bandwidth part switch from the first bandwidth part to a second bandwidth part; transmitting, to a serving cell (110), a reporting message indicating triggering of the bandwidth part switch, wherein the reporting message is at least one of a radio resource control, RRC, message, a medium access control, MAC, message, or a physical layer message, wherein the reporting message further includes information indicating that the LBT metric satisfies the LBT metric threshold.
  2. The method of claim 1, wherein the LBT metric is at least one of: a metric relating to a quantity of LBT failures, a metric relating to a channel busy state as a result of LBT failure, or a metric relating to an amount of data missed as a result of LBT failure.
  3. The method of claim 1, further comprising resetting the LBT metric based on at least one of a reconfiguration of the LBT metric or a reconfiguration of a timer associated with the LBT metric.
  4. The method of claim 1, wherein the second bandwidth part is different from an initial access bandwidth part or a default bandwidth part.
  5. The method of claim 1, wherein the reporting message further includes information identifying a bandwidth part switch triggering event.
  6. The method of claim 1, wherein: the reporting message is transmitted to the serving cell after the bandwidth part switch, and wherein the reporting message a random access channel, RACH, message.
  7. The method of claim 1, wherein determining the LBT metric comprises: determining that an LBT failure occurs for an LBT procedure of the set of LBT procedures based on a failure to transmit on an uplink transmission instance, and, wherein the uplink transmission instance is at least one of: a physical uplink shared channel, PUSCH, transmission, a physical uplink control channel, PUCCH, transmission, or a physical random access channel, PRACH, transmission, or a sounding reference signal, SRS, transmission.
  8. The method of claim 1, wherein: the LBT metric is incremented for each failure to transmit on an uplink transmission instance, or the LBT metric is incremented based on whether at least one failure to transmit on an uplink transmission instance occurs during a threshold period of time, or the LBT metric is incremented based on a threshold quantity of uplink transmission failures occurring during a threshold period of time.
  9. The method of claim 1, wherein a threshold period of time associated with identifying an LBT failure associated with the LBT metric is ended and the LBT failure is not determined based on a threshold quantity of successful uplink transmissions occurring during the threshold period of time.
  10. The method of claim 1, wherein the LBT metric is at least one of: an absolute metric representing at least one LBT failure in a measurement interval, a ratio metric representing a ratio of LBT failures to occasions during which an LBT failure can occur in the measurement interval, an absolute metric representing a threshold quantity of LBT failures occurring in the measurement interval, or an absolute metric representing a quantity of LBT failures occurring in the measurement interval, and wherein the measurement interval is at least one of: a set of slots, a set of mini-slots, a set of occasions in a single slot, or a set of uplink grants in a channel occupancy time or uplink burst.
  11. A method (500) of wireless communication performed by an apparatus of a base station, BS (110), comprising: configuring (510), for a user equipment, UE, (120) on a first bandwidth part, a second bandwidth part to enable a bandwidth part switch for the UE and in connection with a listen-before-talk, LBT, metric, characterized in that wherein the LBT metric is an LBT failure metric and in that the second bandwidth part is different from an initial access bandwidth part or a default bandwidth part; and characterized by receiving (520) a reporting message indicating that the LBT metric satisfies a threshold and indicating a trigger of the bandwidth part switch by the UE after the LBT metric satisfies a threshold, wherein the reporting message further includes information indicating that the LBT metric satisfies the LBT metric threshold and wherein the reporting message is at least one of a radio resource control, RRC, message, a medium access control, MAC, message, or a physical layer message.
  12. The method of claim 11, wherein the reporting message includes information identifying at least one of: a bandwidth part switch triggering event, or a quantity of LBT failures.
  13. The method of claim 11, further comprising: receiving a random access channel, RACH, message after the bandwidth part switch.
  14. An apparatus for wireless communication at a user equipment, UE (120), comprising means for carrying out the method of any one of claims 1 to 10.
  15. An apparatus for wireless communication at a base station, BS (110), comprising means for carrying out the method of any one of claims 11 to 13.

Description

TECHNICAL FIELD Aspects of the present disclosure relate generally to wireless communication and more particularly to techniques for channel congestion measurement. DESCRIPTION OF THE RELATED TECHNOLOGY 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 (for example, bandwidth, transmit power, etc.). 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 communication network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs). A user equipment (UE) may communicate with a base station (BS) via the downlink (DL) and uplink (UL). The DL (or forward link) refers to the communication link from the BS to the UE, and the UL (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 NodeB, an LTE evolved nodeB (eNB), a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a New Radio (NR) BS, or a 5G NodeB. The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different UEs to communicate on a municipal, national, regional, and even global level. NR, which also may be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). NR 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 DL, using CP-OFDM or SC-FDM (for example, also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the UL (or a combination thereof), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. SAMSUNG: "UL LBT problem detection", 3GPP DRAFT; R2-1903261, vol. RAN WG2, no. Xi'an, China; 29 March 2019, XP051692535, relates to how to detect the UL LBT problems in NR-U operations. HUAWEI ET AL: "Email discussion report on [105#49][NR] LBT impacts in MAC", 3GPP DRAFT; R2-1904114, vol. RAN WG2, no. Xi'an, China 6 April 2019, XP051701428, is an email discussion that relates to LBT impacts to MAC with an Intended outcome: Report, clarify agreements from SI, identify tentative "easy" agreements, and questions to be resolved. SUMMARY The present invention defines a method of wireless communication performed by an apparatus of a user equipment, UE, according to independent claim 1, a corresponding method of wireless communication performed by an apparatus of a base station, BS, according to independent claim 11, a corresponding apparatus for wireless communication at a user equipment, UE, according to independent claim 14 and a corresponding apparatus for wireless communication at a base station, BS, according to independent claim 14. Preferred embodiments are defined in the dependent claims. The systems, methods and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein. One innovative aspect of the subject matter described in this disclosure can be implemented in a method of wireless communication performed by an apparatus of a user equipment (UE). The method may include performing a set of listen-before-talk (LBT) procedures to access an unlicensed spectrum; determining an LBT metric associated with a result of the set of LBT procedures; and selectively triggering a recovery procedure based on the LBT metric satisfying an LBT metric threshold. In some aspects, selectively triggering the recovery procedure includes at least one of triggering one or more a radio link failure (RLF) related procedures, performing a recovery action, or reporting the LBT metric to a base station (BS). In some aspects, the LBT metric is an LBT failure metric. In some aspects, determining the LBT metric includes determining that an LBT failure occurs for an LBT procedure of the set of LBT procedures based on a failure to transmit on an uplin