An apparatus and method for simultaneously receiving a plurality of Packet Data Units (PDUs) are provided. In a method of receiving a plurality of PDUs, the plurality of PDUs, each PDU having an associated Sequence Number (SN), are received, one of the plurality of PDUs is input into a reception buffer, a first variable is updated based on the SN of the PDU input into the reception buffer, wherein the first variable indicates the highest SN of PDUs input into the reception buffer, a determination is made if a timer is running, if the timer is not running, a determination is made if all of the received PDUs are input into the reception buffer, and, if any of the received PDUs is not input into the reception buffer, a next PDU to be input into the reception buffer is awaited.