Abstract:
The present invention relates to allocating a radio resource in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM). Preferably, the present invention comprises receiving in a mobile station data associated with a radio resource allocation map from a base station, wherein the radio allocation map comprises control parameters for transmitting an uplink channel, wherein the uplink channel comprises at least one OFDM tile comprising a first set of subcarriers associated with representing at least part of an n-bit data payload, and a second set of subcarriers associated with representing at least part of a non-pilot m-bit data payload wherein each subcarrier carries a modulated data, and the first and the second set of subcarriers are exclusive to each other, and transmitting the uplink channel from the mobile station to the base station.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/487,506, filed Jun. 18, 2009 now U.S. Pat. No. 7,768,903, issued Aug. 3, 2010, which is a continuation of U.S. application Ser. No. 11/319,251, filed Dec. 27, 2005, now U.S. Pat. No. 7,573,806, issued Aug. 11, 2009, which pursuant to 35 U.S.C. §119(a) claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2004-0112990, filed on Dec. 27, 2004, Korean Application No. 10-2005-0002266, filed on Jan. 10, 2005, and Korean Application No. 10-2005-0035405, filed on Apr. 28, 2005, the contents of which are hereby incorporated by reference herein in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a broadband wireless access system, and more particularly, to communicating a non-coherent detectable signal for use in an orthogonal frequency division multiplexing (OFDM) access system. 
     BACKGROUND OF THE INVENTION 
     In order to enable a plurality of users to simultaneously use limited radio resources, a multiplexing scheme is required. The multiplexing scheme divides a single line or transmission path into a plurality of channels capable of simultaneously transmitting/receiving individual independent signals. There are a variety of multiplexing schemes, for example, a Frequency Division Multiplexing (FDM) scheme for dividing a single line into a plurality of frequency bands and performing signal multiplexing, and a Time Division Multiplexing (TDM) scheme for dividing a single line into a plurality of very short time intervals and performing signal multiplexing. 
     Currently, due to the increasing demands of multimedia data in mobile communication, a multiplexing method for effectively transmitting a large amount of data is required. A representative multiplexing method is an orthogonal frequency division multiplexing (OFDM) scheme. 
     The OFDM scheme is indicative of a digital modulation scheme capable of improving a transfer rate per bandwidth and preventing multi-path interference from being generated. The OFDM scheme is characterized in that it acts as a multi-sub-carrier modulation scheme using a plurality of sub-carriers, wherein individual sub-carriers are orthogonal to each other. Therefore, although frequency components of individual sub-carriers overlap with each other, the OFDM scheme is problem free. The OFDM scheme can perform multiplexing of many more sub-carriers than those of a general frequency division multiplexing (FDM) scheme. Thus, high frequency use efficiency is implemented. 
     A mobile communication system based on the above-mentioned OFDM scheme currently uses a variety of multiple access schemes capable of allocating radio resources to a plurality of users, for example, an OFDM-FDMA (OFDMA) scheme, an OFDM-TDMA scheme, and an OFDM-CDMA scheme, etc. Specifically, the OFDMA (Orthogonal Frequency Division Multiple Access) scheme allocates some parts of all sub-carriers to individual users, such that it can accommodate a plurality of users. 
       FIG. 1  illustrates a method for allocating radio resources in accordance with the related art. Referring to  FIG. 1 , a broadband wireless access system comprises a specific configuration of  FIG. 1  as a basic unit for allocating OFDMA uplink radio resources. This specific configuration shown in  FIG. 1  is referred to as a tile structure. In the case of the above-mentioned tile structure, data of a Channel Quality Indication Channel (CQICH) or data of an Acknowledge Channel (ACKCH) is transmitted via a plurality of data sub-carriers  102 ,  103 ,  105 ,  106 ,  107 ,  108 ,  110 , and  111 . A pilot channel is transmitted via pilot sub-carriers  101 ,  104 ,  109 , and  112 . Each sub-carrier transmitted via the tile structure is referred to as a constituent unit of the tile structure. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to communicating a non-coherent detectable signal for use in an orthogonal frequency division multiplexing (OFDM) access system. 
     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the present invention is embodied in a method of allocating a radio resource in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM), the method comprising receiving in a mobile station data associated with a radio resource allocation map from a base station, wherein the radio allocation map comprises control parameters for transmitting an uplink channel, wherein the uplink channel comprises at least one OFDM tile comprising a first set of subcarriers associated with representing at least part of an n-bit data payload, and a second set of subcarriers associated with representing at least part of a non-pilot m-bit data payload wherein each subcarrier carries a modulated data, and the first and the second set of subcarriers are exclusive to each other, and transmitting the uplink channel from the mobile station to the base station. 
     Preferably, the uplink channel comprises a primary tile comprising the following Table 1A. 
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1A 
               
               
                   
                   
               
               
                   
                 Subcarrier 0 
                 Subcarrier 1 
                 Subcarrier 2 
                 Subcarrier 3 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Symbol 0 
                 NULL 
                 Mn, 8m 
                 Mn, 8m + 1 
                 NULL 
               
               
                 Symbol 1 
                 Mn, 8m + 2 
                 Mn, 8m + 3 
                 Mn, 8m + 4 
                 Mn, 8m + 5 
               
               
                 Symbol 2 
                 NULL 
                 Mn, 8m + 6 
                 Mn, 8m + 7 
                 NULL 
               
               
                   
               
             
          
         
       
     
     Table 1A can be depicted in a drawing format like  FIG. 10A , wherein an x-axis represents a time domain and a y-axis represents a frequency domain. 
     Preferably, the uplink channel further comprises a secondary tile comprising the following Table 1B. 
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1B 
               
               
                   
                   
               
               
                   
                 Subcarrier 0 
                 Subcarrier 1 
                 Subcarrier 2 
                 Subcarrier 3 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Symbol 0 
                 Mn, 4m 
                 NULL 
                 NULL 
                 Mn, 4m + 1 
               
               
                 Symbol 1 
                 NULL 
                 NULL 
                 NULL 
                 NULL 
               
               
                 Symbol 2 
                 Mn, 4m + 2 
                 NULL 
                 NULL 
                 Mn, 4m + 3 
               
               
                   
               
             
          
         
       
     
     Table 1B can be depicted in a drawing format like  FIG. 10B , wherein an x-axis represents a time domain and a y-axis represents a frequency domain. 
     In one aspect of the invention, information associated with the use of one of the first and the second sets of subcarriers is received in the mobile station using a normal map information element. 
     In another aspect of the invention, information associated with the use of one of the first and the second sets of subcarriers is received in the mobile station using a HARQ map information element. 
     Preferably, the first set of subcarriers is associated with representing at least part of a 6-bit data payload. Preferably, the second set of subcarriers is associated with representing at least part of a 4-bit data payload. 
     In a further aspect of the invention, the uplink channel is associated with transmitting one of channel quality information, antenna selection option and precoding matrix code book. 
     Preferably, the uplink channel is associated with transmitting one of fast down link measurement, MIMO mode, antenna grouping, antenna selection, reduced codebook, quantized precoding weight feedback, index to precoding matrix in codebook, channel matrix information and per stream power control. 
     Preferably, the use of the second set of subcarriers for transmitting at least part of the m-bit data payload is requested by one of the base station or the mobile station. 
     Preferably, six OFDM tiles comprise one OFDM slot for representing a 4-bit data payload, wherein the 4-bit data payload is represented as follows: 
     
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                   
                 Vector indices per tile 
               
               
                   
                   
                 Tile(0), Tile(1), 
               
               
                   
                 4 bit 
                 Tile(2), Tile(3), 
               
               
                   
                 payload 
                 Tile(4), Tile(5) 
               
               
                   
                   
               
             
             
               
                   
                 0b0000 
                 a, a, a, b, b, b 
               
               
                   
                 0b0001 
                 b, b, b, a, a, a 
               
               
                   
                 0b0010 
                 c, c, c, d, d, d 
               
               
                   
                 0b0011 
                 d, d, d, c, c, c 
               
               
                   
                 0b0100 
                 a, b, c, d, a, b 
               
               
                   
                 0b0101 
                 b, c, d, a, b, d 
               
               
                   
                 0b0110 
                 c, d, a, b, c, d 
               
               
                   
                 0b0111 
                 d, a, b, c, d, a 
               
               
                   
                 0b1000 
                 a, a, b, d, c, c 
               
               
                   
                 0b1001 
                 b, d, c, c, d, b 
               
               
                   
                 0b1010 
                 c, c, d, b, a, a 
               
               
                   
                 0b1011 
                 d, d, b, a, b, b 
               
               
                   
                 0b1100 
                 a, a, d, c, a, d 
               
               
                   
                 0b1101 
                 b, c, a, c, c, a 
               
               
                   
                 0b1110 
                 c, b, d, d, b, c 
               
               
                   
                 0b1111 
                 d, c, c, b, b, c 
               
               
                   
                   
               
             
          
         
       
     
     wherein 
     
       
         
               
               
             
           
               
                   
               
               
                 Vector Index 
                 M n,4m , M n,4m+1 , M n,4m+2 , M n,4m+3   
               
               
                   
               
             
             
               
                 A 
                 P0, P0, P0, P0 
               
               
                 B 
                 P0, P2, P0, P2 
               
               
                 C 
                 P0, P1, P2, P3 
               
               
                 D 
                 P1, P0, P3, P2 
               
               
                   
               
             
          
         
       
     
     In accordance with another embodiment of the present invention, a method of allocating a radio resource in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) comprises transmitting data associated with a radio resource allocation map to a mobile station, wherein the radio allocation map comprises control parameters for receiving an uplink channel, wherein the uplink channel comprises at least one OFDM tile comprising a first set of subcarriers associated with representing at least part of an n-bit data payload, and a second set of subcarriers associated with representing at least part of a non-pilot m-bit data payload wherein each subcarrier carries a modulated data, and the first and the second set of subcarriers are exclusive to each other, and receiving the uplink channel from the mobile station. 
     In accordance with another embodiment of the present invention, a mobile communication device for allocating a radio resource in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) comprises a receiver for receiving data associated with a radio resource allocation map from a base station, wherein the radio allocation map comprises control parameters for transmitting an uplink channel, wherein the uplink channel comprises at least one OFDM tile comprising a first set of subcarriers associated with representing at least part of an n-bit data payload, and a second set of subcarriers associated with representing at least part of a non-pilot m-bit data payload wherein each subcarrier carries a modulated data, and the first and the second set of subcarriers are exclusive to each other, and a transmitter for transmitting the uplink channel from the mobile communication device to the base station. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. Features, elements, and aspects of the invention that are referenced by the same numerals in different figures represent the same, equivalent, or similar features, elements, or aspects in accordance with one or more embodiments. 
         FIG. 1  illustrates a method for allocating radio resources in accordance with the related art. 
         FIG. 2  illustrates a method for allocating a CQICH (Channel Quality Indication Channel) area and an ACKCH (Acknowledge Channel) area in an OFDM uplink in accordance with one embodiment of the present invention. 
         FIG. 3  illustrates a tile structure for when a new signal is transmitted using a sub-carrier having transmitted a pilot signal in accordance with one embodiment of the present invention. 
         FIG. 4  illustrates a method for acquiring a secondary ACKCH from a CQICH tile structure in accordance with one embodiment of the present invention. 
         FIG. 5  illustrates a method for acquiring a secondary ACKCH from two ACKCH tile structures in accordance with one embodiment of the present invention. 
         FIG. 6  illustrates a method for acquiring a secondary CQICH from two CQICH tile structures in accordance with one embodiment of the present invention. 
         FIG. 7  illustrates a method for acquiring a secondary CQICH from four ACKCH tile structures in accordance with one embodiment of the present invention. 
         FIG. 8  illustrates a tile structure for use in a method for allocating a codeword using an additional sub-carrier in accordance with one embodiment of the present invention. 
         FIGS. 9A and 9B  illustrate a structure of a transmitter unit and receiver unit of a mobile communication device in accordance with one embodiment of the present invention. 
         FIGS. 10A and 10B  respectively illustrate an uplink channel primary tile and an uplink channel secondary tile, where the x-axis represents a time domain and a y-axis represents a frequency domain. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention relates to allocating a radio resource in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM). 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     Preferably, the present invention is applied to a broadband wireless access system, such as the system disclosed in IEEE 802.16e. However, it is contemplated that the present invention may be utilized in other types of wireless access systems. 
     Typically, channel estimation is performed on a data sub-carrier on the basis of the pilot sub-carrier, such that a coherent detection scheme is used for the data sub-carrier. However, an ACKCH or CQICH may use a non-coherent detection scheme without performing the channel estimation. In the meantime, the ACKCH or CQICH uses orthogonal codewords to implement a non-coherent detection scheme. 
     The following Table 1 exemplarily shows codewords for modulating ACKCH sub-carriers when ACK information of 1 bit is provided. 
     
       
         
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Vector indices per tile 
               
               
                 ACK 1-bit symbol 
                 Tile(0), Tile(1), Tile(2) 
               
               
                   
               
             
             
               
                 0 
                 0, 0, 0 
               
               
                 1 
                 4, 7, 2 
               
               
                   
               
             
          
         
       
     
     The following Table 2 exemplarily shows codewords for modulating CQICH sub-carriers when CQI information of 6 bits is provided. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                 Fast Feedback vector indices per 
               
               
                   
                 6-bit payload 
                 tile Tile(0), Tile(1), . . . , Tile(5) 
               
               
                   
                   
               
             
             
               
                   
                 0b000000 
                 0, 0, 0, 0, 0, 0 
               
               
                   
                 0b000001 
                 1, 1, 1, 1, 1, 1 
               
               
                   
                 0b000010 
                 2, 2, 2, 2, 2, 2 
               
               
                   
                 0b000011 
                 3, 3, 3, 3, 3, 3 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                   
               
             
          
         
       
     
     The following Table 3 exemplarily shows codewords for modulating CQICH sub-carriers when CQI information of 5 bits is provided. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                   
                 Fast Feedback vector indices per tile 
               
               
                   
                 5-bit payload 
                 Tile(0), Tile(1), . . . , Tile(5) 
               
               
                   
                   
               
             
             
               
                   
                 0b00000 
                 0, 0, 0, 0, 0 
               
               
                   
                 0b00001 
                 1, 1, 1, 1, 1 
               
               
                   
                 0b00010 
                 2, 2, 2, 2, 2 
               
               
                   
                 0b00011 
                 3, 3, 3, 3, 3 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                   
               
             
          
         
       
     
     The following Table 4 exemplarily shows codewords for modulating CQICH sub-carriers when CQI information of 4 bits is provided. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                   
                 Fast feedback vector indices per tile 
               
               
                   
                 4-bit payload 
                 Tile(0), Tile(1), . . . , Tile(5) 
               
               
                   
                   
               
             
             
               
                   
                 0b0000 
                 0, 0, 0, 0, 0, 0 
               
               
                   
                 0b0001 
                 1, 1, 1, 1, 1, 1 
               
               
                   
                 0b0010 
                 2, 2, 2, 2, 2, 2 
               
               
                   
                 0b0011 
                 3, 3, 3, 3, 3, 3 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                   
               
             
          
         
       
     
     With reference to Table 4, a vector for each tile includes 8 Quadrature Phase Shift Keying (QPSK) symbols, such that a signal can be transmitted via 8 data sub-carriers. 
     
       
         
               
               
             
           
               
                 TABLE 5 
               
               
                   
               
               
                 Vector Index 
                 M n,m8 , M n,8m+1 , . . . M n,8m+7   
               
               
                   
               
             
             
               
                 0 
                 P0, P1, P2, P3, P0, P1, P2, P3 
               
               
                 1 
                 P0, P3, P2, P1, P0, P3, P2, P1 
               
               
                 2 
                 P0, P0, P1, P1, P2, P2, P3, P3 
               
               
                 3 
                 P0, P0, P3, P3, P2, P2, P1, P1 
               
               
                 4 
                 P0, P0, P0, P0, P0, P0, P0, P0 
               
               
                 5 
                 P0, P2, P0, P2, P0, P2, P0, P2 
               
               
                 6 
                 P0, P2, P0, P2, P2, P0, P2, P0 
               
               
                 7 
                 P0, P2, P2, P0, P2, P0, P0, P2 
               
               
                   
               
             
          
         
       
     
     With reference to Table 5, P0, P1, P2, and P3 are denoted by the following Equation 1: 
     
       
         
           
             
               
                 
                   
                     
                       P 
                       0 
                     
                     = 
                     
                       exp 
                       ⁡ 
                       
                         ( 
                         
                           j 
                           ⁢ 
                           
                             π 
                             4 
                           
                         
                         ) 
                       
                     
                   
                   , 
                   
                     
 
                   
                   ⁢ 
                   
                     
                       P 
                       1 
                     
                     = 
                     
                       exp 
                       ⁡ 
                       
                         ( 
                         
                           j 
                           ⁢ 
                           
                             
                               3 
                               ⁢ 
                               π 
                             
                             4 
                           
                         
                         ) 
                       
                     
                   
                   , 
                   
                     
 
                   
                   ⁢ 
                   
                     
                       P 
                       2 
                     
                     = 
                     
                       exp 
                       ⁡ 
                       
                         ( 
                         
                           
                             - 
                             j 
                           
                           ⁢ 
                           
                             
                               3 
                               ⁢ 
                               π 
                             
                             4 
                           
                         
                         ) 
                       
                     
                   
                   , 
                   
                     
 
                   
                   ⁢ 
                   
                     
                       P 
                       3 
                     
                     = 
                     
                       exp 
                       ⁡ 
                       
                         ( 
                         
                           
                             - 
                             j 
                           
                           ⁢ 
                           
                             π 
                             4 
                           
                         
                         ) 
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
     A single sub-channel includes 6 tiles. The CQICH can use a single sub-channel, and the ACKCH can use half of the sub-channel. In other words, the CQICH can use 6 tiles, and the ACKCH can use 3 tiles. 
       FIG. 2  illustrates a method for allocating a CQICH (Channel Quality Indication Channel) area and an ACKCH (Acknowledge Channel) area in an OFDM uplink in accordance with one embodiment of the present invention. Referring to  FIG. 2 , some areas of a two-dimensional map of an uplink are pre-assigned to the ACKCH dedicated area  201 , and the remaining areas other than the above-mentioned areas are pre-assigned to the CQICH dedicated area  202 . 
     Individual sub-channels are assigned to an ACKCH dedicated area  201  and a CQICH dedicated area  202 , such that a specific Mobile Subscriber Station (MSS) can use the ACKCH dedicated area  201  and the CQICH dedicated area  202 . Referring to  FIG. 2 , an MSS# 1  may be assigned to an ACK# 1 , an MSS# 2  may be assigned to an ACK# 2 , . . . , an MSS# 8  may be assigned to an ACK# 8 , an MSS# 9  may be assigned to a CQICH# 1 , an MSS# 10  may be assigned to a CQICH# 2  and a CQICH# 3 , and an MSS# 11  may be assigned to a CQICH# 4 . 
     If a base station uses a non-coherent detection scheme, there is no need to use pilot sub-carriers. In this case, it is not necessary to use 4 pilot sub-carriers assigned to each tile, and the uplink&#39;s radio resources and terminal&#39;s transmission power are unnecessarily consumed. 
     Therefore, new information is loaded on a sub-carrier assigned to a pilot channel, and is then transmitted to the CQICH and ACKCH tile structures, such that specific information based on the non-coherent detection scheme in the same manner as in the CQICH or ACKCH can be transmitted using a conventional sub-carrier equipped with a pilot signal. 
       FIG. 3  illustrates a tile structure for when a new signal is transmitted using a sub-carrier having transmitted a pilot signal in accordance with one embodiment of the present invention. Referring to  FIG. 3 , a new signal can be transmitted using sub-carriers  301 ,  304 ,  309 , and  312 . These sub-carriers used to transmit a pilot signal. 
     As stated above, if the new signal is loaded on the sub-carrier having transmitted the pilot signal in the tile structure for the CQICH and the ACKCH, the sub-carrier having transmitted each pilot signal is referred to as an additional sub-carrier. If the additional sub-carrier formed by the grouping of unit tile structures is used, a secondary CQICH and a secondary ACKCH other than a primary ACKCH and a primary CQICH can be acquired. 
       FIG. 4  illustrates a method for acquiring a secondary CQICH from a CQICH tile structure in accordance with one embodiment of the present invention. Referring to  FIG. 4 , a single CQICH includes 6 tile units (1 subchannel), wherein 4 additional sub-carriers may be acquired from each tile unit, such that a total of 24 additional sub-carriers may be acquired from each CQICH. Meanwhile, an ACKCH or a secondary CQICH may include 3 tile units (1/2 subchannel), wherein each tile unit includes 8 sub-carriers, such that a single ACKCH or a secondary CQICH may be constructed using 24 sub-carriers. Therefore, a single ACKCH (i.e., the secondary ACKCH) or a secondary CQICH may be constructed using 24 additional sub-carriers capable of being acquired from a single CQICH. 
       FIG. 5  illustrates a method for acquiring a secondary ACKCH from two ACKCH tile structures in accordance with one embodiment of the present invention. Referring to  FIG. 5 , a single ACKCH may include 3 tile units, wherein 4 additional sub-carriers may be acquired from each tile unit, such that a total of 24 additional sub-carriers can be acquired from two ACKCHs. Meanwhile, a single ACKCH may be constructed using 24 sub-carriers, such that a single ACKCH (i.e., the secondary ACKCH) can be constructed when additional sub-carriers are acquired from a group comprising 2 ACKCHs, as shown in  FIG. 5 . 
       FIG. 6  illustrates a method for acquiring a secondary CQICH from two CQICH tile structures in accordance with one embodiment of the present invention. Referring to  FIG. 6 , each CQICH may include 6 tile units, wherein 4 additional sub-carriers are acquired from each tile unit, such that a total of 48 additional sub-carriers may be acquired from two CQICHs. Meanwhile, a CQICH may also include 6 tile units, wherein each tile unit includes 8 sub-carriers, such that a single CQICH may be constructed using 48 sub-carriers. Therefore, a single CQICH (i.e., the secondary CQICH) may be constructed using 48 additional sub-carriers capable of being acquired from two CQICHs. 
       FIG. 7  illustrates a method for acquiring a secondary CQICH from four ACKCH tile structures in accordance with one embodiment of the present invention. Referring to  FIG. 7 , a single ACKCH may include 3 tile units, wherein 4 additional sub-carriers may be acquired from each tile unit, such that a total of 48 additional sub-carriers may be acquired from 4 ACKCHs. Meanwhile, a CQICH may include 6 tile units, wherein each tile unit includes 8 sub-carriers, such that a single CQICH may be constructed using 48 sub-carriers. Therefore, a single CQICH (i.e., the secondary CQICH) may be constructed using 48 additional sub-carriers capable of being acquired from 4 ACKCHs. 
     Preferably, the following methods can be adapted to assign a codeword to a sub-carrier. According to a first preferred embodiment of the present invention, 12 tiles contained in either a single CQICH or two ACKCHs are grouped into 6 sets, each of which comprises 2 tiles, and the codeword can be assigned, as shown in the following Tables 6-9. 
     The following Table 6 exemplarily shows a method for assigning a codeword to modulate a secondary ACKCH sub-carrier when ACK information of 1 bit is provided. 
     
       
         
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                   
                 Vector indices per tile 
               
               
                 Additional ACKCH 1- 
                 (Tile(0), Tile(1)), (Tile(2), 
               
               
                 bit symbol 
                 Tile(3)), (Tile(4), Tile(5)) 
               
               
                   
               
             
             
               
                 0 
                 0, 0, 0 
               
               
                 1 
                 4, 7, 2 
               
               
                   
               
             
          
         
       
     
     The following Table 7 exemplarily shows a method for assigning a codeword to modulate a CQICH sub-carrier when CQI information of 6 bits is provided. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 7 
               
               
                   
                   
               
               
                   
                   
                 Fast Feedback vector indices per tile 
               
               
                   
                 6-bits 
                 (Tile(0), Tile(1)), (Tile(2), Tile(3)), 
               
               
                   
                 payload 
                 (Tile(4), Tile(5)), . . . (Tile(10), Tile(11)) 
               
               
                   
                   
               
             
             
               
                   
                 0b000000 
                 0, 0, 0, 0, 0, 0 
               
               
                   
                 0b000001 
                 1, 1, 1, 1, 1, 1 
               
               
                   
                 0b000010 
                 2, 2, 2, 2, 2, 2 
               
               
                   
                 0b000011 
                 3, 3, 3, 3, 3, 3 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                   
               
             
          
         
       
     
     The following Table 8 exemplarily shows a codeword for modulating a CQICH sub-carrier when CQI information of 5 bits is provided. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 8 
               
               
                   
                   
               
               
                   
                   
                 Fast Feedback vector indices per tile 
               
               
                   
                   
                 (Tile(0), Tile(1)), (Tile(2), Tile(3)), (Tile(4), 
               
               
                   
                 5-bits payload 
                 Tile(5)), . . . (Tile(10), Tile(11)) 
               
               
                   
                   
               
             
             
               
                   
                 0b00000 
                 0, 0, 0, 0, 0 
               
               
                   
                 0b00001 
                 1, 1, 1, 1, 1 
               
               
                   
                 0b00010 
                 2, 2, 2, 2, 2 
               
               
                   
                 0b00011 
                 3, 3, 3, 3, 3 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                   
               
             
          
         
       
     
     The following Table 9 exemplarily shows a codeword for modulating a CQICH sub-carrier when CQI information of 4 bits is provided. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 9 
               
               
                   
                   
               
               
                   
                   
                 Fast Feedback vector indices per tile 
               
               
                   
                   
                 (Tile(0), Tile(1)), (Tile(2), Tile(3)), 
               
               
                   
                 4-bits payload 
                 (Tile(4), Tile(5)), . . . (Tile(10), Tile(11)) 
               
               
                   
                   
               
             
             
               
                   
                 0b00000 
                 0, 0, 0, 0, 0, 0 
               
               
                   
                 0b00001 
                 1, 1, 1, 1, 1, 1 
               
               
                   
                 0b00010 
                 2, 2, 2, 2, 2, 2 
               
               
                   
                 0b00011 
                 3, 3, 3, 3, 3, 3 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                 . 
                 . 
               
               
                   
                   
               
             
          
         
       
     
     Meanwhile, according to a second preferred embodiment of the present invention, a codeword can be assigned to each of 12 tiles contained in either a single CQICH or two ACKCHs, as shown in the following Tables 10-11. 
     The following Table 10 exemplarily shows a method for assigning a codeword to modulate a secondary ACKCH sub-carrier when ACK information of 1 bit is provided. 
     
       
         
               
               
             
           
               
                 TABLE 10 
               
               
                   
               
               
                 additional ACK 
                 Vector indices per tile 
               
               
                 1-bit symbol 
                 Tile(0), Tile(1), Tile(2), Tile(3), Tile(4), Tile(5) 
               
               
                   
               
             
             
               
                 0 
                 a, a, a, a, a, a 
               
               
                 1 
                 b, b, b, b, b, b 
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
             
           
               
                 TABLE 11 
               
               
                   
               
               
                 additional 
                 Fast Feedback vector indices per tile 
               
               
                 CQICH 6-bits, 5-bits and 
                 Tile(0), Tile(1), Tile(2), Tile(3), Tile(4), 
               
               
                 4-bits payload 
                 Tile(5), . . . Tile(10), Tile(11) 
               
               
                   
               
             
             
               
                 0b000000, 0b00000, 0b0000 
                 a, a, a, a, a, a, a, a, a, a, a, a 
               
               
                 0b000001, 0b00001, 0b0001 
                 b, b, b, b, b, b, b, b, b, b, b, b 
               
               
                 0b000010, 0b00001, 0b0001 
                 c, c, c, c, c, c, c, c, c, c, c, c 
               
               
                 0b000011, 0b00011, 0b0011 
                 d, d, d, d, d, d, d, d, d, d, d, d 
               
               
                   
               
             
          
         
       
     
     Additional sub-carriers of the tile applied to the codeword allocation shown in Table 11 are depicted in  FIG. 8 . 
       FIG. 8  illustrates a tile structure for use in a method for allocating a codeword using an additional sub-carrier in accordance with one embodiment of the present invention. 
     Referring to  FIG. 8  and the following Table 12, a vector assigned to each tile includes 4 modulation symbols in order to perform signal transmission via 4 additional sub-carriers. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 12 
               
               
                   
                   
               
               
                   
                 Vector Index 
                 M n,4m , M n,4m+1 , M n,4m+2 , M n,4m+3   
               
               
                   
                   
               
             
             
               
                   
                 a 
                 P0, P0, P0, P0 
               
               
                   
                 b 
                 P0, P2, P0, P2 
               
               
                   
                 c 
                 P0, P1, P2, P3 
               
               
                   
                 d 
                 P1, P0, P3, P2 
               
               
                   
                   
               
             
          
         
       
     
     The secondary ACKCH can be constructed using 24 sub-carriers assigned to a pilot channel. A method for constructing the ACKCH using the 24 pilot sub-carriers can be implemented with additional sub-carriers in various ways other than exemplary methods shown in  FIGS. 9-10 . 
     The secondary ACKCH can be configured using 3 tiles. The following Table 13 exemplarily shows a codeword available for the above-mentioned case in which the secondary ACKCH includes 3 tiles. 
     
       
         
               
               
             
           
               
                 TABLE 13 
               
               
                   
               
               
                 Secondary ACK 
                   
               
               
                 1-bit symbol 
                 Vector indices per tile Tile(0), Tile(1), Tile(2) 
               
               
                   
               
             
             
               
                 0 
                 a, a, a 
               
               
                 1 
                 b, b, b 
               
               
                   
               
             
          
         
       
     
     The secondary CQICH can be constructed using 48 pilot sub-carriers. A method for constructing the ACKCH using the 48 pilot sub-carriers can be implemented with additional sub-carriers in various ways other than the exemplary methods shown in  FIGS. 6-7 . 
     The secondary CQICH can be configured using 6 tiles. The following Table 14 exemplarily shows a codeword available for the above-mentioned case in which the secondary CQICH includes 6 tiles. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 14 
               
               
                   
                   
               
               
                   
                   
                 Vector indices per tile 
               
               
                   
                 Secondary CQICH 
                 Tile(0), Tile(1), 
               
               
                   
                 4 bit 
                 Tile(2), Tile(3), 
               
               
                   
                 payload 
                 Tile(4), Tile(5) 
               
               
                   
                   
               
             
             
               
                   
                 0b0000 
                 a, a, a, b, b, b 
               
               
                   
                 0b0001 
                 b, b, b, a, a, a 
               
               
                   
                 0b0010 
                 c, c, c, d, d, d 
               
               
                   
                 0b0011 
                 d, d, d, c, c, c 
               
               
                   
                 0b0100 
                 a, b, c, d, a, b 
               
               
                   
                 0b0101 
                 b, c, d, a, b, d 
               
               
                   
                 0b0110 
                 c, d, a, b, c, d 
               
               
                   
                 0b0111 
                 d, a, b, c, d, a 
               
               
                   
                 0b1000 
                 a, a, b, d, c, c 
               
               
                   
                 0b1001 
                 b, d, c, c, d, b 
               
               
                   
                 0b1010 
                 c, c, d, b, a, a 
               
               
                   
                 0b1011 
                 d, d, b, a, b, b 
               
               
                   
                 0b1100 
                 a, a, d, c, a, d 
               
               
                   
                 0b1101 
                 b, c, a, c, c, a 
               
               
                   
                 0b1110 
                 c, b, d, d, b, c 
               
               
                   
                 0b1111 
                 d, c, c, b, b, c 
               
               
                   
                   
               
             
          
         
       
     
     Meanwhile, a new codeword can be constructed using binary phase-shift keying (BPSK), as shown in the following Table 15. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 15 
               
               
                   
                   
               
               
                   
                 Vector Index 
                 M n,4m , M n,4m+1 , M n,4m+2 , M n,4m+3   
               
               
                   
                   
               
             
             
               
                   
                 a 
                 1, 1, 1, 1 
               
               
                   
                 b 
                 1, −1, 1, −1 
               
               
                   
                 c 
                 1, 1, −1, −1 
               
               
                   
                 d 
                 1, −1, −1, 1 
               
               
                   
                   
               
             
          
         
       
     
     A base station can use messages shown in the following Table 16 to inform a mobile subscriber station (MSS) of information associated with the secondary ACKCH. 
     
       
         
               
               
               
             
           
               
                 TABLE 16 
               
               
                   
               
               
                 Syntax 
                 Size(bits) 
                 Notes 
               
               
                   
               
             
             
               
                 Compact_UL_MAP_IE( ){ 
                   
                   
               
               
                  UL-MAP Type 
                 3 
                 Type = 7 
               
               
                  UL-MAP Sub-type 
                 5 
                 Sub-type = 3 
               
               
                  Length 
                 4 
                 Length of the IE 
               
               
                   
                   
                 bytes 
               
               
                  Primary/Secondary H-ARQ Region 
                 1 
                 0 = no region 
               
               
                 Change Indication 
                   
                 change 
               
               
                   
                   
                 1 = region change 
               
               
                  If(Primary/Secondary H-ARQ Region 
               
               
                   Change indication==1){ 
               
               
                   OFDMA Symbol Offset 
                 8 
               
               
                   Subchannel Offset 
                 8 
               
               
                   No. OFDMA Symbols 
                 8 
               
               
                   No. Subchannels 
                 8 
               
               
                  } 
               
               
                  Reserved 
                 3 
               
               
                  } 
               
               
                   
               
             
          
         
       
     
     With reference to Table 16, the “UL-MAP TYPE” field and the “Sub-Type” field are adapted to inform an MSS of message type information. In other words, the MSS can recognize content information of a corresponding message by referring to the above-mentioned “UL-MAP TYPE” and “Sub-Type” fields. Meanwhile, the “Length” field informs the MSS of size information of overall messages including the “Length” field in byte units. 
     The “Primary/Secondary H-ARQ Region Indication” field has a value of 1 either when a current frame has an H-ARQ region different from that of a previous frame or when another H-ARQ region is present in the same frame. The “OFDMA Symbol Offset” field informs the MSS of coordinates at which the “H-ARQ” region begins at an uplink in symbol units. The “Subchannel Offset” field informs the MSS of coordinates at which the “H-ARQ” region begins at an uplink in sub-channel units. The “No. OFDMA symbols” field informs the MSS of size information occupied by the “H-ARQ” region at an uplink in symbol units. The “No. Sub-channels” field informs the MSS of size information occupied by the “H-ARQ” region at an uplink in subchannel units. 
     Meanwhile, a base station may use messages shown in the following Table 17 to inform the MSS of information associated with the secondary CQICH. 
     
       
         
               
               
               
             
           
               
                 TABLE 17 
               
               
                   
               
               
                 Syntax 
                 Size(bits) 
                 Notes 
               
               
                   
               
             
             
               
                 Compact_UL_MAP_IE( ){ 
                   
                   
               
               
                  UL-MAP Type 
                 3 
                 Type = 7 
               
               
                  UL-MAP Sub-type 
                 5 
                 Sub-type = 3 
               
               
                  Length 
                 4 
                 Length of the IE bytes 
               
               
                  Primary/Secondary H-ARQ Region 
                 1 
                 0 = no region change 
               
               
                 Change Indication 
               
               
                 If(Primary/Secondary H-ARQ Region 
                   
                 1 = region change 
               
               
                 Change indication==1){ 
               
               
                   OFDMA Symbol Offset 
                 8 
               
               
                   Subchannel Offset 
                 8 
               
               
                   No. OFDMA Symbols 
                 8 
               
               
                   No. Subchannels 
                 8 
               
               
                  } 
               
               
                  Reserved 
                 3 
               
               
                  } 
               
               
                   
               
             
          
         
       
     
     With reference to Table 17, the “UL-MAP TYPE” field and the “Sub-Type” field are adapted to inform the MSS of message type information. In other words, the MSS can recognize message content information by referring to the above-mentioned “UL-MAP TYPE” and “Sub-Type” fields. Meanwhile, the “Length” field informs the MSS of size information of overall messages including the “Length” field in byte units. 
     The “Primary/Secondary CQICH Region Indication” field has a value of 1 either when a current frame has a CQICH region different from that of a previous frame or when another CQICH region is present in the same frame. The “OFDMA Symbol Offset” field informs the MSS of coordinates at which the “CQICH” region begins at an uplink in symbol units. The “Subchannel Offset” field informs the MSS of coordinates at which the “CQICH” region begins at an uplink in subchannel units. The “No. OFDMA symbols” field informs the MSS of size information occupied by the “CQICH” region at an uplink in symbol units. The “No. Sub-channels” field informs the MSS of size information occupied by the “CQICH” region at an uplink in subchannel units. 
     Information transmitted via the secondary CQICH according to the present invention can be used in various ways according to feedback types. For example, if information associated with a Signal-to-Noise Ratio (SNR) is transmitted to the base station, a payload of the above-mentioned information may occur as depicted in the following Equation 2: 
     
       
         
           
             
               
                 
                   
                     4 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     bit 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     payload 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     bit 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     nibble 
                   
                   = 
                   
                     { 
                     
                       
                         
                           
                             0 
                             , 
                           
                         
                         
                           
                             
                               S 
                               / 
                               N 
                             
                             &lt; 
                             
                               
                                 - 
                                 2 
                               
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               dB 
                             
                           
                         
                         
                           
                               
                           
                         
                       
                       
                         
                           
                             n 
                             , 
                           
                         
                         
                           
                             
                               
                                 
                                   2 
                                   ⁢ 
                                   n 
                                 
                                 - 
                                 4 
                               
                               &lt; 
                               
                                 S 
                                 / 
                                 N 
                               
                               &lt; 
                               
                                 
                                   2 
                                   ⁢ 
                                   n 
                                 
                                 - 
                                 2 
                               
                             
                             , 
                           
                         
                         
                           
                             0 
                             &lt; 
                             n 
                             &lt; 
                             15 
                           
                         
                       
                       
                         
                           
                             15 
                             , 
                           
                         
                         
                           
                             
                               S 
                               / 
                               N 
                             
                             &gt; 
                             
                               26 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               dB 
                             
                           
                         
                         
                           
                               
                           
                         
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     2 
                   
                   ] 
                 
               
             
           
         
       
     
     Meanwhile, in the case of a Multi-Input Multi-Output (MIMO) mode, a payload depicted in the following Table 18 may occur. 
     
       
         
               
               
             
           
               
                 TABLE 18 
               
               
                   
               
               
                 Value 
                 Description 
               
               
                   
               
             
             
               
                 0b0000 
                 STTD and PUSC/FUSC permutation 
               
               
                 0b0001 
                 STTD and adjacent-subcarrier permutation 
               
               
                 0b0010 
                 SM and PUSC/FUSC permutation 
               
               
                 0b0011 
                 SM and adjacent-subcarrier permutation 
               
               
                 0b0100 
                 Closed-loop SM and PUSC/FUSC permutation 
               
               
                 0b0101 
                 Closed-loop SM and adjacent-subcarrier permutation 
               
               
                 0b0110 
                 Closed-loop SM + Beamforming and adjacent-subcarrier 
               
               
                   
                 permutation 
               
               
                 0b0111-0b1111 
                 Interpretation according to table 296e, 296f or 296g, 
               
               
                   
                 depending on if antenna grouping, antenna selection or 
               
               
                   
                 a reduced precoding matrix code book is used. 
               
               
                   
               
             
          
         
       
     
     The following Table 19 exemplarily shows antenna grouping methods corresponding to individual values shown in Table 18. 
     
       
         
               
               
             
           
               
                 TABLE 19 
               
               
                   
               
               
                 Value 
                 Description 
               
               
                   
               
             
             
               
                 0b0111 
                 Antenna Group A1 for rate 1 
               
               
                   
                 For 3-antenna BS, See 8.4.8.3.4 
               
               
                   
                 For 4-antenna BS, See 8.4.8.3.5 
               
               
                 0b1000 
                 Antenna Group A2 for rate 1 
               
               
                 0b1001 
                 Antenna Group A3 for rate 1 
               
               
                 0b1010 
                 Antenna Group B1 for rate 2 
               
               
                   
                 For 3-antenna BS, See 8.4.8.3.4 
               
               
                   
                 For 4-antenna BS, See 8.4.8.3.5 
               
               
                 0b1011 
                 Antenna Group B2 for rate 2 
               
               
                 0b1100 
                 Antenna Group B3 for rate 2 
               
               
                 0b1101 
                 Antenna Group B4 for rate 2 (only for 4-antenna BS) 
               
               
                 0b1110 
                 Antenna Group B5 for rate 2 (only for 4-antenna BS) 
               
               
                 0b1111 
                 Antenna Group B6 for rate 2 (only for 4-antenna BS) 
               
               
                   
               
             
          
         
       
     
     The following Table 20 exemplarily shows antenna selection methods corresponding to individual values shown in Table 18. 
     
       
         
               
               
             
           
               
                 TABLE 20 
               
               
                   
               
               
                 Value 
                 Description 
               
               
                   
               
             
             
               
                 0b0111 
                 Antenna selection option 0 
               
               
                 0b1000 
                 Antenna selection option 1 
               
               
                 0b1001 
                 Antenna selection option 2 
               
               
                 0b1010 
                 Antenna selection option 3 
               
               
                 0b1011 
                 Antenna selection option 4 
               
               
                 0b1100 
                 Antenna selection option 5 
               
               
                 0b1101 
                 Antenna selection option 6 
               
               
                 0b1110 
                 Antenna selection option 7 
               
               
                 0b1111 
                 Reserved 
               
               
                   
               
             
          
         
       
     
     The following Table 21 exemplarily shows a method for employing reduced precoding matrix code books corresponding to individual values shown in Table 18. 
     
       
         
               
               
             
           
               
                 TABLE 21 
               
               
                   
               
               
                 Value 
                 Description 
               
               
                   
               
             
             
               
                 0b0111 
                 Reduced Precoding matrix code book entry 0 
               
               
                 0b1000 
                 Reduced Precoding matrix code book entry 1 
               
               
                 0b1001 
                 Reduced Precoding matrix code book entry 2 
               
               
                 0b1010 
                 Reduced Precoding matrix code book entry 3 
               
               
                 0b1011 
                 Reduced Precoding matrix code book entry 4 
               
               
                 0b1100 
                 Reduced Precoding matrix code book entry 5 
               
               
                 0b1101 
                 Reduced Precoding matrix code book entry 6 
               
               
                 0b1110 
                 Reduced Precoding matrix code book entry 7 
               
               
                 0b1111 
                 Reserved 
               
               
                   
               
             
          
         
       
     
     The base station transmits information associated with the above-mentioned feedback type information to an MSS via a “CQICH_Enhanced_Alloc_IE” field. 
     The following Tables 22 and 23 exemplarily show some parts of the “CQICH_Enhanced_Alloc_IE” field including the above-mentioned feedback type information. 
     
       
         
               
               
               
             
           
               
                 TABLE 22 
               
               
                   
               
             
             
               
                 CQICH_Enhanced_Alloc_IE( ){ 
                   
                   
               
               
                 . . . 
                 . . . 
                 . . . 
               
               
                 Feedback type 
                 3 bits 
                 0b000 = Fast DL Measurement 
               
               
                   
                   
                 0b001 = MIMO Mode selection/Antenna Grouping 
               
               
                   
                   
                 0b010 = MIMO Mode selection/Antenna Selection 
               
               
                   
                   
                 0b011 = MIMO Mode Selection/Reduced Codebook 
               
               
                   
                   
                 0b100 = Quantized Precoding Weight Feedback 
               
               
                   
                   
                 0b101 = Index to Precoding Matrix in Codebook 
               
               
                   
                   
                 0b110 = Channel Matrix Information 
               
               
                   
                   
                 0b111 = Per Stream Power Control 
               
               
                 . . . 
                 . . . 
                 . . . 
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
               
             
           
               
                 TABLE 23 
               
               
                   
               
             
             
               
                 CQICH_Enhanced_Alloc_IE( ){ 
                   
                   
               
               
                 ... 
                 ... 
                 ... 
               
               
                 Feedback type 
                 3 bits 
                 0b000 = Fast DL measurement/Antenna grouping 
               
               
                   
                   
                 for 6bit payload 
               
               
                   
                   
                 = Fast DL measurement for 4bit payload 
               
               
                   
                   
                 0b001 = Fast DL measurement/Antenna selection 
               
               
                   
                   
                 for 6bit payload 
               
               
                   
                   
                 = MIMO mode/Antenna grouping for 4bit 
               
               
                   
                   
                 payload 
               
               
                   
                   
                 0b010 = Fast DL measurement/Reduced codebook 
               
               
                   
                   
                 for 6bit payload 
               
               
                   
                   
                 = Antenna selection/Reduced Codebook for 
               
               
                   
                   
                 4bit payload 
               
               
                   
                   
                 0b011 = Quantized precoding weight feedback 
               
               
                   
                   
                 0b100 = Index to precoding matrix in codebook 
               
               
                   
                   
                 0b101 = Channel Matrix Information 
               
               
                   
                   
                 0b110 = Per stream power control 
               
               
                   
                   
                 0b111 = reserved 
               
               
                   
               
             
          
         
       
     
     Meanwhile, if only information associated with the SNR is transmitted to the base station, a payload of information transmitted via the secondary CQICH according to the present invention may occur as depicted in the following Equation 3: 
     
       
         
           
             
               
                 
                   
                     4 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     bit 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     payload 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     bit 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     nibble 
                   
                   = 
                   
                     { 
                     
                       
                         
                           
                             0 
                             , 
                           
                         
                         
                           
                             
                               S 
                               / 
                               N 
                             
                             &lt; 
                             
                               
                                 - 
                                 2 
                               
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               dB 
                             
                           
                         
                         
                           
                               
                           
                         
                       
                       
                         
                           
                             n 
                             , 
                           
                         
                         
                           
                             
                               
                                 
                                   2 
                                   ⁢ 
                                   n 
                                 
                                 - 
                                 4 
                               
                               &lt; 
                               
                                 S 
                                 / 
                                 N 
                               
                               &lt; 
                               
                                 
                                   2 
                                   ⁢ 
                                   n 
                                 
                                 - 
                                 2 
                               
                             
                             , 
                           
                         
                         
                           
                             0 
                             &lt; 
                             n 
                             &lt; 
                             15 
                           
                         
                       
                       
                         
                           
                             15 
                             , 
                           
                         
                         
                           
                             
                               S 
                               / 
                               N 
                             
                             &gt; 
                             
                               26 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               dB 
                             
                           
                         
                         
                           
                               
                           
                         
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     3 
                   
                   ] 
                 
               
             
           
         
       
     
     Information associated with feedback types capable of transmitting only SNR-associated information to the base station is transmitted to the MSS via the “CQICH_Enhanced_Alloc_IE” field. 
     The following Table 24 exemplarily shows some parts of the “CQICH_Enhanced_Alloc_IE” field including the above-mentioned feedback type information. 
     
       
         
               
               
               
             
           
               
                 TABLE 24 
               
               
                   
               
             
             
               
                 CQICH_Enhanced_Alloc_IE( ){ 
                   
                   
               
               
                 ... 
                 ... 
                 ... 
               
               
                 Feedback type 
                 3 bits 
                 0b000 = Fast DL measurement/Antenna 
               
               
                   
                   
                 grouping for 6bit payload 
               
               
                   
                   
                 = Fast DL measurement for 4bit 
               
               
                   
                   
                 payload 
               
               
                   
                   
                 0b001 = Fast DL measurement/Antenna 
               
               
                   
                   
                 selection for 6bit payload 
               
               
                   
                   
                 = Fast DL measurement for 4bit payload 
               
               
                   
                   
                 0b010 = Fast DL measurement/Reduced 
               
               
                   
                   
                 codebook for 
               
               
                   
                   
                 6bit payload 
               
               
                   
                   
                 = Fast DL measurement for 4bit payload 
               
               
                   
                   
                 0b011 = Quantized precoding weight 
               
               
                   
                   
                 feedback 
               
               
                   
                   
                 0b100 = Index to precoding matrix in codebook 
               
               
                   
                   
                 0b101 = Channel Matrix Information 
               
               
                   
                   
                 0b110 = Per stream power control 
               
               
                   
                   
                 0b111 = reserved 
               
               
                 ... 
                 ... 
                 ... 
               
               
                   
               
             
          
         
       
     
     Meanwhile, information transmitted via the secondary CQICH can be used in various ways according to feedback types. In other words, the above-mentioned secondary CQICH can be used only for MIMO mode selection. If the secondary CQICH is used only for the MIMO mode selection, a payload may occur as shown in the following Table 25. 
     
       
         
               
               
             
           
               
                 TABLE 25 
               
               
                   
               
               
                 Value 
                 Description 
               
               
                   
               
             
             
               
                 0b0000 
                 STTD and PUSC/FUSC permutation 
               
               
                 0b0001 
                 STTD and adjacent-subcarrier permutation 
               
               
                 0b0010 
                 SM and PUSC/FUSC permutation 
               
               
                 0b0011 
                 SM and adjacent-subcarrier permutation 
               
               
                 0b0100 
                 Closed-loop SM and PUSC/FUSC permutation 
               
               
                 0b0101 
                 Closed-loop SM and adjacent-subcarrier permutation 
               
               
                 0b0110 
                 Closed-loop SM + Beamforming and adjacent-subcarrier 
               
               
                   
                 permutation 
               
               
                 0b0111-0b1111 
                 Interpretation according to table 296e, 296f or 296g, 
               
               
                   
                 depending on if antenna grouping, antenna selection or a 
               
               
                   
                 reduced precoding matrix code book is used. 
               
               
                   
               
             
          
         
       
     
     The following Table 26 exemplarily shows antenna grouping methods corresponding to individual values shown in Table 25. 
     
       
         
               
               
             
           
               
                 TABLE 26 
               
               
                   
               
               
                 Value 
                 Description 
               
               
                   
               
             
             
               
                 0b0111 
                 Antenna Group A1 for rate 1 
               
               
                   
                 For 3-antenna BS, See 8.4.8.3.4 
               
               
                   
                 For 4-antenna BS, See 8.4.8.3.5 
               
               
                 0b1000 
                 Antenna Group A2 for rate 1 
               
               
                 0b1001 
                 Antenna Group A3 for rate 1 
               
               
                 0b1010 
                 Antenna Group B1 for rate 2 
               
               
                   
                 For 3-antenna BS, See 8.4.8.3.4 
               
               
                   
                 For 4-antenna BS, See 8.4.8.3.5 
               
               
                 0b1011 
                 Antenna Group B2 for rate 2 
               
               
                 0b1100 
                 Antenna Group B3 for rate 2 
               
               
                 0b1101 
                 Antenna Group B4 for rate 2 (only for 4-antenna BS) 
               
               
                 0b1110 
                 Antenna Group B5 for rate 2 (only for 4-antenna BS) 
               
               
                 0b1111 
                 Antenna Group B6 for rate 2 (only for 4-antenna BS) 
               
               
                   
               
             
          
         
       
     
     The following Table 27 exemplarily shows antenna grouping methods corresponding to individual values shown in Table 25. 
     
       
         
               
               
             
           
               
                 TABLE 27 
               
               
                   
               
               
                 Value 
                 Description 
               
               
                   
               
             
             
               
                 0b0111 
                 Antenna selection option 0 
               
               
                 0b1000 
                 Antenna selection option 1 
               
               
                 0b1001 
                 Antenna selection option 2 
               
               
                 0b1010 
                 Antenna selection option 3 
               
               
                 0b1011 
                 Antenna selection option 4 
               
               
                 0b1100 
                 Antenna selection option 5 
               
               
                 0b1101 
                 Antenna selection option 6 
               
               
                 0b1110 
                 Antenna selection option 7 
               
               
                 0b1111 
                 Reserved 
               
               
                   
               
             
          
         
       
     
     The following Table 28 exemplarily shows a method for employing reduced precoding matrix code books corresponding to individual values shown in Table 25. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 28 
               
               
                   
                   
               
               
                   
                 Value 
                 Description 
               
               
                   
                   
               
             
             
               
                   
                 0b0111 
                 Reduced Precoding matrix code book entry 0 
               
               
                   
                 0b1000 
                 Reduced Precoding matrix code book entry 1 
               
               
                   
                 0b1001 
                 Reduced Precoding matrix code book entry 2 
               
               
                   
                 0b1010 
                 Reduced Precoding matrix code book entry 3 
               
               
                   
                 0b1011 
                 Reduced Precoding matrix code book entry 4 
               
               
                   
                 0b1100 
                 Reduced Precoding matrix code book entry 5 
               
               
                   
                 0b1101 
                 Reduced Precoding matrix code book entry 6 
               
               
                   
                 0b1110 
                 Reduced Precoding matrix code book entry 7 
               
               
                   
                 0b1111 
                 Reserved 
               
               
                   
                   
               
             
          
         
       
     
     The base station transmits information associated with the above-mentioned feedback type information to an MSS via the “CQICH_Enhanced_Alloc_IE” field. 
     The following Table 29 exemplarily shows some parts of the “CQICH_Enhanced_Alloc_IE” field including the above-mentioned feedback type information. 
     
       
         
               
               
               
             
           
               
                 TABLE 29 
               
               
                   
               
             
             
               
                 CQICH_Enhanced_Alloc_IE( ){ 
                   
                   
               
               
                 ... 
                 ... 
                 ... 
               
               
                 Feedback type 
                 3 bits 
                 0b000 = Fast DL measurement/Antenna grouping 
               
               
                   
                   
                 for 6bit payload 
               
               
                   
                   
                 = MIMO mode/Antenna grouping for 4bit 
               
               
                   
                   
                 payload 
               
               
                   
                   
                 0b001 = Fast DL measurement/Antenna selection 
               
               
                   
                   
                 for 6bit payload 
               
               
                   
                   
                 = MIMO mode/Antenna selection for 4bit payload 
               
               
                   
                   
                 0b010 = Fast DL measurement/Reduced 
               
               
                   
                   
                 codebook for 6bit payload 
               
               
                   
                   
                 = MIMO mode/Reduced codebook for 4bit 
               
               
                   
                   
                 payload 
               
               
                   
                   
                 0b011 = Quantized precoding weight feedback 
               
               
                   
                   
                 0b100 = Index to precoding matrix in codebook 
               
               
                   
                   
                 0b101 = Channel Matrix Information 
               
               
                   
                   
                 0b110 = Per stream power control 
               
               
                   
                   
                 0b111 = reserved 
               
               
                 ... 
                 ... 
                 ... 
               
               
                   
               
             
          
         
       
     
     Although the use of the secondary fast feedback channel is requested by the BS to the MSS, the MSS has an option to request the usage by sending a request message to the BS. As apparent from the above description, a method for receiving a non-coherent detectable signal in a broadband wireless access system according to the present invention can transmit other signal(s) instead of a pilot signal when signal detection can be performed according to the non-coherent detection scheme, resulting in the implementation of increased transmission efficiency. 
     Although the present invention is described in the context of mobile communication, the present invention may also be used in any wireless communication systems using mobile devices, such as PDAs and laptop computers equipped with wireless communication capabilities. 
     The preferred embodiments may be implemented as a method, apparatus or article of manufacture using standard programming and/or engineering techniques to produce software, firmware, hardware, or any combination thereof. The term “article of manufacture” as used herein refers to code or logic implemented in hardware logic (e.g., an integrated circuit chip, Field Programmable Gate Array (FPGA), Application Specific Integrated Circuit (ASIC), etc.) or a computer readable medium (e.g., magnetic storage medium (e.g., hard disk drives, floppy disks, tape, etc.), optical storage (CD-ROMs, optical disks, etc.), volatile and non-volatile memory devices (e.g., EEPROMs, ROMs, PROMs, RAMs, DRAMs, SRAMs, firmware, programmable logic, etc.). 
     Code in the computer readable medium is accessed and executed by a processor. The code in which preferred embodiments are implemented may further be accessible through a transmission media or from a file server over a network. In such cases, the article of manufacture in which the code is implemented may comprise a transmission media, such as a network transmission line, wireless transmission media, signals propagating through space, radio waves, infrared signals, etc. Of course, those skilled in the art will recognize that many modifications may be made to this configuration without departing from the scope of the present invention, and that the article of manufacture may comprise any information bearing medium known in the art. 
       FIGS. 9A and 9B  illustrate a structure of a transmitter unit and receiver unit of a mobile communication device in accordance with one embodiment of the present invention. Referring to  FIG. 9A , a transmitter unit  500  preferably comprises a processor  510  for processing a signal to be transmitted. Before transmission, data bits are channel coded in a channel coder  520 , wherein redundancy bits are added to data bits. The data bits are then mapped to a signal such as QPSK or 16QAM in a symbol mapper  530 . Subsequently, the signal goes through subchannel modulation in a subchannel modulator  540  wherein the signal is mapped to the OFDMA subcarriers. Afterward, an OFDM waveformed-signal is constructed by combining several subcarriers through an Inverse Fast Fourier Transform (IFFT)  550 . Finally, the signal is filtered through filter  560 , converted to an analog signal by a digital-to-analog converter (DAC)  570  and transmitted to a receiver by an RF module  580 . 
     Referring to  FIG. 9B , a structure of a receiver  600  of the present invention is similar to that of the transmitter  500 ; however, the signal goes through a reverse process. Preferably, a signal is received by an RF module  680  and subsequently converted to a digital signal by an analog-to-digital converter  670  and filtered through filter  660 . Upon filtering, the signal goes through a Fast Fourier Transform (FFT)  650  for deconstructing the waveformed-signal. The signal is then subchannel demodulated in subchannel demodulator  640 , symbol demapped by symbol demapper  630  and channel decoded by channel decoder  620  prior to being forwarded to a processor  610  for processing. 
     Preferably, when a user enters instructional information, such as a phone number, for example, into the mobile communication device by pushing buttons of a keypad or by voice activation using a microphone, the processor  510  or  610  receives and processes the instructional information to perform the appropriate function, such as to dial the telephone number. Operational data may be retrieved from a storage unit to perform the function. Furthermore, the processor  510  or  610  may display the instructional and operational information on a display for the user&#39;s reference and convenience. 
     The processor issues instructional information to the RF module  580  or  680 , to initiate communication, for example, transmit radio signals comprising voice communication data. The RF module comprises a receiver and a transmitter to receive and transmit radio signals. An antenna facilitates the transmission and reception of radio signals. Upon receiving radio signals, the RF module may forward and convert the signals to baseband frequency for processing by the processor. The processed signals would be transformed into audible or readable information outputted via a speaker, for example. 
     The processor is adapted to store message history data of messages received from and messages transmitted to other users in the storage unit, receive a conditional request for message history data input by the user, process the conditional request to read message history data corresponding to the conditional request from the storage unit, and output the message history data to the display unit. The storage unit is adapted to store message history data of the received messages and the transmitted messages. 
       FIGS. 10A and 10B  respectively illustrate an uplink channel primary tile and an uplink channel secondary tile, where the x-axis represents a time domain and a y-axis represents a frequency domain. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.