Abstract:
Embodiments of the present disclosure describe devices, methods, computer-readable media and systems configurations for determining a hybrid automatic repeat request (HARQ)-acknowledgment (ACK) codebook in wireless communication networks.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority to U.S. Provisional Patent Application No. 61/612,188, filed Mar. 16, 2012, entitled “WIRELESS COMMUNICATION SYSTEMS AND METHODS,” the entire disclosure of which is hereby incorporated by reference. 
     
    
     FIELD 
       [0002]    Embodiments of the present invention relate generally to the field of communications, and more particularly, to determining size of a hybrid automatic repeat request-acknowledgment (HARQ-ACK) codebook in wireless communication networks. 
       BACKGROUND 
       [0003]    Release 8 of the Third Generation Partnership Project (3GPP) Long-Term Evolution (LTE) standard describes piggybacking uplink control information (UCI) on a physical uplink shared channel (PUSCH). The channel quality indicator/pre-coding matrix indicator (CQI/PMI) resources are placed at the beginning of uplink shared channel (UL-SCH) data resources and mapped sequentially to all single-carrier frequency division multiple access (SC-FDMA) symbols on one subcarrier before continuing on the next subcarrier. The UL-SCH data is rate-matched around the CQI/PMI data. The HARQ-ACK resources are mapped to SC-FDMA symbols by puncturing the PUSCH data resource elements (REs). Reducing the PUSCH REs punctured by the HARQ-ACK symbols would, therefore, improve the PUSCH performance. 
         [0004]    In light of the above, Release 8 provides a 2-bit downlink assignment Index (DAI) in downlink control information (DCI) format 0/4, V DAI   UL , which is used to indicate total number of downlink (DL) assignments in a bundling window. Assuming the bundling window size is M, only V DAI   UL  HARQ-ACK bits, rather than M bits, need to be fed back to a transmitting device, e.g., an enhanced node base station (eNB), if PUSCH transmission is adjusted based on a detected PDCCH with DCI format 0/4. Thus, (M−V DAI   UL ) useless HARQ-ACK bits, corresponding to DL subframes that were not scheduled by the eNB, are reduced. 
         [0005]    Release 10 of the LTE standard (Rel-10) introduces carrier aggregation, in which more than one component carrier (CC) may be used for data transmissions. In a Release 10 time division duplexing (TDD) system, the HARQ-ACK codebook size, in case of piggybacking on PUSCH, is determined by the number of CCs, their configured transmission mode, and number of downlink subframes in bundled window. For TDD UL-DL configurations 1-6, and when PUCCH format 3 is configured for transmission of HARQ-ACK, the HARQ-ACK codebook size is determined by: 
         [0000]        n   HARQ   =B   c   DL ( C+c   2 ),  (1)
 
         [0006]    where C is the number of configured CCs, C 2  is the number of CCs configured with a multiple-input, multiple-output (MIMO) transmission mode that enables reception of two transport blocks; B c   DL  is the number of downlink subframes for which UE needs to feedback HARQ-ACK bits for the c th  serving cell. For TDD UL-DL configuration 1, 2, 3, 4, and 6, the UEs will assume B c   DL  on PUSCH subframe n as: 
         [0000]      B c   DL =W DAI   UL ,  (2)
 
         [0007]    where W DAI   UL  is determined by the DAI in DCI format 0/4 according to the following table: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 DAI 
                   
               
               
                   
                 MSB, LSB 
                 W DAI   UL   
               
               
                   
                   
               
             
             
               
                   
                 0, 0 
                 1 
               
               
                   
                 0, 1 
                 2 
               
               
                   
                 1, 0 
                 3 
               
               
                   
                 1, 1 
                 4 
               
               
                   
                   
               
             
          
         
       
     
         [0008]    The DAI may be communicated in a subframe that has a predetermined association with subframe n for each serving cell. For example, the DAI may be communicated in subframe n−k′, where k′ is defined in the following table: 
         [0000]    
       
         
               
               
             
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 TDD UL/DL 
                 subframe number n 
               
             
          
           
               
                 Configuration 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 1 
                   
                   
                 6 
                 4 
                   
                   
                   
                 6 
                 4 
                   
               
               
                 2 
                   
                   
                 4 
                   
                   
                   
                   
                 4 
               
               
                 3 
                   
                   
                 4 
                 4 
                 4 
               
               
                 4 
                   
                   
                 4 
                 4 
               
               
                 5 
                   
                   
                 4 
               
               
                 6 
                   
                   
                 7 
                 7 
                 5 
                   
                   
                 7 
                 7 
               
               
                   
               
             
          
         
       
     
         [0009]    Since the TDD UL-DL configuration of each serving cell is always identical in Rel-10 and W DAI   UL  is definitely no larger than the bundling window size, the HARQ-ACK codebook size determined by W DAI   UL  is always equal to minimum HARQ-ACK bits number and is the best tradeoff between HARQ-ACK overhead and performance. 
         [0010]    In Release 11 of the 3GPP LTE standard, interband CA of TDD with CCs having different UL-DL configurations for each serving cell is supported. Having different UL-DL configurations in the different serving cells may result in different HARQ-ACK bundling windows. Therefore, the UL grant based HARQ-ACK codebook size determination in previous releases may not effectively reduce the HARQ-ACK overhead. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings. 
           [0012]      FIG. 1  schematically illustrates a wireless communication network in accordance with various embodiments. 
           [0013]      FIG. 2  illustrates an example TDD communication structure with HARQ-ACK timing information in accordance with various embodiments. 
           [0014]      FIG. 3  is a flowchart illustrating a method of determining a HARQ-ACK codebook size that may be performed by a user equipment in accordance with various embodiments. 
           [0015]      FIG. 4  is a HARQ-ACK bits generation table in accordance with some embodiments. 
           [0016]      FIG. 5  schematically depicts an example system in accordance with various embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Illustrative embodiments of the present disclosure include, but are not limited to, methods, systems, computer-readable media, and apparatuses for determining a size of a HARQ-ACK codebook in wireless communication networks. Various embodiments may provide user equipment (UE) that operate in conformance with Release 11 of 3GPP LTE (hereinafter “Rel-11”) (and later releases) with the ability to determine HARQ-ACK codebook size on PUSCH in a manner to reduce HARQ-ACK overhead while maintaining HARQ-ACK performance for interband CA of TDD CCs with different UL-DL configurations for different serving cells. In this manner, described UEs may adaptively determine the desired HARQ-ACK codebook size to puncture the PUSCH REs that will reduce negative impact on the PUSCH with little to no additional overhead. 
         [0018]    Various embodiments may be described with reference to specific configurations, e.g., TDD UL-DL configurations and special subframe configurations; formats, e.g., DCI formats; modes, e.g., transmission modes; etc. These configurations, formats, modes, etc., may be defined consistent with presently published LTE documents, e.g., Rel-10 and/or Rel-11 technical specifications. 
         [0019]    Various aspects of the illustrative embodiments will be described using terms commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. However, it will be apparent to those skilled in the art that alternate embodiments may be practiced with only some of the described aspects. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. However, it will be apparent to one skilled in the art that alternate embodiments may be practiced without the specific details. In other instances, well-known features are omitted or simplified in order not to obscure the illustrative embodiments. 
         [0020]    Further, various operations will be described as multiple discrete operations, in turn, in a manner that is most helpful in understanding the illustrative embodiments; however, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation. 
         [0021]    The phrase “in some embodiments” is used repeatedly. The phrase generally does not refer to the same embodiments; however, it may. The terms “comprising,” “having,” and “including” are synonymous, unless the context dictates otherwise. The phrase “A and/or B” means (A), (B), or (A and B). The phrase “A/B” means (A), (B), or (A and B), similar to the phrase “A and/or B”. The phrase “at least one of A, B and C” means (A), (B), (C), (A and B), (A and C), (B and C) or (A, B and C). The phrase “(A) B” means (B) or (A and B), that is, A is optional. 
         [0022]    Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described, without departing from the scope of the embodiments of the present disclosure. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that the embodiments of the present disclosure be limited only by the claims and the equivalents thereof. 
         [0023]    As used herein, the term “module” may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group), combinational logic circuit, or other electronic circuit that provides the described functionality. In various embodiments, the module may execute instructions stored in one or more computer-readable media to provide the described functionality. 
         [0024]      FIG. 1  schematically illustrates a wireless communication network  100  in accordance with various embodiments. Wireless communication network  100  (hereinafter “network  100 ”) may be an access network of a 3GPP LTE network such as evolved universal terrestrial radio access network (E-UTRAN). The network  100  may include a base station, e.g., enhanced node base station (eNB)  104 , configured to wirelessly communicate with user equipment (UE)  108 . 
         [0025]    As shown in  FIG. 1 , the UE  108  may include feedback controller  112  coupled with transceiver module  116 . The transceiver module  116  may be further coupled with one or more of a plurality of antennas  132  of the UE  108  for communicating wirelessly with other components of the network  100 , e.g., eNB  104 . 
         [0026]    In some embodiments, the UE  108  may be capable of utilizing carrier aggregation (CA) in which a number of component carriers (CCs) are aggregated for communication between the eNB  104  and the UE  108 . The transceiver module  116  may be configured to communicate with the eNB  104  via a plurality of serving cells utilizing a respective plurality of CCs. The CCs may be disposed in different bands and may be associated with different TDD UL-DL configurations (hereinafter also referred to as “UL-DL configurations”). Thus, in some embodiments, at least two serving cells may have different UL-DL configurations. 
         [0027]    Table 3 below shows example UL-DL configurations that may be employed in various embodiments of the present invention. 
         [0000]    
       
         
               
               
             
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 TDD UL-DL 
                 Subframe number 
               
             
          
           
               
                 configuration 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 0 
                 D 
                 S 
                 U 
                 U 
                 U 
                 D 
                 S 
                 U 
                 U 
                 U 
               
               
                 1 
                 D 
                 S 
                 U 
                 U 
                 D 
                 D 
                 S 
                 U 
                 U 
                 D 
               
               
                 2 
                 D 
                 S 
                 U 
                 D 
                 D 
                 D 
                 S 
                 U 
                 D 
                 D 
               
               
                 3 
                 D 
                 S 
                 U 
                 U 
                 U 
                 D 
                 D 
                 D 
                 D 
                 D 
               
               
                 4 
                 D 
                 S 
                 U 
                 U 
                 D 
                 D 
                 D 
                 D 
                 D 
                 D 
               
               
                 5 
                 D 
                 S 
                 U 
                 D 
                 D 
                 D 
                 D 
                 D 
                 D 
                 D 
               
               
                 6 
                 D 
                 S 
                 U 
                 U 
                 U 
                 D 
                 S 
                 U 
                 U 
                 D 
               
               
                   
               
             
          
         
       
     
         [0028]    In Table 3, D is a subframe for a downlink transmission, U is a subframe for an uplink transmission, and S is a special subframe used, e.g., for a guard time. In some embodiments, a special subframe may include three fields: downlink pilot time slot (DwPTS), which may include the DCI, guard period (GP), and uplink pilot time slot (UpPTS) 
         [0029]    In an initial connection establishment, the UE  108  may connect with a primary serving cell (PCe11) of the eNB  104  utilizing a primary CC, which may also be referred to as CC 0 . This connection may be used for various functions such as security, mobility, configuration, etc. Subsequently, the UE  108  may connect with one or more secondary serving cells (SCells) of the eNB  104  utilizing one or more secondary CCs. These connections may be used to provide additional radio resources. 
         [0030]      FIG. 2  illustrates an example TDD communication structure  200  with HARQ-ACK timing information in accordance with an embodiment. In the TDD communication structure  200 , three serving cells may be configured for communication between the eNB  104  and the UE  108 . For example, a PCell having UL-DL configuration  0 , an SCell  1  having UL-DL configuration  2 , and an SCell  2  having UL-DL configuration  1 . In other embodiments, other number of serving cells may be configured for communication between the eNB  104  and the UE  108 . 
         [0031]    In the TDD communication structure  200 , the PCell may have a bundling window, M 0 , that includes one subframe that may include downlink transmissions, e.g., PDSCH transmissions or PDCCH transmissions indicating downlink semi-persistent scheduling (SPS) release, for which corresponding HARQ-ACK information is to be transmitted as a PUSCH transmission in an associated uplink subframe, e.g., subframe  7  of the SCell  1 . The SCell  1  may have a bundling window, M I , that includes four subframes that may include downlink transmissions for which corresponding HARQ-ACK information is to be transmitted as a PUSCH transmission in an associated uplink subframe, e.g., subframe  7  of the SCell  1 . The SCell  2  may have a bundling window, M 2 , that includes two subframes that may include downlink transmissions for which corresponding HARQ-ACK information is to be transmitted as a PUSCH transmission in an associated uplink subframe, e.g., subframe  7  of the SCell  1 . The association between the DL subframes of the respective bundling windows and the UL subframe that will be used to transmit the corresponding HARQ-ACK information may be based on a predetermined HARQ timing reference. An example of such HARQ timing references is shown and discussed below with respect to Table 4. 
         [0032]    In the example shown in  FIG. 2 , all of the subframes capable of carrying downlink transmissions for which corresponding HARQ-ACK information is to be transmitted are shown as having PDSCH transmissions. However, in other embodiments, the eNB may not schedule downlink transmissions on one or more of these subframes. 
         [0033]      FIG. 3  illustrates a method  300  of determining a HARQ-ACK codebook size in accordance with some embodiments. Method  300  may be performed by a feedback controller of a UE, e.g., feedback controller  112  of UE  108 . In some embodiments, the UE may include and/or have access to one or more computer-readable media having instructions stored thereon, that, when executed, cause the UE, or feedback controller, to perform the method  300 . 
         [0034]    At  304 , the feedback controller may determine the HARQ-ACK timing and bundling window for each configured serving cell. In some embodiments, the feedback controller may determine, for each configured serving cell, a total number of subframes within a bundling window that is associated with an uplink subframe. In general, the HARQ-ACK bundling window may include both downlink subframes and special subframes, as both are capable of carrying PDSCH transmissions. However, in some embodiments, certain special subframes may be excluded from the bundling window in order to reduce HARQ-ACK codebook size. For example, in special subframes of configurations  0  and  5  with normal downlink cyclic prefix (CP) or configurations  0  and  4  with extended downlink CP may be excluded from the bundling window as they typically do not carry PDSCH transmissions. The special subframe configurations may be defined consistent with Table 4.2-1 of 3GPP Technical Specification (TS) 36.211 V 10.5.0 (2012-06). 
         [0035]    In some embodiments, the HARQ-ACK timing and bundling windows, M c , may be determined according to a predetermined downlink association set index K: {k 0 , k 1 , . . . k M-I } for TDD as illustrated in the UL-DL configurations for HARQ timing reference of Table 4. 
         [0000]    
       
         
               
               
             
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 UL-DL 
                 Subframe n 
               
             
          
           
               
                 Configuration 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 0 
                 — 
                 — 
                 6 
                 — 
                 4 
                 — 
                 — 
                 6 
                 — 
                 4 
               
               
                 1 
                 — 
                 — 
                 7, 6 
                 4 
                 — 
                 — 
                 — 
                 7, 6 
                 4 
                 — 
               
               
                 2 
                 — 
                 — 
                 8, 7, 4, 6 
                 — 
                 — 
                 — 
                 — 
                 8, 7, 4, 6 
                 — 
                 — 
               
               
                 3 
                 — 
                 — 
                 7, 6, 11 
                 6, 5 
                 5, 4 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 4 
                 — 
                 — 
                 12, 8, 7, 11 
                 6, 5, 4, 7 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 5 
                 — 
                 — 
                 13, 12, 9, 8, 7, 5, 4, 11, 6 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
                 — 
               
               
                 6 
                 — 
                 — 
                 7 
                 7 
                 5 
                 — 
                 — 
                 7 
                 7 
                 — 
               
               
                   
               
             
          
         
       
     
         [0036]    In various embodiments, each serving cell may have a HARQ timing reference that is the same or different from the UL-DL configuration of the serving cell. The UL-DL configuration of the serving cell is communicated in the serving cell&#39;s System Information Block (SIB)  1  and, therefore, may also be referred to as the serving cell&#39;s SIB 1  configuration. The HARQ timing reference of a PCell may be the same as the PCell&#39;s SIB 1  configuration, while a HARQ timing reference of an SCell may be selected by considering both the SCell&#39;s SIB  1  configuration and the PCell&#39;s SIB 1  configuration according to Table 5. 
         [0000]    
       
         
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 UL-DL configuration 
                   
               
               
                 for HARQ timing 
                 SCell SIB1 UL-DL configuration 
               
             
          
           
               
                 reference 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
               
               
                   
               
             
          
           
               
                 PCell SIB1 
                 0 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
               
               
                 UL-DL 
                 1 
                 1 
                 1 
                 2 
                 4 
                 4 
                 5 
                 1 
               
               
                 configuration 
                 2 
                 2 
                 2 
                 2 
                 5 
                 5 
                 5 
                 2 
               
               
                   
                 3 
                 3 
                 4 
                 5 
                 3 
                 4 
                 5 
                 3 
               
               
                   
                 4 
                 4 
                 4 
                 5 
                 4 
                 4 
                 5 
                 4 
               
               
                   
                 5 
                 5 
                 5 
                 5 
                 5 
                 5 
                 5 
                 5 
               
               
                   
                 6 
                 6 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
               
               
                   
               
             
          
         
       
     
         [0037]    According to Table 5, and with reference to  FIG. 2 , the PCell will use UL-DL configuration  0  for its HARQ timing reference, SCell  1  will use UL-DL configuration  2  for its HARQ timing reference, and SCell will use UL-DL configuration  1  for its HARQ timing reference. While this embodiment illustrates both SCells using their SIB 1  configurations for HARQ timing reference, an SCell may use other UL-DL configurations for its HARQ timing reference in other embodiments. For example, if SCell  1  had a SIB 1  configuration of  3  and the PCell had a SIB 1  configuration of  1 , the SCell would use UL-DL configuration  4  for its HARQ timing reference. 
         [0038]    To further illustrate use of Tables 4 and 5, consider the following. With subframe  7  (e.g., n=7) of the SCell  1  being designated as the uplink subframe for transmitting HARQ-ACK information, the associated downlink subframes may be determined by n−k, where k ∈ K. The size of the bundling window, M c , is the cardinality of the set K of elements, and the specific subframes of the bundling window are determined by n−k 0 , . . . n−k M-1 . So, the size of the bundling window of the PCell, M 0 , is 1 (given that only one element is associated with UL-DL configuration  0 , subframe n=7 in Table 4), and the downlink subframe of M 0  is 7−6=1, e.g., DL subframe  1 . The size of the bundling window of SCell  1 , M 1 , is 4 (given four elements of Table 4) and the DL subframes of M 1  are subframe  3  ( 7 - 4 ), subframe  1  ( 7 - 6 ), subframe  0  ( 7 - 7 ), and subframe  9  of previous frame ( 7 - 8 ). The size of the bundling window of SCell  2 , M 2 , is 2 (given two elements of Table 4) and the DL subframes of M 2  are subframe  0  ( 7 - 7 ) and subframe  1  ( 7 - 6 ). 
         [0039]    At 308, the feedback controller may determine a DAI. The DAI may be communicated in a subframe that has a predetermined association with the uplink subframe, n, that will carry the HARQ-ACK information for the bundling windows, e.g., subframe  7  in SCell  1 . In some embodiments, the DAI may be communicated in subframe n−k′, where k′ is defined in Table 2. In some embodiments, the DAI may be used to determine W DAI   UL  according to Table 1. W DAI   UL  may correspond to a maximum value of number of scheduled downlink subframes within bundling windows of the plurality of serving cells. With reference to  FIG. 2 , W DAI   UL =4 because 4 downlink subframes are scheduled in SCell  1 . 
         [0040]    At  312 , the feedback controller may determine a number of HARQ-ACK bits, which correspond to the configured serving cells, on a PUSCH of the uplink subframe. In some embodiments, the feedback controller may determine the number of HARQ-ACK bits, for each serving cell, based on the W DAI   UL , which is based on the DAI for uplink resource allocation, and the number of subframes of the bundling window of the corresponding serving cell according to the HARQ timing reference configuration. 
         [0041]    In some embodiments, the number of HARQ-ACK bits for the c th  serving cell, O c , may be determined by the following equation. 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       O 
                       c 
                     
                     = 
                     
                       
                         Min 
                         ( 
                         
                           
                             M 
                             c 
                             DL 
                           
                           , 
                           
                             
                               W 
                               DAI 
                               UL 
                             
                             + 
                             
                               4 
                                
                               
                                 ⌈ 
                                 
                                   
                                     ( 
                                     
                                       U 
                                       - 
                                       
                                         W 
                                         DAI 
                                         UL 
                                       
                                     
                                     ) 
                                   
                                   4 
                                 
                                 ⌉ 
                               
                             
                           
                         
                         ) 
                       
                       * 
                       
                         C 
                         c 
                         DL 
                       
                     
                   
                   , 
                 
               
               
                 
                   Equation 
                    
                   
                       
                   
                    
                   1 
                 
               
             
           
         
       
     
         [0042]    where U is a maximum value of U c  among all configured serving cells, U c  is the total number of subframes with received transmissions (e.g., PDSCHs and PDCCHs indicating downlink SPS release) in bundling window (e.g., subframe(s) n−k where k ∈ K as described with respect to Table 4) of the c th  serving cell, W DAI   UL  is determined by the DAI included in DCI, which may have format 0 or 4, that allocates uplink transmission resource of the serving cell in which the UCI piggybacking on the PUSCH (e.g., SCell  1 ) according to Table 1 in subframe n-k′, where k′ is defined in Table 2; C c   DL =1 if transmission mode configured in the c th  serving cell supports one transport block and C c   DL =2 otherwise; and Min(X,Y)=X if X≦Y, and Min(X,Y)=Y otherwise. 
         [0043]    In embodiments in which none of the plurality of aggregated serving cells include a configuration  5  as a HARQ timing reference configuration, W DAI   UL  will be at least as large as U, thereby canceling out the 
         [0000]    
       
         
           
             4 
              
             
               ⌈ 
               
                 
                   ( 
                   
                     U 
                     - 
                     
                       W 
                       DAI 
                       UL 
                     
                   
                   ) 
                 
                 4 
               
               ⌉ 
             
           
         
       
     
         [0000]    term of Equation 1. Thus, Equation 1 is reduced to: 
         [0000]        O   c =Min ( M   c   DL   ,W   DAI   UL )* C   c   DL .  Equation 2
 
         [0044]    Thus, in some embodiments, Equation 2 will be used for HARQ-ACK transmission in an UL subframe n and on the PUSCH adjusted by its associated UL grant with W DAI   UL  if none of the HARQ timing reference configurations of the aggregated serving cells is configuration  5 , and Equation 1 will be used for HARQ-ACK transmission in an UL subframe n and on the PUSCH adjusted by its associated UL grant with W DAI   UL  if the HARQ timing reference configuration of any of the aggregated serving cells is configuration  5 . 
         [0045]    It may be noted that in some embodiments, neither Equation 1 or 2 may be used in situations in which the serving cell that performs the PUSCH scheduling (e.g., SCell  1  in  FIG. 2 ) has a SIB 1  configuration  0 . In these embodiments, the eNB may not be able to transmit DAI in DCI format 0/4 and, therefore, the UE will not be able to determine W. 
         [0046]    The HARQ-ACK feedback bits O c,0   ACK , O c,1   ACK , . . . O c,0     c     ACK  for the c th  serving cell are constructed as follows, where c≧0: the HARQ-ACK for a PDSCH transmission associated with a DCI message of a PDDCH or a PDCCH transmission indicating downlink SPS release in subframe n−k is associated with O c,DAI(k)−1   ACK  if transmission mode configured in the c th  serving cell supports one transport block, or associated with O c,DAI(k)−2   ACK  and O c,DAI(k)−1   ACK  otherwise, where DAI(k) is the value of DAI, for resource allocation of downlink subframe, in DCI format 1A/1B/1D/½2A/2B/2C detected in subframe n−k depending on the bundling window in the c th  serving cell. The HARQ-ACK feedback bits without any detected PDSCH transmission or without detected PDCCH indicating downlink SPS release may be set to NACK. 
         [0047]    An example is provided below, with reference to  FIG. 2  and assuming transmission mode  4  with two transport blocks enabled is configured. The special subframe configuration of each CC is configuration 3 with normal downlink cyclic prefix (CP). As stated above, the eNB, in this example, may transmit at each opportunity within the designated bundling windows, e.g., subframe  1  of PCell, subframes  9 ,  0 ,  1 , and  3  of SCell  1 , and subframes  0  and  1  of SCell  2 . Further, the UE may receive, in subframe  3  of the SCell  1 , the uplink grant for the PUSCH transmission at subframe  7  of the SCell  1 . Since the maximum value of total number of PDSCH scheduled subframes within the bundling windows is 4 according to present assumptions, the W DAI   UL  of uplink grant for subframe  7  shall be set as 4 by the eNB. According to Equation 1, the O 0  value of HARQ-ACK bits for PCell may be calculated as follows 
         [0000]    
       
         
           
             
               O 
               0 
             
             = 
             
               
                 
                   Min 
                   ( 
                   
                     1 
                     , 
                     
                       4 
                       + 
                       
                         4 
                          
                         
                           ⌈ 
                           
                             
                               ( 
                               
                                 4 
                                 - 
                                 4 
                               
                               ) 
                             
                             4 
                           
                           ⌉ 
                         
                       
                     
                   
                   ) 
                 
                 * 
                 2 
               
               = 
               2. 
             
           
         
       
     
         [0048]    In the same manner, the HARQ-ACK bits for SCell  1  and SCell  2  may be determined as O 1 =8 and O 2 =4, respectively. This is shown, graphically, in HARQ-ACK bits generation table  400  of  FIG. 4  in accordance with some embodiments. Were the HARQ-ACK bits determined according to the Rel-10 methodology, the results would be O 0   =8, O   1 =8 and O 2 =8. 
         [0049]    At  316 , the feedback controller may determine the HARQ-ACK codebook size on the PUSCH of the uplink subframe. The determination of the HARQ-ACK codebook size may be done by aggregating the number of HARQ-ACK bits that corresponds to each of the plurality of serving cells according to the following equation, 
         [0000]    
       
         
           
             
               
                 
                   O 
                   = 
                   
                     
                       ∑ 
                       
                         c 
                         = 
                         0 
                       
                       
                         
                           N 
                           Cells 
                           DL 
                         
                         - 
                         1 
                       
                     
                      
                     
                       
                         O 
                         c 
                       
                       . 
                     
                   
                 
               
               
                 
                   Equation 
                    
                   
                       
                   
                    
                   2 
                 
               
             
           
         
       
     
         [0050]    In the above discussed example, O=14. In the Rel-10 methodology, O=24. Thus, the described embodiments result in a 42% reduction in HARQ-ACK overhead. In this manner, the PUSCH performance and system throughput may be improved without impacting HARQ-ACK performance. 
         [0051]    The UE  108  described herein may be implemented into a system using any suitable hardware and/or software to configure as desired.  FIG. 5  illustrates, for one embodiment, an example system  500  comprising one or more processor(s)  504 , system control logic  508  coupled with at least one of the processor(s)  504 , system memory  512  coupled with system control logic  508 , non-volatile memory (NVM)/storage  516  coupled with system control logic  508 , a network interface  520  coupled with system control logic  508 , and input/output (I/O) devices  532  coupled with system control logic  508 . 
         [0052]    The processor(s)  504  may include one or more single-core or multi-core processors. The processor(s)  504  may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, baseband processors, etc.). 
         [0053]    System control logic  508  for one embodiment may include any suitable interface controllers to provide for any suitable interface to at least one of the processor(s)  504  and/or to any suitable device or component in communication with system control logic  508 . 
         [0054]    System control logic  508  for one embodiment may include one or more memory controller(s) to provide an interface to system memory  512 . System memory  512  may be used to load and store data and/or instructions for system  500 . In some embodiments, the system memory  512  may include HARQ logic  524  that, when executed, cause a feedback controller to perform the various operations described herein. System memory  512  for one embodiment may include any suitable volatile memory, such as suitable dynamic random access memory (DRAM), for example. 
         [0055]    NVM/storage  516  may include one or more tangible, non-transitory computer-readable media used to store data and/or instructions, for example, HARQ logic  524 . NVM/storage  516  may include any suitable non-volatile memory, such as flash memory, for example, and/or may include any suitable non-volatile storage device(s), such as one or more hard disk drive(s) (HDD(s)), one or more compact disk (CD) drive(s), and/or one or more digital versatile disk (DVD) drive(s), for example. 
         [0056]    The NVM/storage  516  may include a storage resource physically part of a device on which the system  500  is installed or it may be accessible by, but not necessarily a part of, the device. For example, the NVM/storage  516  may be accessed over a network via the network interface  520  and/or over Input/Output (I/O) devices  532 . 
         [0057]    Network interface  520  may have a transceiver module  522 , similar to transceiver module  116 , to provide a radio interface for system  500  to communicate over one or more network(s) and/or with any other suitable device. In various embodiments, the transceiver module  522  may be integrated with other components of system  500 . For example, the transceiver module  522  may include a processor of the processor(s)  504 , memory of the system memory  512 , and NVM/Storage of NVM/Storage  516 . Network interface  520  may include any suitable hardware and/or firmware. Network interface  520  may include a plurality of antennas to provide a multiple input, multiple output radio interface. Network interface  520  for one embodiment may include, for example, a wired network adapter, a wireless network adapter, a telephone modem, and/or a wireless modem. 
         [0058]    For one embodiment, at least one of the processor(s)  504  may be packaged together with logic for one or more controller(s) of system control logic  508 . For one embodiment, at least one of the processor(s)  504  may be packaged together with logic for one or more controllers of system control logic  508  to form a System in Package (SiP). For one embodiment, at least one of the processor(s)  504  may be integrated on the same die with logic for one or more controller(s) of system control logic  508 . For one embodiment, at least one of the processor(s)  504  may be integrated on the same die with logic for one or more controller(s) of system control logic  508  to form a System on Chip (SoC). 
         [0059]    In various embodiments, the I/O devices  532  may include user interfaces designed to enable user interaction with the system  500 , peripheral component interfaces designed to enable peripheral component interaction with the system  500 , and/or sensors designed to determine environmental conditions and/or location information related to the system  500 . 
         [0060]    In various embodiments, the user interfaces could include, but are not limited to, a display (e.g., a liquid crystal display, a touch screen display, etc.), a speaker, a microphone, one or more cameras (e.g., a still camera and/or a video camera), a flashlight (e.g., a light emitting diode flash), and a keyboard. 
         [0061]    In various embodiments, the peripheral component interfaces may include, but are not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, and a power supply interface. 
         [0062]    In various embodiments, the sensors may include, but are not limited to, a gyro sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of, or interact with, the network interface  520  to communicate with components of a positioning network, e.g., a global positioning system (GPS) satellite. 
         [0063]    In various embodiments, the system  500  may be an eNB or a mobile computing device such as, but not limited to, a laptop computing device, a tablet computing device, a netbook, a smartphone, etc. In various embodiments, system  500  may have more or less components, and/or different architectures. 
         [0064]    Although certain embodiments have been illustrated and described herein for purposes of description, a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments described herein be limited only by the claims and the equivalents thereof