Abstract: A method and apparatus for controlling by a mobile terminal a rate of packet data transmitted in a reverse direction from the mobile terminal to base station in a mobile communication system. The method and apparatus comprise determining a transmission signal-to-noise ratio of a signal on a forward channel transmitted from the base station, and selecting one transition probability set from predetermined transition probability sets according to a value of the signal-to-noise ratio; selecting one transition probability from the selected transition probability set according to reverse rate control information received from the base station, and changing the transmission rate according to the selected transition probability.