In a method of transmitting control signals for uplink transmission of packet data, a control channel carrying control signal data that is shared by a plurality of users is transmitted in the downlink to the users. The shared control channel includes fields identifiable by, or specified for, different ones of the users, so that each field includes control signal data for a specified user for uplink transmission of packet data. The specified user decodes a corresponding field of the shared control channel to interpret the control signal data, and may transmit packet data in the uplink in accordance with the decoded control signal data.