1. A method of wireless communication, comprising:receiving a provisional grant uplink (UL) assignment at a user equipment (UE), wherein the provisional grant UL assignment identifies uplink resources for UL transmission by the UE;
performing a clear channel assessment (CCA) operation on a secondary component carrier (SCC) based on the provisional grant UL assignment, the SCC being a contention-based carrier;
transmitting a schedule request (SR), after receiving the provisional grant UL assignment, on the SCC when the CCA operation succeeds;
receiving a grant confirmation on the SCC in response to the SR; and
transmitting data on the SCC after receiving the grant confirmation.