1. A method for controlling transmissions on an uplink in a communication system, comprising: determining one or more characteristics of the communication system; partitioning available system resources into a plurality of channels; defining a plurality of back-off factors for the plurality of channels based at least in part on the one or more determined characteristics of the communication system, wherein each channel is associated with a respective back-off factor that identifies a reduction from peak transmit power level, and wherein each back-off factor ranges from zero to one; and assigning the plurality of channels to terminals for data transmission at power levels determined based at least in part on the plurality of back-off factors.