a novel power - controlled random - access method allows a mobile station to gain fast access to the base station . at the mobile station , a composite power control command is devised after an initial access attempt . the determination of the composite command uses an open - loop power - control symbol and a closed - loop power - control symbol , to decide the action of the mobile station upon transmission of its next random - access signal . in the preferred embodiment , the composite power control command can specify different levels of increase or decrease in transmission power , and the composite power control command can specify a back - off by the mobile station . this composite power - control mechanism can help resolve collision between mobile stations accessing the same random access sub - channel and therefore maintain a low - delay in the random - access process and a high - utilization on the access - channel resource .