Systems and techniques for scheduling of data transmission to remote mobile units so as to provide at least an acceptably low level of delay. A scheduler computes an urgency value for each data stream serving a mobile unit and sets the urgency value equal to the highest urgency value of a data stream serving the mobile unit. The scheduler computes a scheduling priority for each mobile unit based on a computation that takes into account the urgency value of the mobile unit and schedules the highest priority mobile unit for service, selecting the highest priority data stream serving the mobile unit scheduled for transmission. The urgency value for a data stream depends on the sensitivity of the data stream to delay and the delay experienced by the data stream. Computation of the urgency value may take into account a delay limit associated with the data stream.