Abstract:
A method and apparatus for reducing modulation and coding scheme (MCS) signaling overhead includes receiving a channel quality indicator (CQI) feedback. It is determined if there is a CQI feedback error. An MCS indicator is transmitted based upon the CQI feedback error determination.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/915,135, filed May 1, 2007, which is incorporated by reference as if fully set forth. 
     
    
     FIELD OF INVENTION 
       [0002]    This application is related to wireless communications. 
       BACKGROUND 
       [0003]    In a wireless communication system, signaling overhead can result in transmission inefficiencies and non-optimal utilization of available bandwidth. An evolved Node-B (eNB) may utilize channel quality indicator (CQI) feedback received from a wireless transmit/receive unit (WTRU) in order to determine a modulation and coding scheme (MCS) to use for transmission. 
         [0004]    A WTRU typically reports CQIs to the eNB. The CQI is an index to an entry of a CQI table representing an MCS. The eNB receives reported CQIs from the WTRU and makes a decision about the corresponding proper modulation and coding scheme that should be used according to these reported CQIs. Once the MCS is selected, the eNB uses the corresponding MCS to perform adaptive modulation and coding (AMC) in downlink transmissions. In order for the WTRU to perform data detection correctly, the MCS used at the eNB should be known to the WTRU. One way to accomplish this is to send the full information about MCS to the WTRU via a physical downlink control channel (PDCCH). When the MCS table size is large, a large number of bits are required to represent an MCS. Furthermore, when multiple-in multiple-out (MIMO) is used, information for multiple MCSs for multiple spatial data streams or multiple codewords may be required to be signaled to the WTRU. 
         [0005]    It would be beneficial to provide a method and apparatus for reducing MCS signaling overhead. 
       SUMMARY 
       [0006]    A method and apparatus for reducing the signaling overhead for modulation and coding scheme (MCS) and/or transport block set or size (TBS) information is disclosed. The method includes receiving a channel quality indicator (CQI) feedback. It is determined whether or not there is a CQI feedback error (or whether or not a CQI feedback is reliable). An MCS indicator is transmitted based upon the CQI feedback error or reliability determination. MCS indicator may indicate the confirmation to the WTRU&#39;s feedback. MCS indicator may also indicate the MCS information or TBS information. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0007]    A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: 
           [0008]      FIG. 1  shows an example wireless communication system including a plurality of WTRUs and an eNB; 
           [0009]      FIG. 2  is an example functional block diagram of a WTRU and the eNB of  FIG. 1 ; 
           [0010]      FIG. 3  is a flow diagram of a method of reducing signaling overhead; 
           [0011]      FIG. 4  is an example frame format for reducing signaling overhead; 
           [0012]      FIG. 5  is an alternative example frame format for reducing signaling overhead; and 
           [0013]      FIG. 6  is a flow diagram of a method for indicating MCS/TBS information. 
       
    
    
     DETAILED DESCRIPTION  
       [0014]    When referred to hereafter, the terminology “wireless transmit/receive unit (WTRU)” includes but is not limited to a user equipment (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 “base station” includes but is not limited to a Node-B, a site controller, an access point (AP), or any other type of interfacing device capable of operating in a wireless environment. 
         [0015]      FIG. 1  shows an example wireless communication system  100  including a plurality of WTRUs  110  and an eNB  120 . As shown in  FIG. 1 , the WTRUs  110  are in communication with the eNB  120 . It should be noted that, although an example configuration of WTRUs  110  and eNB  120  is depicted in  FIG. 1 , any combination of wireless and wired devices may be included in the wireless communication system  100 . 
         [0016]      FIG. 2  is an example functional block diagram  200  of a WTRU  110  and the eNB  120  of the wireless communication system  100  of  FIG. 1 . As shown in  FIG. 2 , the WTRU  110  is in communication with the eNB  120 . The eNB  120  is configured to receive CQI feedback information from the WTRU  110  and signal an MCS to the WTRU. 
         [0017]    In addition to the components that may be found in a typical WTRU, the WTRU  110  includes a processor  115 , a receiver  116 , a transmitter  117 , and an antenna  118 . The receiver  116  and the transmitter  117  are in communication with the processor  115 . The antenna  118  is in communication with both the receiver  116  and the transmitter  117  to facilitate the transmission and reception of wireless data. The processor  115  of the WTRU  110  is configured to transmit CQI feedback to the eNB  120 , such as via transmitter  117 , and is configured to receive an MCS from the eNB  120 , such as via the receiver  116 . 
         [0018]    In addition to the components that may be found in a typical eNB, the eNB  120  includes a processor  125 , a receiver  126 , a transmitter  127 , and an antenna  128 . The receiver  126  and the transmitter  127  are in communication with the processor  125 . The antenna  128  is in communication with both the receiver  126  and the transmitter  127  to facilitate the transmission and reception of wireless data. The processor  125  of the eNB  120  is configured to receive a CQI feedback from a WTRU  110 , such as via the receiver  126 , and is configured to transmit an MCS indicator to the WTRUs  110 , such as via the transmitter  127 . 
         [0019]      FIG. 3  is a method of reducing signaling overhead  300 . In step  310 , a WTRU  110  sends a CQI feedback to the eNB  120 , which may be a single CQI feedback or multiple CQI feedbacks. The eNB  120  receives the CQI feedback and determines whether or not the CQI feedback is correct and reliable. Nominally, the CQI block error rate is about one to ten percent (1-10%), meaning that approximately ninety to ninety-nine percent (90-99%) of the time, the CQIs are received correctly. If there is no CQI feedback error (step  320 ), and if the eNB does not desire to override the WTRU  110  CQI feedback (step  350 ), then the WTRU  110  and the eNB  120  utilize the same MCS that corresponds to the most recently reported CQI that was fed back from the WTRU  110  (step  360 ). The eNB  120  transmits an MCS indicator to the WTRU  110  indicating to the WTRU  110  that the eNB  120  is utilizing the same CQI feedback. 
         [0020]    A one (1)-bit indicator may be embedded in a downlink (DL) scheduling grant, (e.g., within PDCCH), or transmitted independently to the WTRU  110 , that will alert the WTRU  110  that the same MCS and/or transport block size (TBS) that corresponds to the most recently reported CQI that was fed back from the WTRU  110  is to be used. No actual MCS and/or TBS information is required to be sent from the eNB  120  to the WTRU  110 . The MCS indicator may be a single indicator utilized for multiple codewords, or multiple MCS indicators may be utilized, such as one for each codeword. 
         [0021]    If a CQI feedback error was detected in step  320 , the CQI feedback was unreliable, or the eNB  120  desires to override the WTRU CQI feedback in step  350 , then the eNB  120  sends an MCS indicator to the WTRU  110  informing it of errors (step  330 ). Additionally, the eNB  120  may send the MCS and/or TBS information (step  340 ), (e.g., payload, modulation). If any two of the payload, modulation, and coding rate are known, then the third one may be derived. For example, in order to determine the TBS, the number of resource blocks (RBs) along with the modulation, coding rate or payload size should be known. The number of RBs that may be assigned to the WTRU  110  may be signaled to WTRU  110  via a control channel, (e.g., via PDCCH). Each RB may consist of M resource elements (REs). The MCS can indicate how many information bits are carried by, for example, W bits per RE. If there are N RBs assigned to the WTRU  110 , then the TBS will be approximately N×M×W bits. The payload size may indicate a TBS corresponding to an assigned number of RBs or a payload size per RB. 
         [0022]    Alternatively, the eNB  120  and the WTRU  110  may utilize a default MCS and/or TBS (step  345 ). The default MCS and/or TBS may be predefined and known to both the WTRU  110  and the eNB  120 . The default MCS and/or TBS may be used when there is a negative confirmation that may be due to an override or when there is a feedback error. Previously used MCS and/or TBS information may also be used if there is a feedback error provided the previously used MCS and/or TBS information is still valid. 
         [0023]      FIG. 4  is an example frame format  400  for reducing signaling overhead. The frame format  400  includes a UE ID field  410 , an MCS indicator (MCS_IND) field  420 , a resource assignment (Assign) field  430 , a codeword (CW)  1  payload field  440 , a CW 1  Modulation (Mod) field  450 , a CW 1  hybrid automatic repeat request (HARQ) info field  460 , and a multiple-in multiple-out (MIMO) info field  470 . The resource assignment field  430  may indicate a number of RBs assigned and their locations. The CW 1  modulation field  450  may indicate the modulation order for codeword  1 . The CW 1  HARQ info field  460  may include HARQ parameters such as incremental redundancy version (RV) and new data indicator (NDI). The MIMO info field  470  may include MIMO information such as rank, precoding, and the like. For purposes of example, the frame format  400  may be utilized in quadrature phase shift keying (QPSK), 1/3. Additionally, the CW 1  payload and CW 1  MOD fields can be combined into one single field to indicate a TBS that contains modulation and coding information for a given number of RBs. 
         [0024]    It should be noted that the fields depicted in the example frame format  400  are for example purposes. Some fields may not need to be present in the example frame format  400  and some fields may be combined. For example, the codeword (CW)  1  payload field  440  and CW 1  Modulation (Mod) field  450  may not be needed and may be eliminated from format  400 . Alternatively, the codeword (CW)  1  payload field  440  and CW 1  Modulation (Mod) field  450  may be combined together, or also into the MCS indicator field  420 . That is, the MCS indicator field  420  may include the codeword (CW)  1  payload field  440  and the CW 1  Modulation (Mod) field  450  in a single field with the same or different, (e.g., reduced) number of bits. 
         [0025]    The MCS indicator field  420  may include one value, such as “zero” (0) as an MCS confirmation, (i.e., a positive-confirmation message), to indicate that the MCS and/or TBS used at the eNB  120  and the WTRU  110  are identical and where there is no CQI feedback error and/or desire by the eNB  120  to override the WTRU  110  CQI feedback. The MCS indicator field may include a second value, such as a “one” (1) as a negative confirmation message to indicate that the MCS and/or TBS used at the eNB  120  and the WTRU  110  are not identical, such as when there is a CQI feedback error or there is a desire by the eNB  120  to override the WTRU  110  CQI feedback. For example, the eNB  120  may override the WTRU  110  CQI feedback for scheduling reasons or because of a network issue. 
         [0026]      FIG. 5  is an example frame format  500  for reducing signaling overhead. The frame format  500  includes a UE ID field  510 , an MCS_IND field  520 , a resource assignment (Assign) field  530 , a CW 1  payload field  540 , a CW 1  Mod field  550 , a CW 1  HARQ info field  460 , a CW 2  payload field  545 , a CW 2  Mod field  555 , a CW 2  HARQ info field  565 , and a MIMO info field  570 . 
         [0027]    It should be noted that the fields depicted in the example frame format  400  are for example purposes. Some fields may not need to be present in the example frame format  500  and some fields may be combined. The CW 1  payload field  540  and CW 1  Mod field  550  may be combined into a single filed to indicate a first codeword TBS that contains modulation and coding information for a given number of RBs. The CW 2  payload field  545  and CW 2  Mod field  555  may be combined into a single field to indicate a second codeword TBS that contains modulation and coding information for a given number of RBs. For purposes of example, the frame format  500  may be utilized in QPSK, 1/2. The fields of example frame format  500  are substantially similar in purpose to those of example frame format  400 . 
         [0028]    Accordingly, signal overhead may be reduced significantly. For example, assuming the CQI feedback block error rate is 1%, 1 bit is utilized for the eNB  120  to confirm the MCS to the WTRU  110  and 5 bits are utilized for the eNB  120  to transmit the MCS to the WTRU  110  for adaptive modulation and control (AMC). For a single codeword, and for every 100 downlink (DL) MCS information messages corresponding to the 100 uplink (UL) CQI feedbacks, using DL MCS indicator signaling, the signaling overhead for downlink is D=99×1+1×(1+5)=105 bits per 100 DL MCS information messages. In this case, the MCS indicator uses one bit for the WTRU&#39;s feedback to be confirmed. 
         [0029]    The signaling overhead for downlink without an MCS indicator is D=100×5=500 bits per 100 DL MCS information messages. Accordingly, the MCS signaling overhead is reduced by approximately 80% for a single codeword. More reductions occur for double or multiple codewords schemes that have two or more codewords. 
         [0030]    In the examples described previously, the MCS indicator may use 1 bit for MCS confirmation, where a “0” indicates positive confirmation message and “1” indicates a negative confirmation message. Additional bits may be used for the MCS indicator for indicating the MCS information message. That is, additional bits may be used for an indication of MCS and/or TBS information. For example, four bits, such as “0000”-“1111”, may indicate MCS and/or TBS information, for example, 16 kinds of MCS and /or TBS information for modulation and coding rates, (e.g., MCS# 1  to MCS# 16 ). In this case, an MCS indicator with both confirmation and information messages, one plus additional bits, may be used and transmitted. 
         [0031]    A corresponding example format for this scenario may be derived from the example frame format  400  of  FIG. 4 . That is that the CW 1  Payload field  440  and CW 1  MOD field  450  are combined into the MCS indicator field  420  in format  400  in  FIG. 4 . The MCS indicator field  420  contains the information of the CW 1  Payload field  440  and CW 1  MOD field  450 . Accordingly, the CW 1  Payload field  440  and CW 1  MOD field  450  may not be needed and may be removed in format  400 . 
         [0032]    If additional bits are not used for MCS and/or TBS information messages, (e.g., the WTRU  110  and/or eNB  120  is using default MCS and/or TBS information), then the MCS indicator may operate only as a confirmation message, either positive or negative. Only the MCS indicator with the confirmation message, (i.e., one bit), is transmitted. 
         [0033]    A corresponding example format for this scenario may also be derived from the example frame format  400  of  FIG. 4 . The CW 1  Payload field  440  and CW 1  MOD field may be eliminated from frame format  400  in  FIG. 4 . The MCS_IND field  420  then contains the confirmation message. 
         [0034]    If additional bits for MCS and/or TBS information messages are not used when a positive confirmation message is indicated, the MCS indicator with a confirmation message, (i.e., one bit), is transmitted if a positive confirmation is indicated and an MCS indicator with both confirmation and information messages, (i.e., one plus additional bits), is transmitted if a negative confirmation is indicated. 
         [0035]    A corresponding example format, (i.e., positive confirmation format), for the above scenario with relation to the example frame format  400  is that the CW 1  Payload field  440  and CW 1  MOD field  450  may be eliminated from frame format  400  in  FIG. 4 . The MCS indicator field  420  is used to indicate a confirmation message for MCS and/or TBS for the WTRU&#39;s feedback. Another corresponding example format, (i.e., negative confirmation format), for this scenario is that the CW 1  Payload field  440  and CW 1  MOD field  450  are not eliminated but combined into the MCS indicator field  420  in format  400  in  FIG. 4 . The MCS indicator field  420  contains the information of the CW 1  Payload field  440  and CW 1  MOD field  450 . Accordingly the CW 1  Payload field  440  and CW 1  MOD field may not be needed and may be removed in frame format  400 . The MCS indicator field  420  is then used to indicate confirmation and information messages for MCS and/or TBS. 
         [0036]    Although the example frame format  400  of  FIG. 4  was utilized in the examples described above, similar examples could be derived using the example frame format  500  of  FIG. 5 . 
         [0037]    Alternatively, the MCS indicator may use a bit sequence for combined encoding of MCS confirmation and information. 
         [0038]    The MCS indicator field  420  in  FIG. 4  or MCS indicator field  520  in  FIG. 5  may include one value, such as a “bit sequence 0” as an MCS confirmation to indicate that the MCS and/or TBS used at the eNB  120  and the WTRU  110  are identical and where there is no CQI feedback error and desire by the eNB  120  to override the WTRU  110  CQI feedback. The MCS indicator field may include other values, such as a “bit sequence x” as a combined negative confirmation message and information message to indicate that the MCS and/or TBS used at the eNB  120  and the WTRU  110  are not identical, such as when there is a CQI feedback error or there is a desire by the eNB  120  to override the WTRU  110  CQI feedback. This may also indicate the kind of MCS and/or TBS information that is used at the eNB  120  where x may indicate the kind of MCS and/or TBS information, (e.g., the index to a table containing MCS and/or TBS information). 
         [0039]    The MCS indicator field  520  in  FIG. 5  may include values to indicate one MCS and/or TBS confirmation message for multiple codewords, (i.e., one confirmation message for all codewords). The MCS indicator field  520  in  FIG. 5  may also include values to indicate multiple MCSs and/or TBSs confirmation messages for multiple codewords, (i.e., one confirmation message for each codeword). 
         [0040]    For example, the CW 1  PAYLOAD  540 , CW 1  MOD  550 , CW 2  PAYLOAD  545  and CW 2  MOD  555  fields can be removed from the example frame format  500  in  FIG. 5 . The MCS_IND field  520  may contain a single bit to indicate a confirmation message for all the codewords. The MCS_IND field  520  may also contain multiple bits, (e.g., two bits), to indicate a confirmation messages for all the codewords. For example, a first bit may indicate the confirmation message for the first codeword and a second bit may indicate the confirmation message for the second codeword and so on. 
         [0041]    The MCS indicator field  520  in  FIG. 5  may include values to indicate one MCS and/or TBS information message for multiple codewords, (i.e., one information message for all codewords). In addition, the MCS indicator field  520  in  FIG. 5  may also include values to indicate multiple MCSs and/or TBSs information messages for multiple codewords, (i.e., one information message for each codeword). 
         [0042]    For example, the MCS_IND field  520  may contain information in the CW 1  PAYLOAD  540 , CW 1  MOD  550 , CW 2  PAYLOAD  545  and CW 2  MOD  555  fields. Accordingly, the CW 1  PAYLOAD  540 , CW 1  MOD  550 , CW 2  PAYLOAD  545  and CW 2  MOD  555  fields may not be needed and can be removed from the example frame format  500  in  FIG. 5 . The MCS_IND field  520  may contain a bit sequence to indicate an information message for all the codewords. The MCS_IND field  520  may also contain bit sequences to indicate information messages for multiple codewords, (e.g., a first bit sequence indicates the information message for the first codeword and a second bit sequence indicates the information message for the second codeword and so on). A combined bit sequence, (e.g., by joint encoding) may also be used to indicate information messages for multiple codewords. 
         [0043]    Using 5 bits for the MCS indicator as an example, “00000” may indicate an MCS confirmation message that indicates the MCS and/or TBS information used at eNodeB is the same as those fed back from WTRU, and “00001” to “11111” may indicate MCS and/or TBS information messages, for example, 31 kinds of MCS and/or TBS information for modulation and coding rate, and the like, (e.g.,, MCS# 1  to MCS# 31 ). In this example, the MCS indicator is a combination of confirmation and information messages for MCS and/or TBS. That is, the MCS and/or TBS confirmation and indication messages are jointly encoded. 
         [0044]    For the same number of bits, such as 5 bits, joint encoding of confirmation and information messages for MCS and/or TBS may indicate more MCSs and/or TBS than separate encoding per MCS and/or TBS validation message, or 31 versus 16. On the other hand, separate encoding of MCS and/or TBS confirmation and information messages may allow more efficient signaling by sending only an MCS and/or TBS confirmation bit if the MCS and/or TBS information used at eNodeB is the same as those indicated by the CQI feedback from WTRU. For example, if there is no error, or if the CQI feedback signal is reliable and eNB  120  has no desire to override the WTRU  110 &#39;s CQI feedback, only a single bit for MCS and/or TBS confirmation is transmitted. 
         [0045]    Alternatively, different numbers of bits can be used for separate and joint encoding of MCS and/or TBS confirmation and information messages. To indicate the same number of MCSs and/or TBSs, separate encoding of confirmation and information messages may require one more bit for MCS and/or TBS confirmation purpose than joint encoding per an MCS signaling validation message. 
         [0046]    An MCS indicator can also signal additional types of messages, such as confirmation messages, information messages, override messages, and feedback error messages. A confirmation message is used to confirm that the MCS and/or TBS information used at the eNB  120  is the same as the MCS and/or TBS information, (e.g., indicated by CQI), fed back from WTRU  110 . An information message is used to indicate the MCS and/or TBS information, such as the kind of MCS and/or TBS that is used at the eNB  120 . An override message is used to indicate that the eNB  120  is overriding the WTRU&#39;s  110  CQI feedback and a new MCS and/or TBS information, such as an indicated MCS and/or TBS or a default MCS and/or TBS, is used at the eNB  120 . A feedback error message is used to indicate the WTRU&#39;s  110  CQI feedback is in error and the last used MCS and/or TBS information is used at the eNB  120 . 
         [0047]      FIG. 6  is a flow diagram of a method  600  for indicating MCS/TBS information. Either a different or the same MCS and/or TBS information may be used corresponding to different messages (step  610 ). 
         [0048]    If the same MCS and/or TBS is to be used, then the eNB  120  sends a confirmation message to the WTRU  110  (step  620 ). In this case, the same information regarding MCS and/or TBS indicated in CQI feedback from WTRU  110  may be used at the eNB  120  (step  630 ). 
         [0049]    Alternatively, if a different MCS and/or TBS is to be used, then the eNB  120  may send an information message (step  640 ), an override message (step  660 ), or a feedback error message ( 680 ). When sending and receiving an information message, it indicates that an MCS and/or TBS that is indicated and used by eNB  120  may be used by the WTRU  110  (step  650 ). When sending and receiving a override message, it indicates that a default MCS and/or TBS or another MCS and/or TBS that is indicated and used at the eNB  120  may be used at the WTRU  110  (step  670 ). When sending and receiving a feedback error message, it indicates that a last or previous used MCS and/or TBS at the eNB  120  and WTRU  110  may be used at the current time at the eNB  120  and WTRU  110  (step  690 ). Variants and combinations of these messages and the interpretation of these messages may also be utilized. More types of messages may also be included. 
         [0050]    An MCS table at the eNB  120 , or transmitter, could be a superset of a CQI/MCS table used at the WTRU  110 , or receiver. For example a 16QAM code rate 1/3 and QPSK code rate 2/3 may have the same spectral efficiency. Both a 16QAM code rate 1/3 and QPSK code rate 2/3 may be included in an MCS table at the eNB  120 , or transmitter. Additionally, if only the 16QAM code rate 1/3 is included in the CQI/MCS table at the WTRU  110 , or receiver, then when the CQI feedback from WTRU  110  indicates a 16QAM code rate 1/3, the eNB  120  may use either the MCS of the 16QAM code rate 1/3 or the MCS of QPSK code rate 2/3. 
         [0051]    Depending upon channel conditions one may be more desirable than the other. For example, in AWGN, a QPSK code rate 2/3 may perform better than a 16QAM code rate 1/3. This may reverse when the channel condition is that of a fading channel. While in a fading channel, a 16QAM code rate 1/3 may perform better than the QPSK code rate 2/3. The eNB  120  could measure the channel conditions, (e.g., AWGN, fading, and the like), and decide which modulation and coding rate should be used for optimum performance. 
         [0052]    If the eNB  120  in the above example uses the 16QAM code rate 1/3, a confirmation message is sent. However, if the eNB  120  uses the QPSK code rate 2/3, an override message is sent. 
         [0053]    Alternatively a confirmation message with an additional bit to indicate either 16QAM code rate 1/3 or QPSK code rate 2/3 may be used at the eNB  120 . 16QAM code rate 1/3 or QPSK code rate 2/3 may be treated as a pair. It may use an additional confirmation state, message or an additional information state or message instead of using an additional bit, to indicate the other MCS (QPSK code rate 2/3) of the pair when the feedback is 16QAM 1/3. Using a confirmation message, (e.g., using one bit or a bit sequence or bit combination), may reduce the number of bits to be sent for MCS and/or TBS signaling. 
         [0054]    If the eNB  120  uses an MCS other than 16QAM code rate 1/3 or QPSK code rate 2/3, an override message may be sent. If the eNB  120  detects the feedback is not reliable or has error, an error message is sent instead in accordance with step  330  of the method  300  or step  680  of the method  600 . 
         [0055]    When there are multiple CQIs each corresponding to a particular RB group (RBG) and the eNB  120  schedules downlink transmission on more than one RBG, then the eNB  120  may need to average, or further process, CQIs of these scheduled RBGs to select an appropriate MCS and/or TBS. Depending upon single or multiple codewords, one, two or more sets of MCSs and/or TBS information have to be produced and sent from the eNB  120  to the WTRU  110 . In this case, a formula or a mapping table can be used to produce the proper MCS information using CQI feedback. One equation that may be utilized is as follows: 
         [0000]      MCS information=f(CQI# 1 , CQI# 2 , . . . , CQI#M), 
         [0000]    where M is greater or equal to one, f( ) may be a function, formula or mapping table using the proper CQIs for MCS information mapping and generation. A simple f( ) may be a weighted or non-weighted averaging process or may come from a look-up table. An example of f( ) is log-normal average function. Such a function, formula or table should be known to both a transmitter, such as the eNB  120 , and a receiver, such as the WTRU  110 . It could be either hard coded/wired, stored in memory or signaled to ensure the interpretation for CQIs and MCSs and/or TBS are aligned and correct. 
         [0056]    The methods  300  and  600  described above may be applied to uplink communications, downlink communications, or both where applicable, and may be implemented in eNB to WTRU communication, WTRU to eNB communication, or bidirectionally. 
         [0057]    Although features and elements are described above in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements. The methods or flow charts provided herein may be implemented in a computer program, software, or firmware incorporated 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). 
         [0058]    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. 
         [0059]    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) or Ultra Wide Band (UWB) module.