A method and wireless communication system for providing channel
assignment information used to support an uplink (UL) channel and a
downlink (DL) channel. The system includes at least one Node-B and at
least one wireless transmit/receive unit (WTRU). The WTRU communicates
with the Node-B via a common control channel, the UL channel and the DL
channel. The WTRU receives a message from the Node-B via the common
control channel. The message includes an indication of whether the
message is intended for assigning radio resources to the UL channel or
the DL channel. The WTRU determines whether the message is intended for
the WTRU and, if so, the WTRU determines whether the message is for
assigning radio resources to the UL channel or the DL channel. The WTRU
takes an appropriate action based on whether the message is for assigning
radio resources to the UL channel or the DL channel.