The invention relates to a method and an arrangement for reducing transmission delay on a radio interface in a communication network, comprising a communication network node (15) transmitting packet data to one or more user equipments (18) over said radio interface. A number of transmission attempts needed for transmitting said packet data estimating, based on which a number of re-transmissions of said first packet data to perform is determined. The determined number of re-transmission is proactively transmitted before an ACK or NACK message is received from the user equipments.