An enhanced RLC STATUS PDU format is used in a wireless communication network in which a sender transmits AMD PDUs to a receiver, and the receiver responds a STATUS PDU. In the STATUS PDU, an ACK_SN field is provided for indicating the SN of a next not received AMD PDU which is not reported as missing in the STATUS PDU, and an E1 field is provided for indicating whether a set of NACK_SN, E1, and E2 fields follows or not. The NACK_SN field indicates a AMD PDU that has been detected as lost at the receiver. The E2 field indicates whether a set of SOstart, SOend, and E2 fields follows or not. The SOstart field indicates the first byte in the AMD PDU with SN=NACK_SN that has been detected as lost. The SOend field indicates the last byte in the AMD PDU with SN=NACK_SN that has been detected as lost.