A method of performing Pseudo-random-Noise (PN) quadrature covering for transmitting data via an access channel. The method according to one embodiment includes receiving a 42-bit access long code mask MIACMAC and a 42-bit access long code mask MQACMAC from an upper layer; generating an MI mask and an MQ mask for PN quadrature covering by using certain bits of an assigned channel number for the access channel; performing exclusive OR operations on certain bits of the received access long code mask MIACMAC; performing exclusive OR operations on certain bits of the received access long code mask MQACMAC; and transmitting signals via the access channel based on the generated 12-bit MI mask and the generated 12-bit MQ mask.