Listen before Talk and Channel Access Priority Class for PUCCH in New Radio Unlicensed

摘要

A method for determining Listen Before Talk (LBT) type and Channel Access Priority Class (CAPC) for Physical Uplink Control Channel (PUCCH) transmission in 5G New Radio-Unlicensed (NR-U) is proposed. Major uplink control information (UCI) transmitted over PUCCH are: (a) Scheduling Request (SR), (b) ACK/NAK (when no UL data to transmit), and (c) Channel State Information (CSI) Report (periodic). In one embodiment, UE selects Category 4 LBT for all PUCCH transmissions as Category 4 LBT offers fairness with other unlicensed network nodes. In another embodiment, UE selects either Category 4 LBT or Category 2 LBT or a mix of Category 2 and Category 4 for PUCCH transmission depending on the PUCCH format. In yet another embodiment, for Category 4 LBT, UE determines CAPC based on the associated UCI content.