METHOD AND APPARATUS OF CONTROL SIGNALING IN UNLICENSED SPECTRUM

Methods and apparatuses for control signaling for an unlicensed spectrum band. A method of a user equipment (UE) in a wireless communication system includes receiving, from a base station (BS), a downlink control information (DCI) format and determining a type of channel access procedure based on a field in the DCI format. The type of channel access procedure is one of: a first type of channel access procedure that includes a random time duration for sensing; a second type of channel access procedure that includes a positive and deterministic time duration for sensing; or a third type of channel access procedure that does not include a time duration for sensing. The method further includes performing a channel access procedure based on the determined type of channel access procedure and transmitting an uplink transmission on a channel with shared spectrum channel access after performing the channel access procedure.