Devices and methods for ELAA multi-carrier LBT

An apparatus of a user equipment for uplink channel access in license-assisted access (LAA), the apparatus comprising:

• a memory;
• and
• processing circuitry coupled to the memory and configured to:
• process one or more uplink (UL) grants from a base station scheduling a plurality of physical uplink shared channel (PUSCH) transmissions on a plurality of unlicensed carriers at a first PUSCH starting position, the one or more UL grants indicating a first channel access procedure for the plurality of PUSCH transmissions, wherein the first PUSCH starting position is identified based on a grant timing association included in the one or more UL grants;
• select a first unlicensed carrier of the plurality of unlicensed carriers for the first channel access procedure associated with the first PUSCH starting position, wherein the plurality of unlicensed carriers are identified in the one or more UL grants;
• and
• select at least a second unlicensed carrier of the plurality of unlicensed carriers other than the first unlicensed carrier for a second channel access procedure associated with the first PUSCH starting position.