A method and device within a speech processing unit (SPU) for reducing scheduling delay between the SPU and a radio network node. Within the SPU, data packets are processed in a plurality of time slots that are subunits of frames. The device receives timing information from the node that identifies a beginning and an ending of processing periods in the node. The timing information is utilized to select a time slot within each frame as a target time slot. The target time slot has a position within each frame such that the scheduling delay between the ending of a processing period in the node and the beginning of the target time slot is minimized. Data packets for a particular channel are assigned to the target time slot to reduce the scheduling delay. The phase of the frame is then adjusted by erasing superfluous data packets.