A system is proposed to provide DRX/DTX configuration for mixed real time and non-real time transmission scenarios in a mobile telecommunications environment, particularly applicable to 3GPP networks. The proposed DRX/DTX configuration involves maintaining the DRX/DTX interval the same between the switching of real time VoIP data from an active period to a silence period. The proposed DRX/DTX configuration schedules transmission and/or reception times for a mobile device so that packets for non-real time services are transmitted/received immediately after packets for real time services.