Systems, methods, and instrumentalities are disclosed for uplink (UL) transmissions in wireless systems. The systems, methods and instrumentalities may include a wireless transmit/receive unit (WTRU) with a receiver configured to receive one or more uplink (UL) grants that may include allocations associated with a regular UL (RUL) carrier and a supplementary UL (SUL) carrier. The RUL and SUL carriers may be associated with a common downlink (DL) carrier of a serving cell. The WTRU may include a processor configured to select data from one or more logical channels for transmission in accordance with the allocations. The WTRU may include a transmitter configured to transmit data from one logical channel on the RUL carrier and to transmit data from another logical channel on the SUL carrier in accordance with the allocations.