Apple Inc.
APPARATUS AND METHOD OF HANDLING UPLINK LISTEN BEFORE TALK (LBT) FAILURES FOR NEW RADIO (NR) SYSTEMS OPERATING ON UNLICENSED SPECTRUM

Abstract:

Techniques are provided for determining and processing uplink listen before talk (LBT) failures, including the determination of a consistent and systematic LBT failure associated with uplink transmissions in new radio (NR) operating over unlicensed spectrum. For example, a user equipment (UE) identifies a plurality of transmission occasions to be performed by the UE over the unlicensed spectrum. The UE further performs a plurality of listen before talk (LBT) procedures associated with respective ones of the plurality of transmission occasions to be performed by the UE, and tracks a number of LBT failures during the performance of the plurality of LBT procedures, wherein a LBT failure occurs due to a channel used for the associated LBT procedure being busy or when an LBT backoff is still running from a previous LBT failure. The UE further implements a recovery procedure in response to the LBT failures exceeding a predetermined threshold within a predetermined time period.