Method and apparatus for packet data unit processing for retransmission

An apparatus for processing a data packet for transmission in a wireless communication system, the apparatus comprising:

• circuitry configured to control operations of:
• (A) when a data packet as a new Service Data Unit (SDU) is determined to be received from a first layer of a protocol used in the wireless communication system,
• creating, for a given new SDU, a new entry in an SDU Information Queue (SIQ) indicating:
• a Start Address set to a system memory address of the given new SDU,
• a Total Size set to a size of the given new SDU,
• a Remaining Length set to the size of the given new SDU,
• a Previous Pointer set to (i) an index of a previously received SDU in the SIQ, when the SIQ includes an entry for the previously received SDU, and (ii) null, when the given new SDU is a first received SDU, and
• a Next Pointer set to a next free element in the SIQ configured to store information of a next received SDU;
• (B) when a transmission resource is determined to be allocated and a retransmission PDU is determined not to be pending in a PDU Retransmission Information Queue (PRIQ),
• (a) preparing a data packet as a Protocol Data Unit (PDU) at a second layer of the protocol for transmission, in which the second layer is at a lower level in the protocol than the first layer,
• (b) updating a PDU Information Queue (PIQ) by setting:
• a PDU Sequence Number of the PDU to a next sequence number in a predetermined range of sequence numbers,
• a Total Size to an entire size of the PDU,
• a Total Number of SDU Segments packed to a total number of whole SDUs or SDU segments to be packed in the PDU, and
• a Pointer to a SDU Segment Information Queue (SSIQ) to an index of the SSIQ to be updated with information about the whole SDUs or SDU segments packed into the PDU;
• (c) setting the index of the SSIQ to be updated to an index in the SIQ of a SDU or a segment of an SDU packed in the PDU,
• (d) when a whole SDU or a first segment of a SDU is packed in the PDU, setting a SDU Segment Address Offset to the Start Address,
• (e) when a whole SDU or the first segment of a SDU is not packed in the PDU, setting the SDU Segment Address Offset to a sum of the Start Address and the Total Size less the Remaining Length, and
• (f) setting:
• a SDU Segment Length to a size of the SDU or the SDU segment packed in the PDU,
• a SDU Segment Offset to a memory address of the PDU in which the SDU or the SDU segment is packed,
• the Previous Pointer to an index of a most recently formed entry in the SSIQ,
• the Next Pointer to an index of a next free entry in the SSIQ, and
• the Remaining Length to (i) zero, when a whole SDU is packed in the PDU, and (ii) the Remaining length minus the SDU segment length, when at least one SDU segment remains and is not to be packed in the PDU;
• and
• (C) when a transmission resource is determined to be allocated and a retransmission PDU is determined to be pending in the PRIQ,
• updating the PRIQ by:
• setting a Retransmitted PDU Size equal to an allocated transmission resource size, and
• preparing a PDU segment as the retransmission PDU according to the allocated transmission resource size using a PDU Segment Offset and a SDU Segment Offset of the PRIQ.

A wireless communication device comprising:

• a receiver to receive a data packet in a wireless communication system;
• and
• a processing device to control operations of:
• (A) when a data packet as a new Service Data Unit (SDU) is determined to be received from a first layer of a protocol used in the wireless communication system,
• creating, for a given new SDU, a new entry in an SDU Information Queue (SIQ) indicating:
• a Start Address set to a system memory address of the given new SDU,
• a Total Size set to a size of the given new SDU,
• a Remaining Length set to the size of the given new SDU,
• a Previous Pointer set to (i) an index of a previously received SDU in the SIQ, when the SIQ includes an entry for the previously received SDU, and (ii) null, when the given new SDU is a first received SDU, and
• a Next Pointer set to a next free element in the SIQ configured to store information of a next received SDU;
• (B) when a transmission resource is determined to be allocated and a retransmission PDU is determined not to be pending in a PDU Retransmission Information Queue (PRIQ),
• (a) preparing a data packet as a Protocol Data Unit (PDU) at a second layer of the protocol for transmission, in which the second layer is at a lower level in the protocol than the first layer,
• (b) updating a PDU Information Queue (PIQ) by setting:
• a PDU Sequence Number of the PDU to a next sequence number in a predetermined range of sequence numbers,
• a Total Size to an entire size of the PDU,
• a Total Number of SDU Segments packed to a total number of whole SDUs or SDU segments to be packed in the PDU, and
• a Pointer to a SDU Segment Information Queue (SSIQ) to an index of the SSIQ to be updated with information about the whole SDUs or SDU segments packed into the PDU;
• (c) setting the index of the SSIQ to be updated to an index in the SIQ of as SDU or a segment of an SDU packed in the PDU,
• (d) when a whole SDU or a first segment of a SDU is packed in the PDU, setting a SDU Segment Address Offset to the Start Address,
• (e) when a whole SDU or the first segment of a SDU is not packed in the PDU, setting the SDU Segment Address Offset to a sum of the Start Address and the Total Size less the Remaining Length, and
• (f) setting:
• a SDU Segment Length to a size of the SDU or the SDU segment packed in the PDU,
• a SDU Segment Offset to a memory address of the PDU in which the SDU or the SDU segment is packed,
• the Previous Pointer to an index of a most recently formed entry in the SSIQ,
• the Next Pointer to an index of a next free entry in the SSIQ, and
• the Remaining Length to (i) zero, when a whole SDU is packed in the PDU, and (ii) the Remaining length minus the SDU segment length, when at least one SDU segment remains and is not to be packed in the PDU;
• and
• (C) when a transmission resource is determined to be allocated and a retransmission PDU is determined to be pending in the PRIQ,
• updating the PRIQ by:
• setting a Retransmitted PDU Size equal to an allocated transmission resource size, and
• preparing a PDU segment as the retransmission PDU according to the allocated transmission resource size using a PDU Segment Offset and a SDU Segment Offset of the PRIQ.