Supporting uplink transmissions

A wireless transmit receive unit (WTRU) comprising:

• a receiver;
• and
• a transmitter,
• wherein the receiver and the transmitter are configured to cause the WTRU to:
• receive signaling including information indicating a primary cell and at least one non-primary cell;
• receive a message with scheduling information indicating an allocation of uplink resources and a hybrid automatic repeat request (HARQ) process ID, wherein the WTRU has one or more HARQ processes;
• and
• transmit to at least the one non-primary cell an uplink transmission using a HARQ process indicated by the HARQ process ID and the allocation of uplink resources.

A base station comprising:

• a receiver;
• and
• a transmitter,
• wherein the receiver and the transmitter are configured to cause the base station to:
• transmit signaling including information indicating a primary cell and at least one non-primary cell;
• transmit a message with scheduling information indicating an allocation of uplink resources and a hybrid automatic repeat request (HARQ) process ID to a wireless transmit/receive unit (WTRU), wherein the WTRU has one or more HARQ processes;
• and
• receive an uplink transmission using a HARQ process indicated by the HARQ process ID and the allocation of uplink resources on at least the one non-primary cell.

A method performed by a base station, the method comprising:

• transmitting signaling including information indicating a primary cell and at least one non-primary cell;
• transmitting a message with scheduling information indicating an allocation of uplink resources and a hybrid automatic repeat request (HARQ) process ID to a wireless transmit/receive unit (WTRU), wherein the WTRU has one or more HARQ processes;
• and
• receiving an uplink transmission using a HARQ process indicated by the HARQ process ID and the allocation of uplink resources on at least the one non-primary cell.