Abstract:
This application considers the need for enhancements to the baseline CSI reporting mechanisms including maximum payload size, CQI/PMI reporting configurations and CSI transmission in the event of collision between CSI reports from different CCs.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The technical field of this invention is wireless communication such as wireless telephony. 
       BACKGROUND OF THE INVENTION 
       [0002]    The 3GPP Release 10 specification introduced the carrier aggregation feature, wherein user equipment (UE) may be configured to simultaneously receive or transmit data on multiple component carriers (CCs). Each component carrier (CC) is also called a serving cell. The serving cell where the UE maintains a Radio Resource Control connection to the network is known as the primary cell or the primary component carrier. Additional component carriers can be configured for a UE for data transmission and reception, and these carriers are known as secondary component carriers or secondary serving cells. Throughout this application the terms primary component carrier (PCC) and primary serving cell (PCell) are used interchangeably. Similarly, the terms secondary component carrier (SCC) or secondary serving cell (SCell) are used interchangeably. 
         [0003]    For carrier aggregation when Channel State Information (CSI) reports for multiple carriers collide in time, only one CQI is reported while the CSI for other carriers are dropped. A priority based on CSI mode/type determines which CSI shall be reported. 
         [0004]    For CSI may include Channel Quality Indicator/Precoding Matrix Indicator/Rank Indicator (CQI/PMI/RI). In CQI/PMI/RI feedback in down link (DL) carrier aggregation (CA), the reporting parameters periodicity and offset can be independently configured for each CC. Then collision of CSI reports form different CCs can be usually avoided by reasonable eNB implementation. For cases where collision does happen such as eNB mis-configuration, the following handling procedures were proposed: 
         [0005]    Uplink control information (UCI) transmission on Physical Uplink Control CHannel (PUCCH) and Physical Uplink Shared CHannel (PUSCH) for carrier aggregation (CA) was discussed at the 3GPP RAN1 working group. For periodic UCI (PMI/CQI/RI) transmitted on PUCCH it was agreed that: 
         [0006]    (1) For periodic CQI/PMI/RI reporting for CA, at least configuration of different (in time) PUCCH resources for reports for each CC is supported. 
         [0007]    (2) If simultaneous PUCCH and PUSCH is configured and there is at least one PUSCH transmission on a serving cell then: if there is a collision between CSI and Hybrid Automatic Repeat Request Acknowledge (HARQ-ACK) in the same subframe, the HARQ-ACK is transmitted on PUCCH white the periodic CSI is transmitted on PUSCH; all UCI mapped onto PUSCH in a given subframe are mapped onto a single serving irrespective of the number of serving cells transmitting PUSCH on this subframe. 
         [0008]    The current standard agreement supports independent configuration of the RI/PMI/CQI reporting parameters per DL CC including subframe offset, periodicity and reporting mode. The eNB is left to configure the UCI periodicity/offset such that RI/PMI/CQI reports of different CCs does not collide in the time domain. This is possible because carrier aggregation is mostly applicable for low-mobility user equipment (UE) with good channel condition. Thus the channel variation is slow and a large RI/CQI/PMI periodicity suffices. In the event of a collision of CSI reports of two CCs there are two basic options. The first option supports a larger CSI payload format. The second option prioritizes a CSI type and/or CC by combining/dropping reports from different CCs and/or CSI types based on a pre-defined priority order. 
         [0009]    The PUCCH is an extremely narrow pipeline with limited in feedback capacity, CSI accuracy and granularity. It is beneficial not to increase the CSI reporting scenarios in order to minimize testing complexity. The impact of the dual-codebook structure on PUCCH CSI feedback should be considered. The following discusses the CSI feedback when a UE is configured for DL CA considering the PUCCH limitations. 
         [0010]    The dual-stage codebook structure has been adopted for the eight antenna ports(8 Tx) case. Each precoding matrix is the multiplication of two component matrices, given by W=W 1 ×W 2 , where W 1  is a wideband precoding matrix that is constant across the system bandwidth, and W 2  is a narrow-band precoding matrix that may vary on different frequency band. Two CSI modes are defined in Long Term Evolution (LTE) Rel. 10 for 8 Tx feedback on PUCCH. In submode 1 first precoding matrix/second precoding matrix (W 2 /W 2 ) are reported in different subframes. In submode 2 W1/W2 are reported in the same subframe. It is preferable to have the same CSI modes configured on different DL CCs. This simplifies the timing relationship between RI/CQI/PMI first precoding matrix (W 1 ) and second precoding matrix (W 2 ) report. 
         [0011]    The currently adopted standard does not concatenate Rank Indicator (RI) bits across different CCs into one PUCCH. RI bits of each CC are multiplexed in different subframes by configuring different PUCCH offsets and/or periodicities. This ensures the reliability of RI/W 2  feedback for ≧3 bits which significantly impacts the subsequent PMI/CQI report. The maximum RI payload per PUCCH should be equivalent to one DL CC. The exact payload of RI per CC should depend on the outcome of the PUCCH CSI mode discussion. 
         [0012]    For RI and CQI/PMI, the RI of a first CC and the PMI/CQI of a second CC should not be reported together in the same PUCCH so as to jeopardize the reliability of RI report. Likewise the eNB implementation should configure the feedback offsets and periodicities (N OFFSET,RI,  and N OFFSET,CQI ) of each CC intelligently. The following exemplary embodiments for UE procedure are given for when the RI of a first CC and CQI/PMI of a second CC occurs. 
         [0013]    When the RI of CC n and the PMI/CQI of CC m collides, CQI/PMI should be dropped or reported in PUSCH. When dropping is considered, use this order of priority: RI; wideband CQI/PMI; and subband CQI. Thus if RI of CC n collides with PMI/CQI of CC m, PMI/CQI is dropped. If wideband PMI/CQI of CC n collides with subband PMI of CC m, subband PMI is dropped. The CSI of the SCell may always be dropped when CSI of PCell collides with CSI of SCell. Alternatively all CSI can be piggy-backed in PUSCH in case collision occurs. This PUSCH transmission may be triggered with an explicit UL grant, or semi-statically configured by higher layer without an UL grant, such as triggered by the event of CSI collision between different CC. In this case PUSCH is preferably scheduled on PCC. 
         [0014]    For the LTE Rel. 8/9 standard if a collision occurs between CQI/PMI/RI and Hybrid Automatic Repeat Request-Acknowledge (HARQ-ACK) transmission, the CQI/PMI/RI is dropped. This may lead to frequent dropping of CSI reports in the LTE Rel. 10 standard because all HARQ-ACK feedback from all DL CCs is sent on the PUCCH of the UL PCC. Increasing the payload size or increasing the modulation to accommodate the CSI on PUSCH is not recommended because: this increases link budget requirements; and such new modulation or payload size does not scale for LTE Rel. 10 control signaling since support of up to 5 DL CCs is mandated for LTE Rel. 10. 
         [0015]    An alternative to avoid frequent dropping of CSI transmits periodic CSI on the PUSCH. When a UE is not configured for simultaneous PUCCH and PUSCH the CSI can only be transmitted when the UE is allocated an UL grant. Otherwise, the CSI is dropped. When the UE is configured for simultaneous PUCCH and PUSCH, one technique to avoid dropping of CSI is to transmit acknowledge/not acknowledge (ACK/NAK) on PUCCH and CSI on PUSCH. 
         [0016]    For periodic CQI/PMI/RI feedback in DL carrier aggregation, the reporting parameters of periodicity and offset can be independently configured for each CC. Thus collision of CSI reports of different CCs can be usually avoided by reasonable eNB implementation. When collisions do happen such as due to eNB mis-configuration), the following handling procedures were adopted. 
         [0017]    For periodic CQI/PMI/RI reporting, the set of higher-layer configuration parameters as defined in LTE Rel. 8 are independently configured for each DL component carrier. 
         [0018]    When simultaneous PUCCH and PUSCH is not configured, periodic CQI/PMI/RI is reported for only one DL component carrier (CC) in one subframe on PUCCH. The DL CC is determined according to a priority: prioritize between CCs based on CSI (CQI/PMI/RI) reporting mode/type; if the reporting mode/type is the same, prioritize by Radio Resource Control (RRC) configured priority between CCs; the same priority rule applies to both the case without PUSCH and the case with PUSCH. The CQI/PMI/RI for other DL component carriers is dropped. For the determined DL CC, the same LTE Rel. 8 procedure applies for collisions between RI, wideband CQI/PMI, subband CQI for the same CC. 
         [0019]    This application discusses the details of prioritization between different CSI reporting modes/types in case of collision between CQI/PMI/RI. 
         [0020]    Although dropping CQI/PMI/RI based on the CSI mode/type is feasible, this leads to a quite complicated UE behavior and non-trivial standardization work. The complicating issues are: different CCs may be configured in different transmission modes and hence different CSI modes; some CSI type is associated with a corresponding CSI mode but not another; some CC may have PMI enabled while other CC have PMI disabled; different CCs configured with different number of CSI-RS ports, such as four antenna ports (4 Tx) or 8 Tx, and hence different CSI mode/type; different CCs may have the same CSI modes but different Transmit Mode (TM), such as TM 3 (CRS-based feeback) vs. TM 9 (CSI-RS based feeback). 
         [0021]    The PUCCH report configuration is an implementation issue and collision can usually be avoided by appropriate PUCCH periodicity and offsets. Thus CQI/PMI/RI collision usually results from an erroneous network configuration case. Optimizing for this corner case is possible, but may result in little performance benefits not yet shown by system level simulation. Therefore a simpler solution that relies solely on a RRC configured priority of the CC itself is preferable. 
       SUMMARY OF THE INVENTION 
       [0022]    This application considers the need for enhancements to the baseline CSI reporting mechanisms including maximum payload size, CQI/PMI reporting configurations and CSI transmission in the event of collision between CSI reports from different CCs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    These and other aspects of this invention are illustrated in the drawings, in which: 
           [0024]      FIG. 1  illustrates an exemplary prior art wireless communication system to which this application is applicable; 
           [0025]      FIG. 2  shows the Evolved Universal Terrestrial Radio Access (E-UTRA) Time Division Duplex (TDD) frame structure of the prior art; 
           [0026]      FIG. 3  illustrates an exemplary block diagram in wireless communication system, where CSI feedback for two component carriers are compared such that CSI is reported for the component carrier with a higher CSI priority; 
           [0027]      FIG. 4  illustrates an exemplary CSI report selection method, wherein CSI selection is based on CSI type priority; 
           [0028]      FIG. 5  illustrates an exemplary CSI report selection method, wherein CSI selection is based first on CSI mode priority, followed by CSI type priority; 
           [0029]      FIG. 6  illustrates an exemplary CSI report selection method, wherein CSI selection is based on CSI group priority; and 
           [0030]      FIG. 7  is a block diagram illustrating internal details of a base station and a mobile user equipment in the network system of  FIG. 1  suitable for implementing this invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0031]      FIG. 1  shows an exemplary wireless telecommunications network  100 . The illustrative telecommunications network includes base stations  101 ,  102  and  103 , though in operation, a telecommunications network necessarily includes many more base stations. Each of base stations  101 ,  102  and  103  (eNB) are operable over corresponding coverage areas  104 ,  105  and  106 . Each base station&#39;s coverage area is further divided into cells. In the illustrated network, each base station&#39;s coverage area is divided into three cells. Handset or other user equipment (UE)  109  is shown in Cell A  108 . Cell A  108  is within coverage area  104  of base station  101 . Base station  101  transmits to and receives transmissions from UE  109 . As UE  109  moves out of Cell A  108  and into Cell B  107 , UE  109  may be handed over to base station  102 . Because UE  109  is synchronized with base station  101 , UE  109  can employ non-synchronized random access to initiate handover to base station  102 . 
         [0032]    Non-synchronized UE  109  also employs non-synchronous random access to request allocation of up-link  111  time or frequency or code resources. If UE  109  has data ready for transmission, which may be traffic data, measurements report, tracking area update, UE  109  can transmit a random access signal on up-link  111 . The random access signal notifies base station  101  that UE  109  requires up-link resources to transmit the UEs data. Base station  101  responds by transmitting to UE  109  via down-link  110 , a message containing the parameters of the resources allocated for UE  109  up-link transmission along with a possible timing error correction. After receiving the resource allocation and a possible timing advance message transmitted on down-link  110  by base station  101 , UE  109  optionally adjusts its transmit timing and transmits the data on up-link  111  employing the allotted resources during the prescribed time interval. 
         [0033]    Base station  101  configures UE  109  for periodic uplink sounding reference signal (SRS) transmission. Base station  101  estimates uplink channel state information (CSI) from the SRS transmission. 
         [0034]      FIG. 2  shows the Evolved Universal Terrestrial Radio Access (E-UTRA) time division duplex (TDD) Frame Structure. Different subframes are allocated for downlink (DL) or uplink (UL) transmissions. Table 1 shows applicable DL/UL subframe allocations. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Config- 
                 Switch-point 
                 Sub-frame number 
               
             
          
           
               
                 uration 
                 periodicity 
                 0 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
               
                 0 
                  5 ms 
                 D 
                 S 
                 U 
                 U 
                 U 
                 D 
                 S 
                 U 
                 U 
                 U 
               
               
                 1 
                  5 ms 
                 D 
                 S 
                 U 
                 U 
                 D 
                 D 
                 S 
                 U 
                 U 
                 D 
               
               
                 2 
                  5 ms 
                 D 
                 S 
                 U 
                 D 
                 D 
                 D 
                 S 
                 U 
                 D 
                 D 
               
               
                 3 
                 10 ms 
                 D 
                 S 
                 U 
                 U 
                 U 
                 D 
                 D 
                 D 
                 D 
                 D 
               
               
                 4 
                 10 ms 
                 D 
                 S 
                 U 
                 U 
                 D 
                 D 
                 D 
                 D 
                 D 
                 D 
               
               
                 5 
                 10 ms 
                 D 
                 S 
                 U 
                 D 
                 D 
                 D 
                 D 
                 D 
                 D 
                 D 
               
               
                 6 
                 10 ms 
                 D 
                 S 
                 U 
                 U 
                 U 
                 D 
                 S 
                 U 
                 U 
                 D 
               
               
                   
               
             
          
         
       
     
         [0035]    This invention includes preference on issues related to periodic CQI/PMI/RI transmission on PUCCH. The preferences are as follows. The system may configure a different PUCCH reporting mode (e.g. mode 1-0/1-1, 2-0/2-1) on each CC. There is no concatenation of RI of different CC on PUCCH in the same subframe. There is no concatenation of RI of a first CC and CQI/PMI of second CC on PUCCH in the same subframe. The maximum RI and CQI/PMI payload per CC depends on the outcome of PUCCH CSI mode selection. Re-use of LTE Rel. 8 Reed-Muller (RM) code occurs if the RI and PMI/CQI payload does not exceed 11-bits. 
         [0036]    Periodic CQI/PMI/RI is reported for only one DL component carrier (CC) in one subframe on PUCCH. The selected DL CC is determined according to the priority of the downlink carriers. The PCell should have higher priority than a SCell. 
         [0037]    Table 2 summarizes the PUCCH reporting mode/types in LTE Rel. 10 if a prioritization based on CSI mode/type is indeed necessary. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 CSI Mode 
                 TM mode 
                 Reporting contents 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 2 TX 
                 1-1 
                   
                 RI (3) 
                 WB CQI/PMI (2) 
                   
                   
               
               
                 4 Tx 
                 2-1 
                   
                 RI (3) 
                 WB CQI/PMI (2) 
                 SB CQI (1) 
               
               
                   
                 1-0 
                 TM 4/8/9 
                   
                 WB CQI (4) 
               
               
                   
                   
                 TM 3 
                 RI (3) 
                 WB CQI (4) 
               
               
                   
                 2-0 
                 TM 4/8/9 
                   
                 WB CQI (4) 
                 SB CQI (1) 
               
               
                   
                   
                 TM 3 
                 RI (3) 
                 WB CQI (4) 
                 SB CQI (1) 
               
               
                 8 Tx 
                 1-1, sub-mode 1 
                   
                 RI/W1(5) 
                 WB W2/CQI (2b) 
               
               
                   
                 1-1, sub-mode 2 
                   
                 RI (3) 
                 WB W1/W2/CQI 
               
               
                   
                   
                   
                   
                 (2c) 
               
               
                   
                 2-1 
                   
                 RI/PTI (6) 
                 WB W1 (2a) 
                 WB W2/CQI (2b) 
                 SB W2/CQI (1a) 
               
               
                   
                 1-0 
                   
                   
                 WB CQI (4) 
               
               
                   
                 2-0 
                   
                   
                 WB CQI (4) 
                 SB CQI (1) 
               
               
                   
               
             
          
         
       
     
         [0038]    There are two reports that have the same CSI mode but different CSI type. The same prioritization principles in LTE Rel. 8 can be re-used especially for 2/4 Tx antenna configuration. For 8 Tx a similar principle is applied for PUCCH mode 1-1, both sub mode 1 (W1 jointly encoded with RI) and sub mode 2 (W1 jointly encoded with W2/CQI). 
         [0039]    If different CC are configured with the same CSI mode, then for 2/4 Tx, RI (3) has a higher priority than wideband PMI/CQI (2), which has a higher priority than wideband CQI (4), which has a higher priority than sub band CQI (1). For 8 Tx and PUCCH mode 1-1 sub mode 1, then RI/W1(5) has a higher priority than W2/CQI (2b). For 8 Tx and PUCCH mode 1-1, sub mode 2, then RI (3) has a higher priority than W1/W2/CQI (2c). 
         [0040]    For 8 Tx PUCCH mode 2-1, the introduction of Precoding Type Indicator (PTI) bit requires additional prioritization rule. The PUCCH 2-1 feedback structure is as follows. Report 1 is RI and 1-bit precoding type indication (PTI). Report 2, when PTI=0 wideband W1 will be reported and when PTI=1 wideband CQI and wideband W2 will be reported. Report 3, when PTI=0 wideband CQI and wideband W2 will be reported and when PTI=1 subband CQI and subband W2 will be reported. 
         [0041]    RI/PTI should be given the highest priority as it determines the reporting structure of W1/W2/CQI. Wideband W1 alone (following PTI=0) should be given the second highest priority, because W1 has a lower effective reporting periodicity than W2/CQI and should be protected to avoid PUCCH ambiguity in case of a lost W1 report. 
         [0042]    For 8 Tx PUCCH mode 2-1, priority is given as RI/PTI (6) has a higher priority than wideband W1 (2a) which has a higher priority than wideband CQI/W2 (2b) which has a higher priority than subband CQI/W2 (1a). 
         [0043]    In case two CSI reports are associated with different CSI modes, there are two possible cases. The first case has different CSI modes and the same CSI type. The second case has different CSI mode and different CSI types. It is possible to tabulate the priority order for all mode and type combination. Since there is a large number of possible combinations stemming from 7 modes and 10 types, this is unnecessarily complicated. In addition, no performance gain has been shown requiring such a practice. 
         [0044]    A simpler alternative determines the priority order based on the reporting modes and drops the lower priority. If the reporting modes are identical, this simplifies alternative drops the CQI/PMI/RI based on the CSI type. 
         [0045]    This alternative prioritizes the PUCCH report on the following principles. First, this alternative decides based on CSI mode priority. The CQI/PMI/RI of a lower priority reporting mode is dropped. Second, this alternative decides based on CSI type priority. The CQI/PMI/RI of a lower priority reporting type is dropped. 
         [0046]    Prioritization may depend on whether PMI feedback is included. With independent PMI configuration per CC either due to different transmission mode or due to PMI enabling/disabling, one CC may have the PMI report enabled while another CC has its PMI feedback disabled. RI/PMI feedback constitutes an important feedback component for downlink beamforming and should be preserved whenever possible. Because CQI is derived based on PMI once PMI is dropped due to collision, then the ensuing CSI report loses its reference and becomes less useful. 
         [0047]    In another embodiment of this invention the CQI/PMI/RI report for a CC with PMI enabled is prioritized over CQI/PMI/RI report for another CC with PMI disabled. Therefore PUCCH mode 1-1/2-1 is prioritized over mode 1-0/2-0. PUCCH mode 1-0 is prioritized over mode 2-0. PUCCH mode 1-1 is prioritized over mode 2-1. 
         [0048]    For 8 Tx PUCCH mode 1-1, sub mode 1 (W1 jointly encoded with RI) and sub mode 2 (W1 jointly encoded with W2/CQI) are possible. Due to the 8 Tx codebook size (max 4-bit W1, max 4-bit W2, max 7-bit CQI), joint encoding of W1 and W2/CQI incurs significant codebook sub-sampling to accommodate the 11-bit PUCCH payload. This reduces the CQI feedback accuracy and DL throughput. To avoid heavy codebook sub-sampling, it is preferable to prioritize sub mode 1 to maintain higher feedback accuracy. 
         [0049]    For 8 Tx, PUCCH mode 1-1 sub mode 1 is prioritized over sub mode 2. If RI/W1 (sub-mode 1) collides with RI (sub-mode 2), RI is dropped. If W2/CQI (sub-mode 1) collides with PMI/CQI (sub-mode 2), PMI/CQI is dropped. 
         [0050]    Even if the CSI mode and type are completely identical, a number of issues may also affect the reporting priority. The UE configured in transmission mode 9 (TM9) in LTE Rel. 10 performs channel measurement based on CSI-RS. A UE-specific CSI-RS configuration has been proposed for the standard. If UE-specific CSI-RS is adopted, the standard should further clarify whether or not the UE-specific CSI-RS configuration shall be CC-common or CC-specific. Note UE-specific L1 parameters, such as transmission mode, CQI/PMI/RI reporting configuration, are usually assumed configurable on a CC-specific basis. 
         [0051]    Whether or not CSI-RS can be configured CC-specific basis needs to be clarified if UE-specific CSI-RS configuration is adopted. 
         [0052]    If number of CSI-RS antenna ports configuration is CC-specific, a higher priority is preferable for a CC with a larger number of CSI-RS antenna ports. This generally requires more spatial resolution and feedback accuracy. 
         [0053]    The CQI/PMI/RI report for 1 2/4/8 CSI-RS antenna ports shall be allocated with an increasing priority order. 
         [0054]    One possibility is to prioritize the CSI report entirely on CSI type, and independent of the CSI mode. The 7 CSI reporting type can be categorized into three groups, where different groups have different priority. CSI in a lower-priority group is dropped if collided with another CSI report in a higher priority group. 
         [0055]    This invention proposes the following CSI grouping: Group 1 is RI (and its variant), including RI (Type 3), RI/W1 (Type 5), RI/PTI (Type 6); Group 2 is wideband CQI/PMI (and its variant), including Wideband CQI/PMI (Type 2), CQI (Type 4), W1 (Type 2a), W2/CQI (Type 2b), W1/W2/CQI (2c); and Group 3 is subband CQI/PMI, including Subband CQI (Type 1), subband W2/CQI (Type 1a). The inter-group prioritization is group 1 has a higher priority than group 2 which has a higher priority than group 3. If two colliding CSI reports belong to the same group, further prioritization is performed and a lower priority report is dropped. 
         [0056]    In another embodiment, Group 1 includes RI (Type 3), RI/W1 (Type 5), RI/PTI (Type 6), and wideband W1 (Type 2a); Group 2 is wideband CQI/PMI (and its variant), including Wideband CQI/PMI (Type 2), CQI (Type 4), W2/CQI (Type 2b), W1/W2/CQI (Type 2c); and Group 3 is subband CQI/PMI, including Subband CQI (Type 1), subband W2/CQI (Type 1a). The inter-group prioritization is group 1 has a higher priority than group 2 which has a higher priority than group 3. If two colliding CSI reports belong to the same group, further prioritization is performed and a lower priority report is dropped. 
         [0057]    This invention proposed the following intra-group prioritization. For Group 1: in a first alternative RI/W1 (5) has a higher priority than RI (3) which has a higher priority than RI/PTI (6); in a second alternative RI (3) has a higher priority than RI/W1 (5) which has a higher priority than RI/PTI (6). For Group 2: in a first alternative W2/CQI (2b) has a higher priority than W1/W2/CQI (2c) which has a higher priority than W1(2a) which has a higher priority than CQI/PMI (2) which has a higher priority than CQI (4); in a second alternative W1/W2/CQI (2c) has a priority higher than W2/CQI (2b) which has a higher priority than W1(2a) which has a higher priority than CQI/PMI (2) which has a higher priority than CQI (4). For Group 3, subband W2/CQI (1a) has a higher priority than subband CQI (1). 
         [0058]    In another embodiment, if two colliding CSI reports belong to the same priority group, CSI of the DL component carrier with a larger component carrier index is dropped. 
         [0059]    In another embodiment, if two CSI reports are of the same type but are associated with different reporting modes, further prioritization based on CSI mode can be considered, for example based on rules above. 
         [0060]    This application concerns the CSI mode/type prioritization order for PUCCH report in DL CC. The following principles are proposed. 
         [0061]    The CQI/PMI/RI report for 1 2/4/8 CSI-RS antenna ports shall be allocated with an increasing priority order. If the CSI modes are not identical, then for 2/4 Tx: PUCCH mode 1-1/2-1 is prioritized over mode 1-0/2-0; PUCCH mode 1-0 is prioritized over mode 2-0; and PUCCH mode 1-1 is prioritized over mode 2-1. For 8 Tx PUCCH mode 1-1 sub-mode 1 is prioritized over sub-mode 2. If the CSI mode are identical then for 2/4 Tx: RI (3) is prioritized over wideband PMI/CQI (2) is prioritized over wideband CQI (4) is prioritized over sub band CQI (1). For 8 Tx; for PUCCH mode 1-1, sub-mode 1 RI/W1(5) is prioritized over W2/CQI (2b); for PUCCH mode 1-1, sub-mode 2 RI (3) is prioritized over W1/W2/CQI (2c); and for PUCCH mode 2-1 RI/PTI (6) is prioritized over wideband W1 (2a) is prioritized over wideband CQI/W2 (2b) is prioritized over subband CQI/W2 (1a). 
         [0062]      FIG. 3  is an operations flow diagram illustrating a wireless communication system where CSI feedback for two component carriers are compared an CSI is reported for the component carrier with a higher CSI priority.  FIG. 3  illustrates user equipment (UE)  310  and base station (eNB)  320 . Within eNB  320  DL Reference Signal Generator  321  generates a reference signal which is supplied to UE  310  via downlink  301 . 
         [0063]    Within UE  310  the reference signal supplies CSI measurement for CC1 block  311  and CSI measurement for CC2 block  313 . CSI measurement for CC1 block  311  measures the reference signal as applied to CC1 and supplies CSI report for CC1 block  312 . Likewise measurement for CC2 block  313  measures the reference signal as applied to CC2 and supplies CSI report for CC2 block  314 . Both CSI report blocks  312  and  314  supply reports to CSI priority determination block  315 . CSI priority determination block  315  supplies the determined priorities to block  316 . Block  316  selects one of the DL CC having the highest priority. Block  316  supplies this selected DL CC to CSI encoding block  317 . CSI encoding block  317  encodes the selected response to the DL reference signal on PUCCH. This radio frequency signal is supplied to eNB  320  via uplink  302 . 
         [0064]    CSI decoding/demodulation block  322  of eNB  320  decodes and demodulates the signal from uplink  302 . The decoded and demodulate signal is supplied to block  323 . Block  323  provides various functions such as: scheduling link adaptation; multiple input, multiple output (MIMO) precoding; and data transmission. Block  323  includes block  324  for DL data processing. 
         [0065]      FIG. 4  is a flow chart  400  of an exemplary CSI report selection method where CSI selection is based on CSI type priority. Flow chart  400  receives inputs for CSI CC1 at block  401  and CSI CC2 at block  402 . 
         [0066]    Test block  403  receives both input and determines if the CSI type priority of CC1 equals the CSI type priority of CC2. If this is true (Yes at test block  403 ), then block  404  determines the relative priority of CC1 and CC2 by other rules. Following priority determination in block  404 , block  405  encodes and modulates the selected CC on PUCCH. 
         [0067]    If the CSI type priority of CC1 does not equal that of CC2 (No at test block  403 ), then test block  406  determines if the CSI type priority of CC1 is greater than the CSI priority of CC2. If this is true (Yes at text block  406 ), then block  407  selects CC1 for CSI and drops CC2. Block  405  encodes and modulates CC1 on PUCCH. If this is not true (No at text block  406 ), then block  408  selects CC2 for CSI and drops CC1. Block  405  encodes and modulates CC2 on PUCCH. 
         [0068]      FIG. 5  is a flow chart  500  of an exemplary CSI report selection method where CSI selection is based first on CSI mode priority followed by CSI type priority. Flow chart  500  receives inputs for CSI CC1 at block  501  and CSI CC2 at block  502 . 
         [0069]    Test block  503  receives both input and determines if the CSI mode priority of CC1 equals the CSI mode priority of CC2. If this is true (Yes at test block  503 ), then test block  504  determines if the CSI type priority of CC1 is greater than that of CC2. If this is true (Yes at test block  504 ) then block  505  selects CC1 for CSI and drops CC2. Following priority determination in block  505 , block  506  encodes and modulates CC1 on PUCCH. 
         [0070]    If the CSI type priority of CC1 is not greater than that of CC2 (No at test block  504 ) then block  507  selects CC2 for CSI and drops CC1. Following priority determination in block  507 , block  506  encodes and modulates CC2 on PUCCH. 
         [0071]    If the CSI mode priority of CC1 does not equal that of CC2 (No at test block  503 ), then test block  508  determines if the CSI mode priority of CC1 is greater than the CSI mode priority of CC2. If this is true (Yes at text block  508 ), then block  509  selects CC1 for CSI and drops CC2. Block  506  encodes and modulates CC1 on PUCCH. If this is not true (No at test block  508 ), then block  510  selects CC2 for CSI and drops CC1. Block  506  encodes and modulates CC2 on PUCCH. 
         [0072]      FIG. 6  is a flow chart  600  of an exemplary CSI report selection method where CSI selection is based on CSI group priority. Flow chart  600  receives inputs for CSI CC1 at block  601  and CSI CC2 at block  602 . Block  603  determines the CSI priority group 
         [0073]    Test block  604  receives the determined CSI group for the two inputs and determines if the CSI group priority of CC1 equals the CSI group priority of CC2. If this is true (Yes at test block  604 ), then block  605  determines the relative priority of CC1 and CC2 by other rules. Following priority determination in block  605 , block  606  encodes and modulates the selected CC on PUCCH. 
         [0074]    If the CSI group priority of CC1 does not equal that of CC2 (No at test block  604 ), then test block  607  determines if the CSI group priority of CC1 is greater than the CSI group priority of CC2. If this is true (Yes at text block ( 608 ), then block  608  selects CC1 for CSI and drops CC2. Block  606  encodes and modulates CC1 on PUCCH. If this is not true (No at text block  607 ), then block  609  selects CC2 for CSI and drops CC1. Block  606  encodes and modulates CC2 on PUCCH. 
         [0075]      FIG. 7  is a block diagram illustrating internal details of an eNB  1002  and a mobile UE  1001  in the network system of  FIG. 1 . Mobile UE  1001  may represent any of a variety of devices such as a server, a desktop computer, a laptop computer, a cellular phone, a Personal Digital Assistant (PDA), a smart phone or other electronic devices. In some embodiments, the electronic mobile UE  1001  communicates with eNB  1002  based on a LTE or Evolved Universal Terrestrial Radio Access Network (E-UTRAN) protocol. Alternatively, another communication protocol now known or later developed can be used. 
         [0076]    Mobile UE  1001  comprises a processor  1010  coupled to a memory  1012  and a transceiver  1020 . The memory  1012  stores (software) applications  1014  for execution by the processor  1010 . The applications could comprise any known or future application useful for individuals or organizations. These applications could be categorized as operating systems (OS), device drivers, databases, multimedia tools, presentation tools, Internet browsers, emailers, Voice-Over-Internet Protocol (VOIP) tools, file browsers, firewalls, instant messaging, finance tools, games, word processors or other categories. Regardless of the exact nature of the applications, at least some of the applications may direct the mobile UE  1001  to transmit UL signals to eNB (base-station)  1002  periodically or continuously via the transceiver  1020 . In at least some embodiments, the mobile UE  1001  identifies a Quality of Service (QoS) requirement when requesting an uplink resource from eNB  1002 . In some cases, the QoS requirement may be implicitly derived by eNB  1002  from the type of traffic supported by the mobile UE  1001 . As an example, VOIP and gaming applications often involve low-latency uplink (UL) transmissions while High Throughput (HTP)/Hypertext Transmission Protocol (HTTP) traffic can involve high-latency uplink transmissions. 
         [0077]    Transceiver  1020  includes uplink logic which may be implemented by execution of instructions that control the operation of the transceiver. Some of these instructions may be stored in memory  1012  and executed when needed by processor  1010 . As would be understood by one of skill in the art, the components of the uplink logic may involve the physical (PHY) layer and/or the Media Access Control (MAC) layer of the transceiver  1020 . Transceiver  1020  includes one or more receivers  1022  and one or more transmitters  1024 . 
         [0078]    Processor  1010  may send or receive data to various input/output devices  1026 . A subscriber identity module (SIM) card stores and retrieves information used for making calls via the cellular system. A Bluetooth baseband unit may be provided for wireless connection to a microphone and headset for sending and receiving voice data. Processor  1010  may send information to a display unit for interaction with a user of mobile UE  1001  during a call process. The display may also display pictures received from the network, from a local camera, or from other sources such as a Universal Serial Bus (USB) connector. Processor  1010  may also send a video stream to the display that is received from various sources such as the cellular network via RF transceiver  1020  or the camera. 
         [0079]    During transmission and reception of voice data or other application data, transmitter  1024  may be or become non-synchronized with its serving eNB. In this case, it sends a random access signal. As part of this procedure, it determines a preferred size for the next data transmission, referred to as a message, by using a power threshold value provided by the serving eNB, as described in more detail above. In this embodiment, the message preferred size determination is embodied by executing instructions stored in memory  1012  by processor  1010 . In other embodiments, the message size determination may be embodied by a separate processor/memory unit, by a hardwired state machine, or by other types of control logic, for example. 
         [0080]    eNB  1002  comprises a Processor  1030  coupled to a memory  1032 , symbol processing circuitry  1038 , and a transceiver  1040  via backplane bus  1036 . The memory stores applications  1034  for execution by processor  1030 . The applications could comprise any known or future application useful for managing wireless communications. At least some of the applications  1034  may direct eNB  1002  to manage transmissions to or from mobile UE  1001 . 
         [0081]    Transceiver  1040  comprises an uplink Resource Manager, which enables eNB  1002  to selectively allocate uplink Physical Uplink Shared CHannel (PUSCH) resources to mobile UE  1001 . As would be understood by one of skill in the art, the components of the uplink resource manager may involve the physical (PHY) layer and/or the Media Access Control (MAC) layer of the transceiver  1040 . Transceiver  1040  includes at least one receiver  1042  for receiving transmissions from various UEs within range of eNB  1002  and at least one transmitter  1044  for transmitting data and control information to the various UEs within range of eNB  1002 . 
         [0082]    The uplink resource manager executes instructions that control the operation of transceiver  1040 . Some of these instructions may be located in memory  1032  and executed when needed on processor  1030 . The resource manager controls the transmission resources allocated to each UE  1001  served by eNB  1002  and broadcasts control information via the PDCCH. 
         [0083]    Symbol processing circuitry  1038  performs demodulation using known techniques. Random access signals are demodulated in symbol processing circuitry  1038 . 
         [0084]    During transmission and reception of voice data or other application data, receiver  1042  may receive a random access signal from a UE  1001 . The random access signal is encoded to request a message size that is preferred by UE  1001 . UE  1001  determines the preferred message size by using a message threshold provided by eNB  1002 . In this embodiment, the message threshold calculation is embodied by executing instructions stored in memory  1032  by processor  1030 . In other embodiments, the threshold calculation may be embodied by a separate processor/memory unit, by a hardwired state machine, or by other types of control logic, for example. Alternatively, in some networks the message threshold is a fixed value that may be stored in memory  1032 , for example. In response to receiving the message size request, eNB  1002  schedules an appropriate set of resources and notifies UE  1001  with a resource grant.