Apple Inc.
Contention Window Size Update for NR Systems Operating on Unlicensed Band

Abstract:

Systems and methods of adjusting contention window size (CWS) in a LBT procedure for both UL and DL unlicensed spectrum transmissions are described. The UE makes a HARQ-ACK determination for at least one code block group (CBG) of a transport block (TB) in a reference burst from a base station, determines whether the HARQ-ACK determination for the CBG meets a predetermined number of NACKs, transmits to the base station a single bit HARQ-ACK feedback for the TB that is dependent on whether the predetermined number of NACKs has been met, and receives or determines the adjusted CWS and uses the adjusted CWS for communication with the base station.