A method and wireless transmit/receive unit (WTRU) for transmitting data over an enhanced uplink (EU) channel is disclosed. The WTRU receives a scheduled grant and at least one non-scheduled grant. The WTRU transmits a medium access control for EU channel (MAC-e) protocol data unit (PDU) over an EU channel. The MAC-e PDU includes multiplexed data. The multiplexed data includes scheduled data. An amount of the multiplexed data is not greater than a size of a largest supported EU transport format combination (E-TFC) size that does not exceed a size based on the received scheduled grant, the received at least one non-scheduled grant, and a power offset. The MAC-e PDU is transmitted based on a selected E-TFC. The selected E-TFC is a smallest E-TFC that supports the multiplexed data of the MAC-e PDU.