A transmitting peer transmits radio blocks over a radio interface from within a transmit window. A receiving peer receives the radio blocks within a receive window, and in case of a not correctly received radio block, sending back a NACK (Not Acknowledged) signaling message to inform the transmitting peer of reception failure. Upon reception of the NACK signaling message, the transmitting peer retransmits, until expiration of the transmit window, the not correctly received RLC/MAC radio block. The radio blocks are re-assembling in sequence at the receiving peer. Each radio block is considered as being permanently lost if not correctly received within the receive window. All correctly received radio blocks are delivered to a higher protocol layer. The network transmits a notification message to both the transmitting peer and the receiving peer to select a size of the transmit and receive windows inside a range of predetermined values including values less than 64 radio blocks.