# Patent

## Title
Method and apparatus for packet data unit processing

## Abstract

In data communication systems, data packet processing for transmission and reception may go through different stages such as segmentation or packing of the data packets on the transmission side and duplicate detection, reordering, and reassembly on the reception side. For reliable data transmission between the peers, acknowledgement based retransmission protocol known as Automatic Repeat Request may be used where each retransmission can further segment the previously transmitted data packets. This type of data processing may lead to high memory requirements and high processing requirements. A method and apparatus are disclosed that maintain additional information about the data packets which enables virtual segmentation and packing on the transmitter side and on the receiver side, virtual duplicate detection, reordering and reassembly. Performing the segmentation, packing, duplicate detection, reordering and reassembly operations in virtual manner reduce the memory and processing requirements and this may lead to reduced power consumption and improved user experience.

## Background
BACKGROUND
In data communication systems, data packet processing for transmission and reception may go through different stages such as segmentation, concatenation or packing of the data packets on the transmission side and duplicate detection, reordering, and reassembly on the reception side. Also in some data communication systems, for reliable data transmission between the peers, an acknowledgement (positive or negative) based retransmission protocol known as Automatic Repeat Request (ARQ) may be used where each retransmission can further segment the previously transmitted data packets. This type of data processing may lead to high memory requirements and high processing requirements.
The services and features of data communication systems may be implemented in distinct layers. The data packets given by the application or upper layer of any protocol may be referred as Service Data Unit (SDU) and the data unit provided to the lower layer is referred to as Protocol Data Unit (PDU) as shown in FIG. 1. On the transmission side a protocol entity works on the SDU as the input and performs data packet processing. On the receiving side, a protocol entity works on a PDU as the input and performs data packet processing. The data packet processing on the transmission side may add headers or footers or both to the SDU. The data packet processing on the reception side may remove headers or footers or both from the PDU and provides an SDU to the application or upper layer.
There are many different scenarios in which an SDU may be processed by a protocol entity to generate PDUs using segmentation and packing. Examples of the data packet processing scenarios on transmission side are illustrated in FIG. 2. Examples of the processing scenarios illustrated in FIG. 2 include transmission of an SDU in a PDU without segmentation or packing, segmentation of an SDU and transmission in two different PDUs, and segments of two different SDUs packed and transmitted in a single PDU. In some cases, due to errors in transmission or reception, a PDU may need to be retransmitted. When a PDU is retransmitted, in order to match the available transmission resource size, it may have to be segmented into smaller size called PSU segments. This example is illustrated in FIG. 2 by the PDUm+4 which is retransmitted as a PDU segments PDUSx and PDUSx+1. Similarly, examples of the packet data processing scenarios on the reception side are illustrated FIG. 3. Examples of the processing scenarios illustrated in FIG. 3 include reception of an SDU in a PDU without unpacking or reassembly, reassembly of an SDU from reception of two different PDUs, unpacking of two different SDUs from a single PDU and reassembling an SDU from two different PDUs, and reassembling a retransmitted PDU from multiple PDU segments.
SUMMARY
A method and apparatus are disclosed that maintain additional information about the data packets which enables virtual segmentation and packing on the transmitter side and similarly, on the receiver side, virtual duplicate detection, reordering and reassembly. Performing the segmentation, packing, duplicate detection, reordering and reassembly operations in virtual manner reduce the memory and processing requirements and this may lead to reduced power consumption and improved user experience.
In accordance with an aspect of the present invention, a method for processing a data packet for transmission in a wireless communication system may include: (A) controlling, by a processing device, 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; and (B) controlling, by the processing device, when a transmission resource is determined to be allocated, 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, 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.
In one alternative, the method may include controlling, by the processing device, repeatedly performing (A) and (B), until a result of a determination after (B) is performed is all new received SDUs in the SIQ have been transmitted as a given PDU.
In one alternative, the first layer may be an application layer.
In one alternative, the PDU may include one or more SDUs or SDU Segments.
In one alternative, the method may include: (C) controlling, by the processing device, when a Transmission Completion Status is received for a given PDU having a given Sequence Number, searching the PIQ for an information element corresponding to the given Sequence Number, based on a Pointer to the SSIQ of the information element determined from the searching the PIQ, identifying an associated information element in the SSIQ, and from an SIQ Index of the associated information element in the SSIQ, identifying an information element in the SIQ to which the Transmission Completion Status corresponds; and (D) controlling, by the processing device, performing (C) until a Transmission Completion Status for all SDU segments of a given SDU is received, when the Transmission Completion status for all SDU segments of the given SDU is determined to be received, releasing the information element in the SIQ corresponding to the given SDU and the information element in the SSQI corresponding to each SDU segment of the given SDU, updating the Next Pointer and the Previous Pointer with regard to each remaining element in the SIQ and the SSIQ, and releasing the information element in the PIQ corresponding to the Sequence Number of the PDU for which the Transmission Complete Status is received.
In one alternative, the method may include: (E) controlling, by the processing device, repeatedly performing (C) and (D), until a result of a determination after (D) is performed is all SDUs received are transmitted successfully.
In accordance with an aspect of the present invention, a method for processing a data packet received in a wireless communication system may include: (A) controlling, by a processing device, when the data packet as a Protocol Data Unit (PDU) is successfully received at a wireless communication device of the system without retransmission, determining whether another PDU with a same Sequence Number as a Sequence Number of the received PDU exists as an entry in a ReOrder Information Queue (ROIQ), when the Sequence Number of the received PDU is determined to be the same as the Sequence Number of the another PDU, discarding the recently received PDU, when the Sequence Number of the received PDU is determined not to be the same as the Sequence Number of the another PDU, creating a new entry in the ROIQ for the received PDU, and setting in the ROIQ: a PDU Sequence Number to the Sequence Number of the received PDU, a PDU Status to (i) complete PDU, when the received PDU is complete and (ii) PDU segment, when the received PDU is not complete, a PDU Memory Address to a starting memory address of the received PDU stored in a system memory, a Total Size to a size of the received PDU, a Previous Pointer to an index of a previously received PDU in the ROIQ, and a Next pointer to an index of a next free element in the ROIQ; (B) controlling, by the processing device, repeatedly performing (A), until a PDU with any Sequence Number up to the Sequence Number of the received PDU is determined not to be missing, and when a PDU with any sequence number up to the sequence number of the received PDU is determined not to be missing, reordering each received PDU for reassembly into a reassembled SDU, and setting in a ReAssembly Information Queue (RAIQ): an Address to the system memory address of the received PDU, a Segment Size to a size of a SDU or SDU segment in the received PDU, and based on information in a header of the PDU received, a SDU Status to indicate one of (i) non-segmented (SDU_COMPLETE), (ii) segmented and first part of a parent SDU thereof (SDU_FIRST_−SEG), (iii) segmented and last part of a parent SDU thereof (SDU_LAST_SEG), and (iv) segmented and an intermediate part of a parent SDU thereof (SDU_MIDDLE_SEG); and (C) controlling, by the processing device, performing (A) and (B) repeatedly, until a result of a determination after (B) is performed is at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, and when at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, delivering as the reassembled SDU a complete SDU to a predetermined layer of a protocol of the wireless communication system with, for each SDU segment in the complete SDU, information of a memory offset and size.
In accordance with an aspect of the present invention, an apparatus for processing a data packet for transmission in a wireless communication system may include 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; and (B) when a transmission resource is determined to be allocated, (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 PDIU 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.
In one alternative of the apparatus, the circuitry may be configured to control repeatedly performing (A) and (B), until a result of a determination after (B) is performed is all new received SDUs in the SIQ have been transmitted as a given PDU.
In one alternative of the apparatus, the first layer may be an application layer.
In one alternative of the apparatus, the PDU may include one or more SDUs or SDU Segments.
In one alternative of the apparatus, the circuitry may be configured to control operations of: (C) when a transmission Completion Status is received for a given PDU having a given Sequence Number, searching the PIQ for an information element corresponding to the given Sequence Number, based on a Pointer to the SSIQ of the information element determined from the searching the PIQ, identifying an associated information element in the SSIQ, and from an SIQ Index of the associated information element in the SSIQ, identifying an information element in the SIQ to which the Transmission Completion Status corresponds; and (D) performing (C) until a Transmission Completion Status for all SDU segments of a given SDU is received, when the Transmission Completion status for all SDU segments of the given SDU is determined to be received, releasing the information element in the SIQ corresponding to the given SDU and the information element in the SSQI corresponding to each SDU segment of the given SDU, updating the Next Pointer and the Previous Pointer with regard to each remaining element in the SIQ and the SSIQ, and releasing the information element in the PIQ corresponding to the Sequence Number of the PDU for which the Transmission Complete Status is received.
In one alternative of the apparatus, the circuitry may be configured to control operation of: (E) repeatedly performing (C) and (D), until a result of a determination after (D) is performed is all SDUs received are transmitted successfully.
In accordance with an aspect of the present invention, an apparatus for processing a data packet received in a wireless communication system, may include circuitry configured to control operations of: (A) when the data packet as a Protocol Data Unit (PDU) is successfully received at a wireless communication device of the system without retransmission, determining whether another PDU with a same Sequence Number as a Sequence Number of the received PDU exists as an entry in a ReOrder Information Queue (ROIQ), when the Sequence Number of the received PDU is determined to be the same as the Sequence Number of the another PDU, discarding the recently received PDU, when the Sequence Number of the received PDU is determined not to be the same as the Sequence Number of the another PDU, creating a new entry in the ROIQ for the received PDU, and setting in the ROIQ: a PDU Sequence Number to the Sequence Number of the received PDU, a PDU Status to (i) complete PDU, when the received PDU is complete and (ii) PDU segment, when the received PDU is not complete, a PDU Memory Address to a starting memory address of the received PDU stored in a system memory, a Total Size to a size of the received PDU, a Previous Pointer to an index of a previously received PDU in the ROIQ, and a Next pointer to an index of a next free element in the ROIQ; (B) repeatedly performing (A), until a PDU with any Sequence Number up to the Sequence Number of the received PDU is determined not to be missing, and when a PDU with any sequence number up to the sequence number of the received PDU is determined not to be missing, reordering each received PDU for reassembly into a reassembled SDU, and setting in a ReAssembly Information Queue (RAIQ): an Address to the system memory address of the received PDU, a Segment Size to a size of a SDU or SDU segment in the received PDU, and based on information in a header of the PDU received, a SDU Status to indicate one of (i) non-segmented (SDU_COMPLETE), (ii) segmented and first part of a parent SDU thereof (SDU_FIRST_SEG), (iii) segmented and last part of a parent SDU thereof (SDU_LAST_SEG), and (iv) segmented and an intermediate part of a parent SDU thereof (SDU_MIDDLE_SEG); and (C) performing (A) and (B) repeatedly, until a result of a determination after (B) is performed is at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, and when at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, delivering as the reassembled SDU a complete SDU to a predetermined layer of a protocol of the wireless communication system with, for each SDU segment in the complete SDU, information of a memory offset and size.
In accordance with an aspect of the present invention, a wireless communication device may include: a transmitter to transmit a data packet in a wireless communication system; and a processing device configured to control processing of the data packet for transmission in the wireless communication system. The processing device may be 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; and (B) when a transmission resource is determined to be allocated, (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 PDIU 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, 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.
In one alternative of the wireless communication device, the processing device may be configured to control repeatedly performing (A) and (B), until a result of a determination after (B) is performed is all new received SDUs in the SIQ have been transmitted as a given PDU.
In one alternative of the wireless communication device, the PDU may include one or more SDUs or SDU Segments.
In one alternative of the wireless communication device, the processing device may be configured to control operations of: (C) when a Transmission Completion Status is received for a given PDU having a given Sequence Number, searching the PIQ for an information element corresponding to the given Sequence Number, based on a Pointer to the SSIQ of the information element determined from the searching the PIQ, identifying an associated information element in the SSIQ, and from an SIQ Index of the associated information element in the SSIQ, identifying an information element in the SIQ to which the Transmission Completion Status corresponds; and (D) performing (C) until a Transmission Completion Status for all SDU segments of a given SDU is received, when the Transmission Completion status for all SDU segments of the given SDU is determined to be received, releasing the information element in the SIQ corresponding to the given SDU and the information element in the SSQI corresponding to each SDU segment of the given SDU, updating the Next Pointer and the Previous Pointer with regard to each remaining element in the SIQ and the SSIQ, and releasing the information element in the PIQ corresponding to the Sequence Number of the PDU for which the Transmission Complete Status is received.
In one alternative of the wireless communication device, the circuitry may be configured to control operation of: (E) repeatedly performing (C) and (D), until a result of a determination after (D) is performed is all SDUs received are transmitted successfully.
In accordance with an aspect of the present invention, a wireless communication device may include a receiver to receive a data packet in a wireless communication system; and a processing device to control operations of: (A) when the data packet as a Protocol Data Unit (PDU) is successfully received at the wireless communication device without retransmission, determining whether another PDU with a same Sequence Number as a Sequence Number of the received PDU exists as an entry in a ReOrder Information Queue (ROIQ), when the Sequence Number of the received PDU is determined to be the same as the Sequence Number of the another PDU, discarding the recently received PDU, when the Sequence Number of the received PDU is determined not to be the same as the Sequence Number of the another PDU, creating a new entry in the ROIQ for the received PDU, and setting in the ROIQ: a PDU Sequence Number to the Sequence Number of the received PDU, a PDU Status to (i) complete PDU, when the received PDU is complete and (ii) PDU segment, when the received PDU is not complete, a PDU Memory Address to a starting memory address of the received PDU stored in a system memory, a Total Size to a size of the received PDU, a Previous Pointer to an index of a previously received PDU in the ROIQ, and a Next pointer to an index of a next free element in the ROIQ; (B) repeatedly performing (A), until a PDU with any Sequence Number up to the Sequence Number of the received PDU is determined not to be missing, and when a PDU with any sequence number up to the sequence number of the received PDU is determined not to be missing, reordering each received PDU for reassembly into a reassembled SDU, and setting in a ReAssembly Information Queue (RAIQ): an Address to the system memory address of the received PDU, a Segment Size to a size of a SDU or SDU segment in the received PDU, and based on information in a header of the PDU received, a SDU Status to indicate one of (i) non-segmented (SDU_COMPLETE), (ii) segmented and first part of a parent SDU thereof (SDU_FIRST_SEG), (iii) segmented and last part of a parent SDU thereof (SDU_LAST_SEG), and (iv) segmented and an intermediate part of a parent SDU thereof (SDU_MIDDLE_SEG); and (C) performing (A) and (B) repeatedly, until a result of a determination after (B) is performed is at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, and when at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, delivering as the reassembled SDU a complete SDU to a predetermined layer of a protocol of the wireless communication system with, for each SDU segment in the complete SDU, information of a memory offset and size.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a layered architecture of a data communication system.
FIG. 2 illustrates example segmentation and packing scenarios in a protocol entity at the transmitter side.
FIG. 3 illustrates an example reassembly and unpacking scenarios in a protocol entity at the receiver side.
FIG. 4 illustrates details of the different information queues maintained by a transmitter protocol entity according to the aspects of the present invention.
FIG. 5 illustrates example interactions amongst different queues by a transmitter protocol entity according to the aspects of the present invention.
FIG. 6 illustrates an example flow diagram for processing steps when a new SDU is received at a transmitter protocol entity according to aspects of the present invention.
FIG. 7 illustrates an example flow diagram for processing steps when an SDU transmission completion status is received by a transmitter protocol entity according to aspects of the present invention.
FIG. 8 illustrates details of the different information queues maintained by a receiver protocol entity according to the aspects of the present invention.
FIG. 9 illustrates example interactions amongst different queues by a receiver protocol entity according to the aspects of the present invention.
FIG. 10 illustrates an example flow diagram for processing steps when a new PDU is received at a receiver protocol entity according to aspects of the present invention.
FIG. 11 illustrates a conventional mobile wireless communication system.
FIG. 12 illustrates a wireless mobile station diagram, which may be employed with aspects of the invention described herein.
FIG. 13 illustrates an application processor subsystem for a wireless mobile station, which may be employed with aspects of the invention described herein.
FIG. 14 illustrates a baseband subsystem for a wireless mobile station, which may be employed with aspects of the invention described herein.
FIG. 15 illustrates a Radio Frequency (RF) subsystem for a wireless mobile station, which may be employed with aspects of the invention described herein.



DETAILED DESCRIPTION
The foregoing aspects, features and advantages of the present invention will be further appreciated when considered with reference to the following description of exemplary embodiments and accompanying drawings, wherein like reference numerals represent like elements. In describing the exemplary embodiments of the invention illustrated in the appended drawings, specific terminology will be used for the sake of clarity. However, the invention is not intended to be limited to the specific terms used.
According to an aspect of the present invention the data packet processing is performed by maintaining the required information for the SDUs, PDUs and SDU segments in their respective information queues. According to an aspect of the present invention, in case where the PDU processing does not require retransmission, three different information queues may be created and maintained to enable virtual data packet processing as shown in FIG. 4. Next, each of the information queues is described in detail.
The SDU Information Queue (SIQ) maintains the following information:

    
    
        Start Address of an SDU
        Total Size of an SDU
        Remaining Length after an SDU has been segmented
        Previous Pointer and Next Pointer to form bidirectional link between each element in the SIQ for fast traversal through the elements in the queue.
    
    


The PDU Information Queue (PIQ) maintains the following information:

    
    
        PDU Sequence Number
        Total Size of a PDU
        Total number of SDU segments packed into a PDU
        Pointer to SDU Segment Information Queue (SSIQ). Each SDU segment in a PDU has an element in the SSIQ.
    
    


The SSIQ maintains the following information:

    
    
        SIQ Index for an SDU to which a SDU segment belongs. This index is required to link the SDU segment information element directly to the SIQ when providing the transmission completion status for the application or upper layer and to release the memory of the SDU.
        SDU Segment Address Offset
        SDU Segment Length
        SDU Segment Offset
        Previous Pointer and Next Pointer to form bidirectional link between each element in the SSIQ for fast traversal through the elements in the queue.
    
    


The relationship among the three queues is illustrated in FIG. 5. According to another aspect of the present invention the following are steps performed in the packet data processing at the transmission side. Whenever an SDU is received from an application or higher layer, the SIQ is updated as follows.

    
    
        Start Address of the SDU is set to the start address of the SDU in the system memory
        Total Size of the SDU is set to the size of the entire SDU
        Remaining Length of the SDU is set to the size of the entire SDU
        Previous Pointer may point to the SIQ index for a previously received SDU
        Next Pointer may point to the next free SIQ index where the next SDU information may be stored
    
    


When a PDU is prepared for transmission, the SIQ, the PIQ and the SSIQ are updated as follows.

    
    
        The PIQ is updated as follows:
        
            PDU Sequence Number is set to the next sequence number to be given for the PDU under preparation. The sequence number is a running number from 0 to N−1 (where N could be implementation dependent parameter, for example N may be 2048).
            Total Size of the PDU is set to the entire PDU size prepared for transmission. This PDU may carry one or more SDUs or SDU Segments.
            Total Number of SDU Segments packed into the PDU is set to total number of whole SDUs or SDU segments that are packed to form the current PDU.
            Pointer to SSIQ is set to the index of the SSIQ which is to be updated with the information about the SDU segment under preparation for transmission. This indexing forms a logical link between the PIQ and the SSIQ.
        
        
        The SSIQ is updated as follows:
        
            The SSIQ information element selected in previous step is updated with the SIQ index of the SDU or the segment of an SDU packed in the current PDU. This index is required to link the SSIQ information element directly to the SIQ when providing the transmission completion status for the application or the upper layer and to release the memory of the SDU.
            If a full SDU or the first segment of an SDU is packed in a PDU, the SDU Segment Address Offset is set to the Start Address of the SDU. If a non-first SDU segment is packed in a PDU, the SDU Segment Address Offset is set to Start Address+(Total Size−Remaining Length).
            SDU Segment Length is set to the size of the SDU or SDU segment that is packed in the PDU.
            SDU Segment Offset is set to the memory address of the PDU in which the SDU or the SDU segment is packed.
            Previous Pointer points to the most recently formed SSIQ index prior to the current one.
            Next Pointer points to the next free SSIQ index where the next SDU segment information may be stored.
        
        
        The SIQ is updated as follows:
        
            After an SDU has been segmented, the Remaining Length field is updated as follows:
            
                If a full SDU is packed then it is set to 0
                If a segment of an SDU is packed and remaining SDU segments are to be left unpacked then this field may be set to the remaining size of the SDU that may be considered for next transmission.
            
            
        
        
    
    


When a PDU is successfully transmitted, the PIQ is first checked and then through the link from the PIQ to the SSIQ and from SSIQ to the SIQ, the SIQ is traversed and the SDU transmission completion notification is provided to the application or to the upper layer for the relevant SDU as follows.

    
    
        At the successful transmission completion of a PDU, the PDU Sequence Number may be given as an indication to traverse the information queues.
        From the PDU Sequence Number the PIQ may be traversed and the information element for the PDU may be identified.
        From the Pointer to the SSIQ stored in the PIQ, the associated information element in the SSIQ may be identified.
        From the SIQ Index stored in the SSIQ of the selected information element the SIQ information element may be indexed.
        If transmission completion status is received for all the SDU segments of an SDU, then the SDU memory may be released and the bi-directional link may be formed with the previous and next link of the current SIQ information element.
        The SSIQ information element may be released and the bi-directional link may be formed with the previous and next link of the current SSIQ information element.
        The PIQ indexed with the PDU sequence number may be set to free.
    
    


The transmitter side processing aspects of the present invention are illustrated in the flow diagram contained in FIG. 6. At processing stage 602, the SIQ, PIQ and SSIQ data structures are created. At processing stage 604, a transmitter side protocol entity waits for a new SDU from an application or upper layer. If a new SDU is received, the processing flow continues at processing stage 606, where the various fields of the SIQ are updated. The Start Address is updated with the system memory address of the newly received SDU. The Total Size field is set equal to the size of the newly received SDU. The Remaining Length field is also set equal to the size of the newly received SDU. The Previous Pointer is set to the index of a previously received SDU. In case of a very first SDU, the Previous Pointer is set to null to indicate the end of the queue. The Next Pointer is set to the next free element in the SIQ. The processing then continues at processing stage 607. Returning to processing stage 604, if no new SDU is received from an application or upper layer, the processing continues at processing stage 607. At processing stage 607, determination is made whether transmission resources are allocated or not. If transmission resources are not allocated, the processing returns to processing stage 604. If transmission resources are allocated, the processing continues at processing stage 608 where a PDU is prepared for transmission. Next at processing stage 610, the next free element in PIQ is updated. The PDU Sequence Number field is updated by the next sequence number in the range 0 to N−1 as described earlier. The Total Size field is updated according to the size of the allocated resources. The Number of SDUs Packed field is updated with the total number of SDUs or SDU segments packed to form the current PDU. The Pointer to SSIQ field is updated with the index of the SSIQ which is to be updated with the information about the SDUs or SDU segments that are packed in the current PDU. Next the processing continues at processing stage 612, where the SSIQ is updated. At processing stage 612, the SIQ Index field is updated with the SIQ index of the SDU or the SDU segment that is packed in the current PDU. At processing stage 614, a determination is made whether a complete SDU or a first segment of an SDU is packed in current PDU. If it is the complete SDU or the first segment of the SDU, the processing continues at processing stage 616 where the SDU Segment Address Offset field in the SSIQ is updated with the SDU Start Address. Returning to processing stage 614, if it is not the full SDU or the first segment of the SDU, the processing continues at processing stage 618 where the SDU Segment Address Offset field of the SSIQ is updated with the value (SDU Start Address+(Total Size−Remaining Length)). The further processing after stages 616 or 618 continues at processing stage 620 where the remaining fields of the SSIQ are updated. The SDU Segment Length field is updated with the size of the SDU or SDU segment packed. The SDU Segment Offset is updated with the memory address of the PDU in which the SDU or SDU segment is packed. The Previous Pointer is updated with the index of the most recently formed entry in the SSIQ. The Next Pointer is updated with the index of the next free element in the SSIQ. The processing then continues at processing stage 622 where the Remaining Length field in the SIQ index for the SDU that is packed in the current PDU is updated as Remaining Length=Remaining Length−SDU Segment Length. At processing stage 624, determination is made whether all the SDUs in the queue are transmitted or not. If not all the SDUs are transmitted then the processing continues at processing stage 604. If all the SDUs are transmitted then the processing suitably terminates at stage 626.
The transmitter side processing aspects of the present invention when a Transmission Completion status is received from the peer entity are illustrated in the flow diagram contained in FIG. 7. The processing relevant to the present invention begins at processing stage 702, where the transmitter entity waits for receiving Transmission Completion status from peer entity. At processing stage 704, indication of Transmission Completion status for a PDU with a particular PDU Sequence Number is received from a peer entity. At processing stage 706, the PIQ is searched to find the element corresponding to the Sequence Number of the successfully transmitted PDU. From the found PIQ element, the Pointer to SSIQ field is used to identify the associated element in the SSIQ. At processing stage 710, from the identified SSIQ information element, the SIQ Index field is used to identify the SIQ information element to which the received Transmission Completion status corresponds. At processing stage 712, determination is made whether Transmission Completion status is received for all the SDU segments of an SDU. If the Transmission Completion status is not received for all the SDU segments of an SDU, the processing returns to the processing stage 702. If the Transmission Completion status is received for all the SDU segments of an SDU, the processing continues at processing stage 714. At processing stage 714, the SIQ is updated by freeing the information element for the SDU whose transmission is completed successfully. The Previous and Next Pointers are updated to maintain the bidirectional link in the SIQ for the remaining elements in the queue. At processing stage 716, the information elements from SSIQ corresponding to the successfully transmitted SDU segments are freed. The Previous and Next Pointers are updated to maintain the bidirectional link in the SSIQ for the remaining elements in the queue. At processing stage 718, the information element from PIQ corresponding to the successfully transmitted PDU Sequence Number is freed. At processing stage 720, determination is made whether all the SDUs are transmitted successfully. If not all the SDUs are transmitted successfully, the processing returns to stage 702. Otherwise, the processing suitably terminates at stage 722.
For the packet data processing at the reception side, similar method as that of the transmission side may be used. However, in this case PDUs are inputs and SDUs are formed as an output by the protocol entity.
According to an aspect of the present invention, if the PDU processing does not require retransmission then two different information queues are created and maintained in the receiving side to enable virtual data packet processing as shown in FIG. 8. Next, each of the information queues is described in detail.
The ReOrder Information Queue (ROIQ) maintains the following information:

    
    
        PDU Sequence Number
        Total Size of the received PDU
        PDU Memory Address
        PDU Status which indicates whether a complete PDU or only a segment of a PDU is received
        Previous and Next pointers to form bidirectional link between each element in the ROIQ for fast traversal of the elements in the queue
    
    


The ReAssembly Information Queue (RAIQ) maintains the following information:

    
    
        The address where the SDU or SDU segment is present in the PDU memory
        SDU Segment Size
        SDU Status
        
            SDU_COMPLETE: The SDU is non-segmented
            SDU_FIRST_SEG: The SDU is segmented and is the first part of its parent SDU
            SDU_LAST_SEG: The SDU is segmented and is the last part of its parent SDU
            SDU_MIDDLE_SEG: The SDU is segmented and is an intermediate part of its parent SDU
        
        
        Previous and Next pointers to form bidirectional link between each element in the RAIQ for fast traversal of the elements in the queue
    
    


The relationship among the three queues is illustrated in FIG. 9. According to another aspect of the present invention, the following are the steps performed in the packet data processing at the reception side when a PDU is received without a retransmission:

    
    
        1. Detect and discard duplicate PDU and do reordering of the received PDUs
        
            a. If the sequence number of the newly received PDU already has an entry in the ROIQ then discard the recently received PDU as duplicate
        
        
        2. Whenever a PDU is received that is not a duplicate, create an entry in the ROIQ and update the following information:
        
            a. PDU Sequence Number with the received PDU Sequence Number
            b. PDU Status set to complete PDU if the PDU is complete PDU else the PDU status is set to PDU segment
            c. PDU Memory Address is set to the start memory address of the received PDU stored in the system memory
            d. Total Size of the PDU is set to the complete PDU size that is received
            e. The Previous and Next pointer are updated to maintain the bidirectional link
        
        
        3. After the PDU information is stored in ROIQ, check if there is a possibility for SDU reassembly and if the reassembly is possible, update the entry in the RAIQ.
        
            a. If there is no missing PDU sequence number up to the newly received PDU sequence number then reorder the PDUs to start the SDU reassembly
            b. If an SDU is considered for reassembly then store the following information in the RAIQ:
            
                i. The address where the SDU or SDU segment is present in the PDU memory
                ii. SDU or SDU segment size received in the PDU
                iii. SDU Status set to either one of the following based on the information received in the PDU header
                
                    SDU_COMPLETE: The SDU is non-segmented
                    SDU_FIRST_SEG: The SDU is segmented and is the first part of its parent SDU
                    SDU_LAST_SEG: The SDU is segmented and is the last part of its parent SDU
                    SDU_MIDDLE_SEG: The SDU is segmented and is an intermediate part of its parent SDU
                
                
                iv. When a complete SDU is received and when the SDU status is set to SDU_COMPLETE then deliver the complete SDU to the application or upper layer with the list consisting of memory offset and the size for each of the SDU segment that forms the complete SDU
            
            
        
        
    
    


The receiver side processing aspects of the present invention are illustrated in the flow diagram contained in FIG. 10. At processing stage 1002, the ROIQ and RAIQ data structures are created. At processing stage 1004, a determination is made whether a new PDU is received from a peer entity. If a new PDU is not received, the processing stays at the same stage. If a new PDU is received, the processing continues at processing stage 1006, where the Sequence Number is extracted from the received PDU. The ROIQ is scanned to check whether there exists an entry with the same Sequence Number. At processing stage 1008, determination is made whether the newly received PDU is a duplicate or not. If a duplicate PDU is received, the processing continues at stage 1010, where the newly received PDU is discarded and the processing returns to the stage 1004. If the received PDU is not a duplicate, the processing continues at processing stage 1012, where a new entry is added in ROIQ and updated as follows. The Sequence Number field is updated with the sequence number of the received PDU. The PDU Status field is updated as either complete PDU or PDU segment depending on the received PDU headers. The PDU Memory Address field is updated with the received PDU system memory address. The Total Size field is updated with the size of the received PDU. The Previous Pointer field is updated with the ROIQ index of the previously received PDU. The Next Pointer is updated with the index of the next free element in the ROIQ. The processing then continues at stage 1014, where determination is made whether there are any missing PDUs up to the sequence number of the newly received PDU. If there are any missing PDUs, the processing returns to the stage 1004. If there are no missing PDUs, the processing continues at stage 1016, where the received PDUs are reordered for reassembly. At processing stage 1018, the reassembly of the PDUs to form an SDU is started by updating the RAIQ as follows. The Address field of the RAIQ is updated with the system memory address of the received PDU. The Segment Size field is updated with the size of the SDU or SDU segment received in the PDU. The SDU Status field is updated with one of the four possible values: SDU_COMPLETE, SDU_FIRST_SEG, SDU_LAST_SEG or SDU_MIDDLE_SEG. At processing stage 1020, the SDU Status in the RAIQ is checked. If the SDU Status of none of the elements in RAIQ is set to SDU_COMPLETE, the processing returns to the stage 1002. If the SDU Status is set to SDU_COMPLETE for at least one of the elements, the processing continues at processing stage 1022, where the complete SDU is delivered to an application or upper layer by providing the list of memory address and segment size pairs from the RAIQ. The processing then suitably terminates at stage 1024.
According to the aspects of the present invention, the packet data processing at any layer may be performed without using any memory copy operation for transmitted or received payload data. This reduces the required clock cycle for memory copy operation either from a processor or a Direct Memory Access (DMA) controller. Furthermore, not performing copy operation eliminates the need for allocation of multiple memories for the same packet data. Reduced copy operations and reduced storage requirements lead to reduced power consumption.
Aspects of the present invention may be applied to all types of mobile communications systems and the like, such as systems based on 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) of wireless communication standard, systems based on 3GPP Wideband Code Division Multiple Access (“WCDMA”) standard, systems based on an IEEE 802.16 wireless communication standard, etc.
Typically, as shown in FIG. 11, a wireless communication system, which is a type of data communication system, comprises elements such as client terminals or mobile stations and one or more base stations. Other network devices may also be employed, such as a mobile switching center (not shown). As illustrated in FIG. 11, the communication path from the base station (BS) to the client terminal or mobile station (MS) is referred to herein as a downlink (DL) direction or downlink channel, and the communication path from the client terminal to the base station is referred to herein as an uplink (UL) direction or uplink channel. In some wireless communication systems, the MS communicates with the BS in both the DL and UL directions. For instance, such communication is carried out in cellular telephone systems. In other wireless communication systems, the client terminal communicates with the base stations in only one direction, usually the DL. Such DL communication may occur in applications such as paging. As used herein, the terms “base station” and “network” are used interchangeably.
By way of example only, the above-described method may be implemented in a receiver, e.g., a user device such as a wireless mobile station (MS) 12 as shown in FIG. 11.
As shown in FIG. 12, MS 100 may include an application processor subsystem 101, baseband subsystem 102 and a radio frequency (RF) subsystem 104 for use with a wireless communication network. A display/user interface 106 provides information to and receives input from the user. By way of example, the user interface may include one or more actuators, a speaker and a microphone. In some mobile devices, certain combination of the application processor subsystem 101, the baseband subsystem 102 and the RF subsystem 104 are all integrated as one integrated chip.
The application processor subsystem 101 as shown in FIG. 13 may include a controller 108 such as a microcontroller, another processor or other circuitry. The baseband subsystem 102 as shown in FIG. 14 may include a controller 118 such as a microcontroller or other processor. The RF subsystem 104 as shown in FIG. 15 may include a controller 128 such as a microcontroller, another processor or other circuitry. The controller 108 desirably handles overall operation of the MS 100. This may be done by any combination of hardware, software and firmware running on the controller 108. Such a combination of hardware, software and firmware may embody any methods in accordance with aspects of the present invention.
Peripherals 114 such as a full or partial keyboard, video or still image display, audio interface, etc. may be employed and managed through the controller 108.
Aspects of the present invention may be implemented in firmware of the controller 108 of the application processor and/or the controller 118 of the baseband subsystem. In another alternative, aspects of the present invention may also be implemented as a combination of firmware and hardware of the application processor subsystem 101 and/or the baseband subsystem 102. For instance, a signal processing entity of any or all of the FIG. 14 may be implemented in firmware, hardware and/or software. It may be part of the baseband subsystem, the receiver subsystem or be associated with both subsystems. In one example, the controller 118 and/or the signal processor 110 may include or control the protocol entity circuitry. The software may reside in internal or external memory and any data may be stored in such memory. The hardware may be an application specific integrated circuit (ASIC), field programmable gate array (FPGA), discrete logic components or any combination of such devices. The terms controller and processor are used interchangeably herein.
The consumer electronics devices that may use the aspects of the invention may include smartphones, tablets, laptops, gaming consoles, cameras, video camcorders, TV, car entertainment systems, etc.
Although aspects of the invention herein have been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the aspects of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the aspects of the present invention as defined by the appended claims. Aspects of each embodiment may be employed in the other embodiments described herein.

## Claims

1. A method for processing a data packet for transmission in a wireless communication system, the method comprising:
(A) controlling, by a processing device, 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; and


(B) controlling, by the processing device, when a transmission resource is determined to be allocated,
(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.

2. The method of claim 1, further comprising:
controlling, by the processing device, repeatedly performing (A) and (B), until a result of a determination after (B) is performed is all new received SDUs in the SIQ have been transmitted as a given PDU.

3. The method of claim 1, wherein the first layer is an application layer.

4. The method of claim 1, wherein the PDU includes one or more SDUs or SDU Segments.

5. The method of claim 1, further comprising:
(C) controlling, by the processing device, when a Transmission Completion Status is received for a given PDU having a given Sequence Number,
searching the PIQ for an information element corresponding to the given Sequence Number,
based on a Pointer to the SSIQ of the information element determined from the searching the PIQ, identifying an associated information element in the SSIQ, and
from an SIQ Index of the associated information element in the SSIQ, identifying an information element in the SIQ to which the Transmission Completion Status corresponds; and

(D) controlling, by the processing device,
performing (C) until a Transmission Completion Status for all SDU segments of a given SDU is received,
when the Transmission Completion status for all SDU segments of the given SDU is determined to be received,
releasing the information element in the SIQ corresponding to the given SDU and the information element in the SSQI corresponding to each SDU segment of the given SDU,
updating the Next Pointer and the Previous Pointer with regard to each remaining element in the SIQ and the SSIQ, and
releasing the information element in the PIQ corresponding to the Sequence Number of the PDU for which the Transmission Complete Status is received.

6. The method of claim 5, further comprising:
(E) controlling, by the processing device, repeatedly performing (C) and (D), until a result of a determination after (D) is performed is all SDUs received are transmitted successfully.

7. A method for processing a data packet received in a wireless communication system, the method comprising:
(A) controlling, by a processing device, when the data packet as a Protocol Data Unit (PDU) is successfully received at a wireless communication device of the system without retransmission,
determining whether another PDU with a same Sequence Number as a Sequence Number of the received PDU exists as an entry in a ReOrder Information Queue (ROIQ),
when the Sequence Number of the received PDU is determined to be the same as the Sequence Number of the another PDU, discarding the recently received PDU,
when the Sequence Number of the received PDU is determined not to be the same as the Sequence Number of the another PDU,
creating a new entry in the ROIQ for the received PDU, and
setting in the ROIQ:
a PDU Sequence Number to the Sequence Number of the received PDU,
a PDU Status to (i) complete PDU, when the received PDU is complete and (ii) PDU segment, when the received PDU is not complete,
a PDU Memory Address to a starting memory address of the received PDU stored in a system memory,
a Total Size to a size of the received PDU, a Previous Pointer to an index of a previously received PDU in the ROIQ, and
a Next pointer to an index of a next free element in the ROIQ;



(B) controlling, by the processing device,
repeatedly performing (A), until a PDU with any Sequence Number up to the Sequence Number of the received PDU is determined not to be missing, and
when a PDU with any sequence number up to the sequence number of the received PDU is determined not to be missing,
reordering each received PDU for reassembly into a reassembled SDU, and
setting in a ReAssembly Information Queue (RAIQ):
an Address to the system memory address of the received PDU,
a Segment Size to a size of a SDU or SDU segment in the received PDU, and
based on information in a header of the PDU received, a SDU Status to indicate one of (i) non-segmented (SDU_COMPLETE), (ii) segmented and first part of a parent SDU thereof (SDU_FIRST_SEG), (iii) segmented and last part of a parent SDU thereof (SDU_LAST_SEG), and (iv) segmented and an intermediate part of a parent SDU thereof (SDU_MIDDLE_SEG); and


(C) controlling, by the processing device,
performing (A) and (B) repeatedly, until a result of a determination after (B) is performed is at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, and
when at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, delivering as the reassembled SDU a complete SDU to a predetermined layer of a protocol of the wireless communication system with, for each SDU segment in the complete SDU, information of a memory offset and size.

8. 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; and


(B) when a transmission resource is determined to be allocated,
(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 PDIU 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.

9. The apparatus of claim 8,
wherein the circuitry is configured to control repeatedly performing (A) and (B), until a result of a determination after (B) is performed is all new received SDUs in the SIQ have been transmitted as a given PDU.

10. The apparatus of claim 8, wherein the first layer is an application layer.

11. The apparatus of claim 8, wherein the PDU includes one or more SDUs or SDU Segments.

12. The apparatus of claim 8,
wherein the circuitry is configured to control operations of:
(C) when a Transmission Completion Status is received for a given PDU having a given Sequence Number,
searching the PIQ for an information element corresponding to the given Sequence Number,
based on a Pointer to the SSIQ of the information element determined from the searching the PIQ, identifying an associated information element in the SSIQ, and
from an SIQ Index of the associated information element in the SSIQ, identifying an information element in the SIQ to which the Transmission Completion Status corresponds; and

(D) performing (C) until a Transmission Completion Status for all SDU segments of a given SDU is received,
when the Transmission Completion status for all SDU segments of the given SDU is determined to be received,
releasing the information element in the SIQ corresponding to the given SDU and the information element in the SSQI corresponding to each SDU segment of the given SDU,
updating the Next Pointer and the Previous Pointer with regard to each remaining element in the SIQ and the SSIQ, and
releasing the information element in the PIQ corresponding to the Sequence Number of the PDU for which the Transmission Complete Status is received.

13. The apparatus of claim 12,
wherein the circuitry is configured to control operation of:
(E) repeatedly performing (C) and (D), until a result of a determination after (D) is performed is all SDUs received are transmitted successfully.

14. An apparatus for processing a data packet received in a wireless communication system, the apparatus comprising:
circuitry configured to control operations of:
(A) when the data packet as a Protocol Data Unit (PDU) is successfully received at a wireless communication device of the system without retransmission,
determining whether another PDU with a same Sequence Number as a Sequence Number of the received PDU exists as an entry in a ReOrder Information Queue (ROIQ),
when the Sequence Number of the received PDU is determined to be the same as the Sequence Number of the another PDU, discarding the recently received PDU,
when the Sequence Number of the received PDU is determined not to be the same as the Sequence Number of the another PDU,
creating a new entry in the ROIQ for the received PDU, and
setting in the ROIQ:
a PDU Sequence Number to the Sequence Number of the received PDU,
a PDU Status to (i) complete PDU, when the received PDU is complete and (ii) PDU segment, when the received PDU is not complete,
a PDU Memory Address to a starting memory address of the received PDU stored in a system memory,
a Total Size to a size of the received PDU,
a Previous Pointer to an index of a previously received PDU in the ROIQ, and
a Next pointer to an index of a next free element in the ROIQ;



(B) repeatedly performing (A), until a PDU with any Sequence Number up to the Sequence Number of the received PDU is determined not to be missing, and
when a PDU with any sequence number up to the sequence number of the received PDU is determined not to be missing,
reordering each received PDU for reassembly into a reassembled SDU, and
setting in a ReAssembly Information Queue (RAIQ):
an Address to the system memory address of the received PDU,
a Segment Size to a size of a SDU or SDU segment in the received PDU, and
based on information in a header of the PDU received, a SDU Status to indicate one of (i) non-segmented (SDU_COMPLETE), (ii) segmented and first part of a parent SDU thereof (SDU_FIRST_SEG), (iii) segmented and last part of a parent SDU thereof (SDU_LAST_SEG), and (iv) segmented and an intermediate part of a parent SDU thereof (SDU_MIDDLE_SEG); and


(C) performing (A) and (B) repeatedly, until a result of a determination after (B) is performed is at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, and
when at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, delivering as the reassembled SDU a complete SDU to a predetermined layer of a protocol of the wireless communication system with, for each SDU segment in the complete SDU, information of a memory offset and size.

15. A wireless communication device comprising:
a transmitter to transmit a data packet in a wireless communication system; and
a processing device configured to control processing of the data packet for transmission in the wireless communication system,
wherein the processing device is 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; and


(B) when a transmission resource is determined to be allocated,
(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 PDIU 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.

16. The wireless communication device of claim 15,
wherein the processing device is configured to control repeatedly performing (A) and (B), until a result of a determination after (B) is performed is all new received SDUs in the SIQ have been transmitted as a given PDU.

17. The wireless communication device of claim 15, wherein the PDU includes one or more SDUs or SDU Segments.

18. The wireless communication device of claim 15,
wherein the processing device is configured to control operations of:
(C) when a Transmission Completion Status is received for a given PDU having a given Sequence Number,
searching the PIQ for an information element corresponding to the given Sequence Number,
based on a Pointer to the SSIQ of the information element determined from the searching the PIQ, identifying an associated information element in the SSIQ, and
from an SIQ Index of the associated information element in the SSIQ, identifying an information element in the SIQ to which the Transmission Completion Status corresponds; and

(D) performing (C) until a Transmission Completion Status for all SDU segments of a given SDU is received,
when the Transmission Completion status for all SDU segments of the given SDU is determined to be received,
releasing the information element in the SIQ corresponding to the given SDU and the information element in the SSQI corresponding to each SDU segment of the given SDU,
updating the Next Pointer and the Previous Pointer with regard to each remaining element in the SIQ and the SSIQ, and
releasing the information element in the PIQ corresponding to the Sequence Number of the PDU for which the Transmission Complete Status is received.

19. The wireless communication device of claim 18,
wherein the circuitry is configured to control operation of:
(E) repeatedly performing (C) and (D), until a result of a determination after (D) is performed is all SDUs received are transmitted successfully.

20. 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 the data packet as a Protocol Data Unit (PDU) is successfully received at the wireless communication device without retransmission,
determining whether another PDU with a same Sequence Number as a Sequence Number of the received PDU exists as an entry in a ReOrder Information Queue (ROIQ),
when the Sequence Number of the received PDU is determined to be the same as the Sequence Number of the another PDU, discarding the recently received PDU,
when the Sequence Number of the received PDU is determined not to be the same as the Sequence Number of the another PDU,
creating a new entry in the ROIQ for the received PDU, and
setting in the ROIQ:
a PDU Sequence Number to the Sequence Number of the received PDU,
a PDU Status to (i) complete PDU, when the received PDU is complete and (ii) PDU segment, when the received PDU is not complete,
a PDU Memory Address to a starting memory address of the received PDU stored in a system memory,
a Total Size to a size of the received PDU,
a Previous Pointer to an index of a previously received PDU in the ROIQ, and
a Next pointer to an index of a next free element in the ROIQ;



(B) repeatedly performing (A), until a PDU with any Sequence Number up to the Sequence Number of the received PDU is determined not to be missing, and
when a PDU with any sequence number up to the sequence number of the received PDU is determined not to be missing,
reordering each received PDU for reassembly into a reassembled SDU, and
setting in a ReAssembly Information Queue (RAIQ):
an Address to the system memory address of the received PDU,
a Segment Size to a size of a SDU or SDU segment in the received PDU, and
based on information in a header of the PDU received, a SDU Status to indicate one of (i) non-segmented (SDU_COMPLETE), (ii) segmented and first part of a parent SDU thereof (SDU_FIRST_SEG), (iii) segmented and last part of a parent SDU thereof (SDU_LAST_SEG), and (iv) segmented and an intermediate part of a parent SDU thereof (SDU_MIDDLE_SEG); and


(C) performing (A) and (B) repeatedly, until a result of a determination after (B) is performed is at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, and
when at least one element in the RAIQ has the SDU Status set to SDU_COMPLETE, delivering as the reassembled SDU a complete SDU to a predetermined layer of a protocol of the wireless communication system with, for each SDU segment in the complete SDU, information of a memory offset and size.