In an embodiment, a wireless transmit/receive unit (WTRU) may include: at least one antenna; a transceiver operatively coupled to the at least one antenna; and a processor operatively coupled to the transceiver. The at least one antenna is configured to receive a first signal that includes a control message. The transceiver and the processor are configured to recover the control message from the first signal. The control message includes a resource allocation, a group identification and subframe pattern information. The transceiver and the processor are further configured to produce a second signal that includes data associated with group identification. The processor is further configured to have the transceiver and the at least one antenna transmit the second signal in resources assigned by the resource allocation and in subframes derived from the subframe pattern information. The transceiver and the at least one antenna are further configured to transmit the second signal.