A wireless communication system is configured to monitor transmission sequence numbers (TSNs) assigned to protocol data units (PDUs) processed by the system. The system includes at least one user equipment (UE) having, a queue, and a Node B in communication with the UE. The UE determines that a data block having an expected TSN was not received, and generates a TSN status report message. The Node B retransmits a data block including the expected TSN to the UE in response to the TSN status report message. The retransmitted data block is placed in a specific location in the queue designated by the TSN status report message.