A method for using orthogonal sub-channels (OSCs) in a wireless transmit/receive unit (WTRU). A capability report is received from the WTRU, including an indication whether the WTRU supports OSCs. A determination is made whether to use OSCs for the WTRU and the result of the determination is signaled to the WTRU. If OSCs are used with the WTRU, the signaling includes an OSC assignment for the WTRU. In one embodiment, two resources are assigned to the WTRU and each resource is assigned to a different OSC.