Method and apparatus for transmitting and receiving packet data unit in mobile communication system

An apparatus for transmitting a packet data unit (PDU) in a mobile communication system, the apparatus comprising:

• a controller configured to
• obtain a header including a length indicator (LI) field and an extension bit field that indicates whether a data field follows or a second set of an extension bit field and an LI field follows, wherein the LI field indicates a length of a corresponding data field and the extension bit field indicates whether a data field follows or a set of an extension bit field and an LI field follows, and
• generate the PDU including the header and at least one data field;
• and
• a transmitter configured to transmit the PDU,
• wherein the extension bit field is placed prior to the LI field in the set of the extension bit field and the LI field, and
• wherein an LI field is present for every data field except a last data field.

A method for receiving a packet data unit (PDU) by a reception apparatus including a controller and a receiver in a mobile communication system, the method comprising:

• receiving by the receiver, the PDU including a header and at least one data field, wherein the header includes a length indicator (LI) field and an extension bit field, the LI field indicating a length of a corresponding data field and the extension bit field indicating whether a data field follows or a set of an extension bit field and an LI field follows;
• obtaining, by the controller, the header including the LI field and the extension bit field in the PDU;
• and
• processing, by the controller, the at least one data field in the PDU, based the obtained header including the LI field and the extension bit field,
• wherein the extension bit field is placed prior to the LI field in the set of the extension bit field and the LI field, and
• wherein an LI field is present for every data field except a last data field.

An apparatus for receiving a packet data unit (PDU) in a mobile communication system, the method comprising:

• a receiver configured to receive the PDU including a header and at least one data field, wherein the header includes a length indicator (LI) field and an extension bit field, the LI field indicating a length of a corresponding data field and the extension bit field indicating whether a data field follows or a set of an extension bit field and a LI field follows;
• and
• a controller configured to
• obtain the header including the LI field and the extension bit field in the PDU, and
• process the at least one data field in the PDU, based the obtained header including the LI field and the extension bit field,
• wherein the extension bit field is placed prior to the LI field in the set of the extension bit field and the LI field, and
• wherein an LI field is present for every data field except a last data field.