An apparatus and method for minimizing a non-transmittable period where high-speed packet data transmission is impossible. In the apparatus, a non-transmittable period calculator receives transmission gap-related information for a UE from a radio network controller, calculates a transmission gap starting point based on the transmission gap-related information, defines a period determined by excluding the downlink transmission period from the transmission gap starting point as the non-transmittable period, and suspends transmission of the high-speed packet data to the UE for the non-transmittable period. A scheduler performs scheduling on the high-speed packet data under the control of the non-transmittable period calculator so that transmission of the high-speed packet data to the UE is suspended for the downlink transmission period.