Method and apparatus for transmitting and receiving a packet via high speed downlink packet access
A method and apparatus for transmitting and receiving a packet via high speed downlink packet access (HSDPA) are disclosed. At least one HSDPA medium access control (MAC-hs) service data unit (SDU) is segmented into a plurality of segments. MAC-hs protocol data units (PDUs) are generated from the segments wherein each MAC-hs PDU includes at least one segment. Each MAC-hs PDU may include one segment from a single MAC-hs SDU. The size of the segments may match to the size of the MAC-hs PDUs minus the size of the header of the MAC-hs PDU. The sizes of the segments may be determined based on the number of segments to which the MAC-hs SDU is segmented. Alternatively, each MAC-hs PDU may include a combination of segments from a plurality of MAC-hs SDUs or a combination of at least one segment from one MAC-hs SDU and at least one entire MAC-hs SDU.
1. A method for receiving a packet via high speed downlink packet access (HSDPA), the method comprising:
receiving a plurality of HSDPA medium access control (MAC-hs) protocol data units (PDUs), each MAC-hs PDU comprising at least one MAC-hs service data unit (SDU) segment and a header, the header comprising a first identifier corresponding to one of a plurality of queues associated with buffering MAC-hs SDU segments, a second identifier indicating which of a plurality of segments within a MAC-hs SDU the at least one MAC-hs SDU segment corresponds, and an indication of a length of the at least one MAC-hs SDU segment;
setting a timer upon receiving a segment of an MAC-hs SDU, wherein the timer is configured to reset upon receiving a second segment of the MAC-hs SDU;
storing the segment of the MAC-hs SDU for reassembly in a queue corresponding to the first identifier; and
discarding the stored segment of the MAC-hs SDU on a condition that the timer expires before the second segment of the MAC-hs SDU has been received.
2. The method of claim 1 , further comprising:
reassembling segments of the MAC-hs SDU in the MAC-hs PDUs to the MAC-hs SDU based on a condition that the second segment of the MAC-hs SDU has been received before the timer expires.
3. The method of claim 1 , further comprising:
determining whether a transmission has failed for the second segment of the MAC-hs SDU.
4. The method of claim 1 , further comprising:
discarding segments of the MAC-hs SDU that are waiting for reassembly on a condition that the second segment of the MAC-hs SDU is lost.
5. The method of claim 1 , further comprising:
detecting hybrid automatic repeat request (H-ARQ) process failure for a segment of a second MAC-hs SDU; and
discarding at least one other segment of the second MAC-hs SDU that are waiting for reassembly.
6. A wireless transmit/receive unit (WTRU) for receiving a packet via high speed downlink packet access (HSDPA), the WTRU comprising:
a processor configured to:
receive a plurality of HSDPA medium access control (MAC-hs) protocol data units (PDUs), each MAC-hs PDU comprising at least one MAC-hs service data unit (SDU) segment and a header, the header comprising a first identifier corresponding to one of a plurality of queues associated with buffering MAC-hs SDU segments, a second identifier indicating which of a plurality of segments within a MAC-hs SDU the at least one MAC-hs SDU segment corresponds, and an indication of a length of the at least one MAC-hs SDU segment;
set a timer upon receiving a segment of an MAC-hs SDU, wherein the timer is configured to reset upon receiving a second segment of the MAC-hs SDU;
store the segment of the MAC-hs SDU for reassembly in a queue corresponding to the first identifier; and
discard the segment of the MAC-hs SDU on a condition that the timer expires before the second segment of the MAC-hs SDU has been received.
7. The WTRU of claim 6 , wherein the processor is configured to reassemble segments of the MAC-hs SDU in the MAC-hs PDUs to the MAC-hs SDU based on a condition that the second segment of the MAC-hs SDU has been received before the timer expires.
8. The WTRU of claim 6 , wherein the processor is configured to determine whether a transmission has failed for the second segment of the MAC-hs SDU.
9. The WTRU of claim 6 , wherein the processor is configured to discard MAC-hs SDU segments stored for reassembly on a condition that the second segment of the MAC-hs SDU is lost.
10. The WTRU of claim 6 , wherein the processor is configured to flush all segments of the MAC-hs SDU that are waiting for reassembly from a buffer on a condition that the timer expires before all segments of the MAC-hs SDU have been received.
11. The WTRU of claim 6 , wherein the processor is configured to discard at least one segment of a second MAC-hs SDU that are waiting for reassembly on a condition that hybrid automatic repeat request (H-ARQ) process failure is detected for another segment of the second MAC-hs SDU.
12. The method of claim 1 , wherein all segments of the MAC-hs SDU that are waiting for reassembly are flushed from a buffer on a condition that the timer expires before all segments of the MAC-hs SDU have been received.