Improved timing synchronization and access control techniques for use in an orthogonal frequency division multiplexed (OFDM) wirelesssystem or other type of wireless communication system. In accordance with the invention, an uplink synchronization and access controlsystem 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 containing 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.
A netlist of a schematic diagram is generated. The netlist indicates the connectivity of components through connection lines. A normal display mode is provided in which at least a portion of the components are presented on the display, and connection lines corresponding to the components are also displayed. A topology display mode is provided in which the components are presented on the display without the connection lines. The user can switch between the topology display mode and the normal display mode while editing the schematic diagram. Automatic pin assignment and routing of the connection lines is performed according to the netlist, and is based upon grouping similarly classified connection lines. An abstract display mode is provided that presents abstract lines for a selected component, with a single abstract line running between two connected components. The abstract display mode is combinable with the topology display mode. Finally, the automatic positioning of components according to predefined topology templates is provided.