Abstract:
A network device and wireless transmit/receive unit (WTRU) using an enhanced high speed medium access control (MAC-ehs) are disclosed. A network device may provide a MAC-ehs reordering protocol data unit (PDU) with a segment of a service data unit (SDU). A MAC-ehs PDU is generated including the MAC-ehs reordering PDU. The MAC-ehs PDU is sent via a high speed downlink shared channel (HS-DSCH). The WTRU disassembles MAC-ehs PDUs to provide reordering PDUs that each may include a segment of a MAC-ehs SDU. The WTRU may reassemble a MAC-ehs SDU with the segment of the MAC-ehs SDU from at least one of the reordering PDUs.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/044,285 filed Mar. 7, 2008, which claims the benefit of U.S. provisional application No. 60/893,577 filed Mar. 7, 2007, the contents of which are hereby incorporated by reference herein. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention is related to wireless communications. 
       BACKGROUND 
       [0003]    High speed packet access (HSPA) evolution refers to the third generation partnership project (3GPP) radio access technology evolution of high speed downlink packet access (HSDPA) and high speed uplink packet access (HSUPA). Some of the major goals of HSPA evolution include higher data rates, higher system capacity and coverage, enhanced support for packet services, reduced latency, reduced operator costs and backward compatibility. 
         [0004]    It has been agreed that an enhanced high speed medium access control (MAC-ehs) entity is extended to include a function for segmentation and multiplexing from different priority queues in addition to being able to receive radio link control (RLC) protocol data units (PDUs) of flexible size. The addition of new MAC-hs functionalities requires modification to the conventional MAC-hs architecture. 
         [0005]      FIG. 1  shows a universal terrestrial radio access network (UTRAN) side MAC-ehs entity  100  proposed for HSPA evolution. In the proposed MAC-ehs architecture, segmentation is performed per logical channel by segmentation entities  112 . The segmented MAC-ehs service data units (SDUs) are then multiplexed by the logical channel identity (LCH-ID) multiplexing entities  114  based on the logical channel identity, and buffered in the configured priority queue  116 . A MAC-ehs protocol data unit (PDU) is then generated from the MAC-ehs SDUs stored in the priority queue  116  and transmitted via a hybrid automatic repeat request (HARQ) entity  120 . 
         [0006]      FIG. 2  shows a user equipment (UE) side MAC-ehs entity  200  proposed for HSPA evolution. The received MAC-ehs PDU via an HARQ entity  202  is disassembled into reordering PDUs by the disassembly entity  204 . The reordering PDUs are distributed to a reordering queue  208  by the reordering queue distribution entity  206  based on the received logical channel identifier. The reordering PDUs are reorganized according to the transmission sequence number (TSN). Reordering PDUs with consecutive TSNs are delivered to a higher layer upon reception. A timer mechanism determines delivery of non-consecutive data blocks to higher layers. There is one reordering entity  208  for each priority class. An LCH-ID demultiplexing entity  210  routes the reordered reordering PDUs to a reassembly entity  212  based on the logical channel identifier. The reassembly entity  212  reassembles segmented MAC-ehs SDUs to original MAC-ehs SDUs and forwards the MAC-ehs SDUs to upper layers. 
         [0007]    The proposed MAC-ehs entity  100  for the UTRAN-side performs segmentation on a per logical channel basis. However, the segmentation of the MAC-d PDUs should not be performed at that level, since the packet will not be transmitted immediately. The multiplexed reordering PDUs are buffered in the priority queue  116  and sent at a later time. Segmentation of the MAC-ehs SDUs prior to knowing the exact channel conditions is inefficient. The segmentation should not be performed prior to the time interval in which the packets will be transmitted. It would be desirable that the segmentation be performed at the time when the MAC-ehs PDU is created and the size of the transport block (TB) for that transmission time interval (TTI) is known. In addition, if the UTRAN is updated to segment the MAC-ehs SDUs right before the MAC-ehs SDUs are sent, the WTRU must also be updated accordingly. 
         [0008]    In the proposed MAC-ehs entity  200  in  FIG. 2 , the LCH-ID de-multiplexing entity  210  routes the MAC-ehs segments to the reassembly entity  212  based on the logical channel identity. This requires reassembly entities for different logical channels within the same queue. In addition, if MAC-ehs headers are optimized, the system information (SI) field will not be present for every logical channel, but it will be present only for the priority queue. 
       SUMMARY 
       [0009]    A method and apparatus for generating and processing a MAC-ehs PDU are disclosed. In a Node-B, MAC-ehs SDUs received from an upper layer are multiplexed based on a logical channel identity. Reordering PDUs are generated from the multiplexed MAC-ehs SDUs from different logical channels mapped to a priority queue. A reordering PDU includes at least one MAC-ehs SDU and/or at least one MAC-ehs SDU segment. A MAC-ehs SDU is segmented on a priority class basis if a MAC-ehs SDU does not fit into a reordering PDU. A MAC-ehs PDU is generated including at least one reordering PDU. The multiplexed MAC-ehs SDUs may be stored in a corresponding priority queue before generating the reordering PDUs. Alternatively, the reordering PDUs may be generated from the multiplexed MAC-ehs SDUs and the reordering PDUs may be stored in a corresponding priority queue. Alternatively, the received MAC-ehs SDUs may be buffered in a corresponding buffer for each logical channel before multiplexed based on a logical channel identity, or reordering PDUs are generated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    A more detailed understanding may be had from the following description, given by way of example and to be understood in conjunction with the accompanying drawings wherein: 
           [0011]      FIG. 1  shows a UTRAN-side MAC-ehs entity proposed for HSPA evolution; 
           [0012]      FIG. 2  shows a UE-side MAC-ehs entity proposed for HSPA evolution; 
           [0013]      FIGS. 3-4  show a UTRAN-side MAC-ehs entity in accordance with one embodiment; 
           [0014]      FIG. 5  shows a UTRAN-side MAC-ehs entity in accordance with another embodiment; 
           [0015]      FIGS. 6-8  show a UTRAN-side MAC-ehs entity in accordance with another embodiment; 
           [0016]      FIG. 9  shows a UTRAN-side MAC-ehs entity in accordance with another embodiment; and 
           [0017]      FIG. 10  shows a WTRU-side MAC-ehs entity in accordance with one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    When referred to hereafter, the terminology “wireless transmit/receive unit (WTRU)” includes but is not limited to a UE, a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a computer, or any other type of user device capable of operating in a wireless environment. When referred to hereafter, the terminology “Node-B” includes but is not limited to a base station, a site controller, an access point (AP), or any other type of interfacing device capable of operating in a wireless environment. 
         [0019]    The terminology “MAC-ehs payload unit” or “payload unit” will refer to a MAC-ehs SDU or a MAC-ehs SDU segment that is inserted as a payload of a MAC-ehs PDU. The terminology “MAC-d flow” and “logical channel” are used interchangeably, and use of one term does not exclude the other. The terminology “reordering PDU” refers to one unit of a MAC-ehs PDU. The MAC-ehs PDU may include one or more reordering PDUs. The reordering PDU may include one or more payload units. The MAC-ehs SDU may be a MAC-d PDU, MAC-c/sh/m PDU, or the like. 
         [0020]      FIG. 3  shows a UTRAN-side MAC-ehs entity  300  in accordance with one embodiment. The MAC-ehs entity  300  includes a scheduling and priority handling entity  310 , an HARQ entity  320 , and a transport format and resource combination (TFRC) selection entity  330 . The scheduling and priority handling entity  310  includes LCH-ID multiplexing entities  312 , priority queues  314 , segmentation entities  316 , and a priority queue multiplexing entity  318 . The scheduling and priority handling entity  310  manages HS-DSCH resources for data flows according to their priority class. The HARQ entity  320  handles HARQ functionality for supporting multiple instances (HARQ process) of stop and wait HARQ protocols. The TFRC selection entity  330  selects a TFRC. 
         [0021]    The MAC-ehs entity  300  receives MAC-ehs SDUs from an upper layer, (e.g., MAC-d or MAC-c entity (not shown)). The LCH-ID multiplexing entity  312  may multiplex the MAC-ehs SDUs from multiple logical channels based on the scheduling decision and the TFRC selected by the TFRC selection entity  330  The TFRC selection entity  330  indicates to the scheduling and priority handling entity  310  the size of the MAC-ehs PDU and thus the size of data to be transmitted from each queue into a reordering PDU to be transmitted on a TTI basis. The multiplexed MAC-ehs SDUs are stored in a priority queue  314 . 
         [0022]    The segmentation entity  316  may segment the MAC-ehs SDUs per priority queue. The segmentation entity  316  segments a MAC-ehs SDU if the MAC-ehs SDU does not fit into a reordering PDU. For example, if the MAC-ehs SDU to be included in the reordering PDU is greater than the size of the reordering PDU or it causes the sum of payload units to exceed the size of the selected reordering PDU, the segmentation entity  316  segments the MAC-ehs SDU. In this case, the reordering PDU includes only one segment of the MAC-ehs SDU. The remaining segment of the MAC-ehs SDU after segmentation is stored in the segmentation entity and may be transmitted as the first payload unit in the next reordering PDU for the priority queue if the remaining segment fits into the next reordering PDU. The remaining segment of the MAC-ehs SDU is segmented again if the remaining segment still does not fit into the next reordering PDU. This may be repeated until all the parts of the MAC-ehs SDU have been transmitted. The reordering PDU will contain at most two segments, one at the beginning and one at the end, and may include zero, one, or more than one complete MAC-ehs SDUs. 
         [0023]    The segmentation entity  316  may base its segmentation decision on the current channel condition, the given transport format and resource combination (TFRC) selection, the reordering PDU size, and the like. The segmentation is performed on a priority queue basis instead of on a per logical channel basis. 
         [0024]    The priority queue multiplexing entity  318  may perform multiplexing of reordering PDUs in one MAC-ehs PDU. The priority queue multiplexing entity  318  selects one or more reordering PDUs from one or more priority queues  316  in order to create the MAC-ehs PDU based on the TFRC selection. 
         [0025]    The priority queue multiplexing entity  318  may be incorporated into the HARQ entity  320 . The TFRC selection entity  330  may be attached to the scheduling and priority handling entity  310 , as shown in  FIG. 4 . 
         [0026]      FIG. 5  shows a UTRAN-side MAC-ehs entity  500  in accordance with another embodiment. In this embodiment, the segmentation is performed on a priority queue basis after logical channel multiplexing. The MAC-ehs entity  500  includes a scheduling and priority handling entity  510 , an HARQ entity  520 , and a TFRC selection entity  530 . The scheduling and priority handling entity  510  includes LCH-ID multiplexing entities  512 , segmentation entities  514 , priority queues  516 , and a priority queue multiplexing entity  518 . The scheduling and priority handling entity  510  manages HS-DSCH resources for data flows according to their priority class. The HARQ entity  520  handles HARQ functionality for supporting multiple instances (HARQ process) of stop and wait HARQ protocols. The TFRC selection entity  530  selects a TFRC. 
         [0027]    The MAC-ehs entity  500  receives MAC-ehs SDUs from an upper layer. The LCH-ID multiplexing entity  512  may multiplex MAC-ehs SDUs from multiple logical channels based on the scheduling decision and optionally based on the TFRC selected by the TFRC selection entity  530 . The TFRC selection entity  530  indicates to the scheduling and priority handling entity  510  the size of the MAC-ehs PDU to be transmitted on a TTI basis. 
         [0028]    The MAC-ehs SDUs, after the logical channel multiplexing, may be segmented by the segmentation entity  514 . The segmentation entity  514  segments a MAC-ehs SDU if the MAC-ehs SDU does not fit into a reordering PDU based on the TRFC selection. The reordering PDU contains at most two segments, one at the beginning and one at the end, and may include zero, one, or more than one MAC-ehs SDUs. 
         [0029]    Reordering PDUs are stored in a priority queue  516 . The priority queue multiplexing entity  518  may perform multiplexing of reordering PDUs in one MAC-ehs PDU. The priority queue multiplexing entity  518  selects one or more reordering PDUs from the priority queues  516  in order to create the MAC-ehs PDU. 
         [0030]    The priority queue multiplexing entity  518  may be incorporated into the HARQ entity  520 . The TFRC selection entity  530  may be attached to the scheduling and priority handling entity  510 . 
         [0031]      FIG. 6  shows a UTRAN-side MAC-ehs entity  600  in accordance with another embodiment. In this embodiment, the MAC-ehs SDUs are buffered per logical channel and segmentation is performed on a priority queue basis after logical channel multiplexing. The MAC-ehs entity  600  includes a scheduling and priority handling entity  610 , an HARQ entity  620 , and a TFRC selection entity  630 . The scheduling and priority handling entity  610  includes queues  612 , LCH-ID multiplexing entities  614 , segmentation entities  616 , priority handling entities  618 , and a priority queue multiplexing entity  619 . The scheduling and priority handling entity  610  manages HS-DSCH resources for data flows according to their priority class. The HARQ entity  620  handles HARQ functionality for supporting multiple instances (HARQ process) of stop and wait HARQ protocols. The TFRC selection entity  630  selects a TFRC. 
         [0032]    The MAC-ehs entity  600  receives MAC-ehs SDUs from upper layers. MAC-ehs SDUs are stored in queues  612  on a logical channel basis. Alternatively, the queues  612  may not be present and data from different logical channels may flow directly from upper layers to the corresponding LCH-ID multiplexing entities  614 . The LCH-ID multiplexing entities  614  multiplexes MAC-ehs SDUs stored in the queues  612  or received from the corresponding logical channels based on scheduling decision, scheduling priority and the TFRC selected by the TFRC selection entity  630 . Based on the TFRC selection and the selected reordering PDU size, the MAC-ehs SDUs may be segmented by the segmentation entity  616 . The segmentation entity  616  segments a MAC-ehs SDU if the MAC-ehs SDU does not fit into a reordering PDU. For example, if the MAC-ehs SDU to be included in the reordering PDU is greater than the size of the reordering PDU or it causes the sum of payload units to exceed the size of the reordering PDU, the segmentation entity  316  segments the MAC-ehs SDU. In this case, the reordering PDU includes only one segment of the MAC-ehs SDU. The remaining segment of the MAC-ehs SDU after segmentation is stored in the segmentation entity  616  and may be transmitted as the first payload unit in the next reordering PDU for the priority queue if the remaining segment fits into the next reordering PDU. The remaining segment of the MAC-ehs SDU is segmented again if the remaining segment still does not fit into the next reordering PDU. This may be repeated until all the parts of the MAC-ehs SDU have been transmitted. The reordering PDU contains at most two segments, one at the beginning and one at the end, and may include zero, one, or more than one MAC-ehs SDUs. 
         [0033]    The priority handling entity  618  defines relative priorities between sets of logical channels (and/or MAC-d flows), and optionally assigns TSNs. The priority queue multiplexing entity  619  performs multiplexing of reordering PDUs in one MAC-ehs PDU. 
         [0034]    The priority handling entity  618  and its functionalities may be incorporated in the priority queue multiplexing entity  619 , as shown in  FIG. 7 , (i.e., priority queue multiplexing and TSN setting entity  702 ). The segmentation entity  616  or the LCH-ID multiplexing entity  614  may be extended to buffer segments of the MAC-ehs SDUs. The TFRC selection entity  630  may be attached to the scheduling and priority handling entity  610 , as shown  FIG. 8 . 
         [0035]      FIG. 9  shows a UTRAN-side MAC-ehs entity  900  in accordance with another embodiment. In this embodiment, the MAC-ehs SDUs are buffered per logical channel. Alternatively, the queues  912  may not be present and data from different logical channels may flow directly from upper layers to the corresponding segmentation entities  914 . Segmentation is performed per logical channel on a TTI basis after the buffering. The MAC-ehs SDUs are buffered per logical channel rather than per priority queue. The MAC-ehs entity  900  includes a scheduling and priority handling entity  910 , an HARQ entity  920 , and a TFRC selection entity  930 . The scheduling and priority handling entity  910  includes queues  912 , segmentation entities  914 , LCH-ID multiplexing entities  916 , priority handling entities  918 , and a priority queue multiplexing entity  919 . The scheduling and priority handling entity  910  manages HS-DSCH resources for data flows according to their priority class. The HARQ entity  920  handles HARQ functionality for supporting multiple instances (HARQ process) of stop and wait HARQ protocols. The TFRC selection entity  930  selects a TFRC. 
         [0036]    The MAC-ehs entity  900  receives MAC-ehs SDUs from upper layers. MAC-ehs SDUs from logical channels, (or MAC-d flows), are stored in queues  912  for each logical channel or alternatively are directly delivered from upper layers without any buffering. The MAC-ehs SDUs may then be segmented by the segmentation entity  914 . The segmentation entity  914  segments a MAC-ehs SDU if the MAC-ehs SDU does not fit into a reordering PDU as selected by the TFRC selection. The reordering PDU contains at most two segments, one at the beginning and one at the end, and may include zero, one, or more than one MAC-ehs SDUs. The LCH-ID multiplexing entity  916  then multiplexes reordering PDUs from multiple logical channels, (i.e., multiple MAC-d flows), based on the scheduling decision and the TFRC selected by the TFRC selection entity  930 . 
         [0037]    The priority handling entity  918  defines relative priorities between sets of logical channels (and/or MAC-d flows), and optionally assigns TSNs. Alternatively, the TSNs setting may be performed per logical channel instead of per priority queue. The priority queue multiplexing entity  919  performs multiplexing of reordering PDUs in one MAC-ehs PDU. The priority handling entity and its functionality  918  may be incorporated in the priority queue multiplexing entity  919 . Alternatively, the LCH-ID MUX and priority queue multiplexing may be combined in one entity and multiplexing may be performed only on one level, on a logical channel basis. 
         [0038]    The segmentation entity  914  or the LCH-ID multiplexing entity  916  may be extended to buffer outstanding segments of the MAC-ehs SDUs. The TFRC selection entity  930  may be attached to the scheduling and priority handling entity  910 . 
         [0039]      FIG. 10  shows a WTRU-side MAC-ehs entity  1000  in accordance with one embodiment. Since in the UTRAN may perform segmentation after multiplexing logical channels in the mapped priority queue, the conventional WTRU-side MAC-ehs entity is modified to reflect these changes and to perform the reassembly and de-multiplexing in the same order. If segmentation is performed on a per priority queue basis, reassembly should be based on the reordering queue segmentation information. 
         [0040]    The MAC-ehs entity  1000  includes an HARQ entity  1002 , a disassembly entity  1004 , a reordering queue distribution entity  1006 , reordering queues  1008 , SDU disassembly entities  1010 , reassembly entities  1012 , and LCH-ID demultiplexing entities  1014 . The transmitted MAC-ehs PDUs are received via the HARQ entity  1002 . The disassembly entity  1004  disassembles the MAC-ehs PDU to reordering PDUs. The reordering queue distribution entity  1006  distributes the reordering PDUs to an appropriate reordering queue  1008  based on the logical channel identity. The reordering PDUs are reordered at the reordering queue  1008  based on the TSN. The SDU disassembly entity  1010  disassembles MAC-ehs SDUs and segmented MAC-ehs SDUs from the reordered reordering PDUs, and delivers them to the reassembly entity  1012 . The reassembly entity  1012  reassembles segmented MAC-ehs SDUs to original MAC-ehs SDUs for every reordering PDU and forwards the completed and reassembled MAC-ehs SDUs to the LCH-ID demultiplexing entity  1014 . The LCH-ID demultiplexing entity  1014  routes the complete MAC-ehs SDUs to the correct logical channel, or MAC-d flow. Optionally, the SDU disassembly entity  1010  and the reassembly entity  1012  may be combined to one entity. 
         [0041]    Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). 
         [0042]    Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine. 
         [0043]    A processor in association with software may be used to implement a radio frequency transceiver for use in a wireless transmit receive unit (WTRU), user equipment (UE), terminal, base station, radio network controller (RNC), or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a Bluetooth® module, a frequency modulated (FM) radio unit, a liquid crystal display (LCD) display unit, an organic light-emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an Internet browser, and/or any wireless local area network (WLAN) module.