A communication system includes a plurality of access terminals, and an access network. The access network schedules a transmission of data in a time interval from one of the access terminals. The access network selects a multiple access transmission mode from a plurality of multiple access transmission modes, and broadcasts the selected multiple access transmission mode to the access terminals. The selected mode may include a mode in which data is code-division-multiplexed during the time interval, and modes in which data is code-division-multiplexed during a first portion of the time interval, and data is either time-division-multiplexed or orthogonal-frequency-division-multiplexed during a second portion of the time interval.