Method and apparatus for receiving data packets

A receiver receives a data packet with a header and a payload. The payload includes at least one full service data unit, one or two service data unit fragments, or at least one full service data unit and at least one service data unit fragment, where a service data unit fragment is only located (i) at the beginning of the payload or at the end of the payload or (ii) at the beginning of the payload and at the end of the payload. The header includes a single field consisting of a first bit and a second bit, even when a number of full service data units and service data unit fragments in the payload is more than two, the single field indicating whether (i) the payload begins with a fragment of a service data unit and (ii) the payload ends with a service data unit fragment. Digital signal processing circuitry processes the header to determine processing for the payload.