An uplink synchronization and access control system is provided, in which mobile stations transmit certain timing and access signals in dedicated intervals in an uplink stream. Access control is illustratively implemented as a two-stage process, in which a given mobile first transmits a generic uplink access signal, in one of the intervals. If this access is accepted, the base station transmits an access acknowledgment, which contains initial timing and power corrections, along with initial channel assignments, on which the mobile can initiate a call set-up process. For re-synchronization, mobiles transmit timing synchronization signals in the dedicated timing and access intervals. The base station measures the arrival time of the signals, and sends back appropriate timing corrections. The invention thereby ensures that orthogonality between mobiles is maintained.