Abstract:
A transmission method and apparatus that combines the benefits of DFT precoding and transmit diversity coding for PUCCH transmission. In one aspect, the invention provides an improved transmit diversity coding method and apparatus for DFTS-OFDM PUCCH with minimal impact on multiplexing capacity. In one embodiment, the improved transmit diversity method and apparatus has the feature of employing frequency-domain separation for the payload signals.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/373,531, filed on Aug. 13, 2010, which is incorporated by reference herein. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates to transmit diversity for discrete Fourier transform (DFT) precoded channels. 
       BACKGROUND 
       [0003]    Long-Term Evolution (LTE) uses orthogonal frequency-division multiplexing (OFDM) in the downlink and discrete Fourier transform (DFT) spread OFDM (DFTS-OFDM) in the uplink. DFTS-OFDM allows for flexible bandwidth assignment and orthogonal multiple access not only in the time domain, but also in the frequency domain. Thus, the LTE uplink scheme is also sometimes referred to as Single-Carrier FDMA (SC-FDMA). In the time domain, LTE downlink and uplink transmissions are organized into radio frames of 10 ms, each radio frame consisting of ten equally-sized subframes of length Tsubframe=1 ms. The resource allocation in LTE is typically described in Walls of resource blocks, where a resource block corresponds to one slot (0.5 ms) (i.e., there are two slots per subframe) in the time domain and 12 contiguous subcarriers in the frequency domain. 
         [0004]    To support the transmission of downlink and uplink transport channels, certain uplink layer 1 and layer 2 (L1/L2) control signaling is used. The uplink L1/L2 control signaling includes: (a) hybrid-automatic repeat request (HARQ) acknowledgements (ACK/NACK) for received downlink data; (b) channel-status reports related to downlink channel conditions, which reports may be used by the base station in scheduling the transmission of data in the downlink; and (c) scheduling requests indicating that the mobile terminal (a.k.a., “user equipment (UE)”) needs uplink resources for uplink data transmissions. For example, after receiving downlink data in a subframe from a base station, the UE attempts to decode the data and reports to the base station whether the decoding was successful (ACK) or not (NACK). In case of an unsuccessful decoding attempt, the base station can retransmit the erroneous data. 
         [0005]    A UE should transmit uplink L1/L2 control signaling regardless of whether or not the UE has any uplink transport-channel (UL-SCH) data to transmit and, thus, regardless of whether or not the UE has been assigned any uplink resources for UL-SCH data transmission. Hence, two different methods are used for the transmission of the uplink L1/L2 control signaling, depending on whether or not the UE has been assigned an uplink resource for UL-SCH data transmission. 
         [0006]    In case the UE does not have a valid scheduling grant—that is, no resources have been assigned for UL-SCH in the current subframe—a separate physical channel, the Physical Uplink Control Channel (PUCCH), is used for transmission of uplink L1/L2 control signaling. Otherwise, the uplink L1/L2 control signaling is multiplexed with the coded UL-SCH onto the Physical Uplink Shared Channel (PUSCH). 
         [0007]    More specifically, if the UE has not been assigned an uplink resource for data transmission, the L1/L2 control information (e.g., channel-status reports, HARQ acknowledgments, and scheduling requests) is transmitted in uplink resources (resource blocks) specifically assigned for the uplink L1/L2 control information on the PUCCH. These resources are located at the edges of the total available cell bandwidth. Each such resource consists of 12 “subcarriers” (one resource block) within each of the two slots of an uplink subframe. 
         [0008]    LTE release-8 (Rel-8) has recently been standardized. LTE Rel-8 supports bandwidths up to 20 MHz. The Third Generation Partnership Project (3GPP) has initiated work on LTE release-10 (Rel-10). One of the parts of LTE Re1-10 is to support bandwidths larger than 20 MHz. One important requirement on LTE Rel-10 is to assure backward compatibility with LTE Rel-8. This should also include spectrum compatibility. That would imply that an LTE Rel-10 carrier, wider than 20 MHz, should appear as a number of LTE carriers to an LTE Re1-8 terminal. Each such carrier can be referred to as a Component Carrier (CC). In particular, for early LTE Rel-10 deployments, it can be expected that there will be a smaller number of LTE Rel-10-capable terminals compared to many LTE legacy terminals. Therefore, it is necessary to assure an efficient use of a wide carrier also for legacy terminals, i.e. that it is possible to implement carriers where legacy terminals can be scheduled in all parts of the wideband LTE Re1-10 carrier. The straightforward way to obtain this would be by means of Carrier Aggregation (CA). CA implies that an LTE Rel-10 terminal can receive multiple CCs, where the CCs have, or, at the least, have the possibility to have, the same structure as a Re1-8 carrier. 
         [0009]    The CA PUCCH is based on DFTS-OFDM for a UE supporting more than 4 ACK/NACK bits. The multiple ACK/NACK bits (may also include scheduling request (SR) bits) are encoded to form 48 coded bits. The 48 coded bits are then scrambled with cell-specific (and possibly DFTS-OFDM symbol dependent) sequences. The first 24 bits are transmitted within the one slot and the other 24 bits are transmitted within a second slot. The 24 bits per slot are converted into 12 QPSK symbols, spread across five DFTS-OFDM symbols, DFT precoded and transmitted within one resource block (bandwidth) and five DFTS-OFDM symbols (time). The spreading sequence is UE specific and enables multiplexing of up to five users within the same resource block. A demodulation reference signal is also transmitted in each slot. The reference signal comprises a reference sequence. As used herein, a “reference sequence” may represent any information transmitted by a transmitting device to permit or otherwise facilitate the demodulation, by a receiving device, of data associated with the reference sequence (e.g., data transmitted with the reference sequence). For example, in particular embodiments, the reference sequence may represent a cyclic shifted CAZAC sequence (e.g., the computer optimized sequences in 3GPP TS 36.211). To improve orthogonality among reference signals even further, an orthogonal cover code of length two can be applied to the reference signals. 
         [0010]    In the continuing evolution of the LTE system, additional transmit antennas are introduced to the UE to improve transmission performance. There is, hence, a need to design transmission methods and apparatuses that combine the benefits of DFT precoding and transmit diversity coding for PUCCH transmission (including CA PUCCH transmission). 
       SUMMARY 
       [0011]    In one aspect, particular embodiments of the disclosed solution provide a transmission method and apparatus that combines the benefits of DFT precoding and transmit diversity coding for PUCCH transmission. For example, particular embodiments provide an improved transmit diversity coding method and apparatus for DFTS-OFDM PUCCH with minimal impact on multiplexing capacity. In certain embodiments, the improved transmit diversity method and apparatus has the feature of employing frequency-domain separation for the payload signals as well as the time-domain orthogonal spreading separation and/or sequence phase shift separation. 
         [0012]    In one embodiment, a transmit diversity coding method for DFT precoded channels (e.g., DFTS-OFDM PUCCH) includes producing a block of data symbols and transforming the block of data symbols to produce a first block of transformed symbols and a second block of transformed symbols. A first antenna of a mobile terminal is used to transmit, during a slot of a subframe of a radio frame and using only a first set of subcarriers, the first block of transformed symbols. The first antenna is also used to transmit a first reference sequence during the same slot. A second antenna of the mobile terminal is used to transmit, during the same slot and using only a second set of subcarriers, the second block of transformed symbols. The second antenna is also used to transmit a second reference sequence during the same slot. To enhance signal diversity, the first set of subcarriers is orthogonal with the second set of subcarriers. Additionally, the first reference sequence and the second reference sequence may be transmitted using a third set of subcarriers that comprises that first set of subcarriers and the second set of subcarriers. 
         [0013]    In some embodiments, the method also includes producing a second block of data symbols and transforming the second block of data symbols to produce a third block of transformed symbols and a fourth block of transformed symbols. In these embodiments, the method also includes (i) using the first antenna to transmit, during a second slot of the subframe, the third block of transformed symbols and the first reference sequence, and (ii) using the second antenna to transmit, during the second slot, the fourth block of transformed symbols and the second reference sequence. The third block of transformed symbols may be transmitted using a fourth set of subcarriers and the fourth block of transformed symbols may be transmitted using a fifth set of subcarriers that is orthogonal with the fourth set of subcarriers. In some embodiments, the first and fifth sets of subcarriers consist only of even indexed subcarriers and the second and fourth sets of subcarriers consist only of odd indexed subcarriers. In other embodiments, the first and fifth sets of subcarriers consist only of odd indexed subcarriers and the second and fourth sets of subcarriers consist only of even indexed subcarriers. 
         [0014]    In some embodiments, the first reference sequence may be orthogonal to the second reference sequence. For instance, the first reference sequence may be a cyclic shift of the second reference sequence. 
         [0015]    In some embodiments, the step of transforming the block of data symbols includes the following steps: dividing the block of data symbols into at least a first sub-block and a second sub-block; applying a discrete Fourier transform (DFT) to the first sub-block to produce the first block of transformed symbols; and applying a discrete Fourier transform (DFT) to the second sub-block to produce the second block of transformed symbols. 
         [0016]    In a particular embodiment, the block of data symbols consists of twelve data symbols. In this particular embodiment, the step of transforming the block of twelve data symbols may include: dividing the block of twelve symbols into first sub-block of six symbols and a second sub-block of six symbols; applying a DFT of size six to the first sub-block of six symbols to produce the first block of transformed symbols; and applying a DFT of size six to the second sub-block of six symbols to produce the second block of transformed symbols. 
         [0017]    In some embodiments, the step of transmitting the first block of transformed symbols includes mapping each symbol within the first block of transformed symbols to a particular subcarrier within the first set of subcarriers and applying an inverse fast Fourier transform (IFFT) to the first block of transformed symbols. Similarly, the step of transmitting the second block of transformed symbols may include mapping each symbol within the second block of transformed symbols to a particular subcarrier within the second set of subcarriers and applying the IFFT to the second block of transformed symbols. 
         [0018]    In one embodiment, a transmit diversity apparatus for discrete Fourier transform (DFT) precoded channels includes a first antenna, a second antenna, and a data processor coupled to the first antenna and the second antenna. The data processor is configured to: (a) produce a block of data symbols from a set of message bits, (b) transform the block of data symbols to produce a first block of transformed symbols and a second block of transformed symbols; (c) use the first antenna to transmit, during a slot of a subframe of a radio frame, the first block of transformed symbols and a first reference sequence; and (d) use the second antenna to transmit, during the slot, the second block of transformed symbols and a second reference sequence. The data processor may further be configured such that (i) the first block of transformed symbols is transmitted using a first set of subcarriers, (ii) the second block of transformed symbols is transmitted using a second set of subcarriers that is orthogonal with the first set of subcarriers, and (iii) the first reference sequence and the second reference sequence are transmitted using a third set of subcarriers that comprises that first set of subcarriers and the second set of subcarriers. 
         [0019]    In another aspect, particular embodiments of the disclosed solution provide a mobile terminal comprising any one of the herein described transmit diversity apparatuses for discrete Fourier transform (DFT) precoded channels. 
         [0020]    The above and other aspects and embodiments are described below with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers indicate identical or functionally similar elements. 
           [0022]      FIG. 1  illustrates a particular embodiment of a wireless communication system that supports transmit diversity coding for PUCCH transmissions. 
           [0023]      FIG. 2  is a flow chart illustrating a process for transmit diversity coding of DFTS-OFDM PUCCH. 
           [0024]    FIGS.  3 A, 3 B, 4 A, and  4 B illustrate various subcarrier mappings according to particular embodiments. 
           [0025]      FIG. 5  illustrates data summarizing the performance of a transmit diversity method according to particular embodiments. 
           [0026]      FIG. 6  is a flow chart illustrating example processes for implementing certain steps shown in  FIG. 2 . 
           [0027]      FIG. 7  is a block diagram of a particular embodiment of an apparatus for transmit diversity coding of DFTS-OFDM PUCCH. 
           [0028]      FIG. 8  is a block diagram of a DFT module that may be utilized in particular embodiments of the apparatus shown in  FIG. 7 . 
           [0029]      FIG. 9  is a block diagram of an alternative embodiment of the apparatus shown in  FIG. 7 . 
           [0030]      FIG. 10  is a block diagram of a mobile terminal. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Referring now to  FIG. 1 ,  FIG. 1  illustrates a mobile terminal  102  having multiple antennas (e.g., antenna  111  and antenna  112 ) and communicating wirelessly with a network  110 . Particular embodiments of mobile terminal  102  provide an improved transmit diversity coding process for DFTS-OFDM PUCCH. 
         [0032]    Referring now to  FIG. 2 ,  FIG. 2  is a flow chart illustrating an example of such a process  200  that may be implemented by particular embodiments of mobile  102 . Process  200  assumes that mobile terminal  102  includes only two antennas: antenna  111  and antenna  112 , but the described solution is not limited to two antennas as more than two antennas can be used. Process  200  may begin in step  202  where a media-access control (MAC) layer of mobile terminal  102  generates message bits (e.g., control information such as ACK/NACK bits, ACK/NACK bits plus a scheduling request bit, etc.). In step  204 , the message bits are encoded into a block of B bits (e.g., the message bits may be coded to form a block of 48 coded bits). In step  206 , the block of coded bits is scrambled. In some embodiments, a block of coded bits may be scrambled using a cell-specific (and possible DFTS-OFDM symbol dependent) sequence to produce a block of B (e.g., B=48) scrambled bits {tilde over (b)}(0),{tilde over (b)}(1), . . . , {tilde over (b)}(B−1), according to {tilde over (b)}(i)=(b(i)+c(i))mod2, where i=0,1, . . . , B−1 and the scrambling sequence c(i) is given by section 7.2 of 3GPP TS 36.211. The scrambling sequence generator can for example be initialized with c init =└n s /2┘·2 9 +N ID   cell  at the start of each subframe. 
         [0033]    In step  208 , a set of data symbols is produced from the block of scrambled bits. For example, in step  208 , a first sub-set of the block of scrambled bits (e.g., 24 of the 48 bits) is used to produce a first block of N data symbols (e.g., 12 data symbols) and a second sub-set of the block of scrambled bits (e.g., the other 24 of the 48 bits) is used to produce a second block of N data symbols. In one embodiment, in step  208  the block of scrambled bits may be QPSK modulated to produce two blocks of complex-valued modulation symbols: d(0), . . . , d(N−1) and d(N), . . . , d(2N−1). 
         [0034]    In step  210 , the set of data symbols is divided into two blocks: a first block of data symbols (e.g., d(0), . . . , d(N−1)) and a second block of data symbols (e.g., d(N), . . . , d(2N−1)). The first block will be transmitted during the first slot of a subframe and the second bock will be transmitted during the second slot of the subframe. 
         [0035]    In step  212 , the first block of data symbols is transformed to produce DFT-precoded data (e.g., in some embodiments, prior to transforming the block of data symbols, each data symbol is multiplied by a value (w(i))). In particular embodiments, the first block of data symbols is transformed to produce a first block of transformed data symbols and a second block of transformed data symbols. 
         [0036]    In step  214 , an antenna  111  of mobile terminal  102  and a first set of subcarriers are used, during the first slot of the subframe, to transmit the first block of transformed data symbols. In step  215 , antenna  111  is used, during the first slot of the subframe, to transmit a first reference sequence. In step  216 , antenna  112  of mobile terminal  102  and a second set of subcarriers are used, during the first slot of the subframe, to transmit the second block of transformed data symbols. In step  217 , antenna  112  is used, during the first slot of the subframe, to transmit a second reference sequence. 
         [0037]    Advantageously, the first set of subcarriers is orthogonal with the second set of subcarriers. This is illustrated in  FIG. 3A . As show in  FIG. 3A , the even indexed subcarriers (i.e., f0, f2, . . . , f10) are used to transmit the first block of transformed data symbols, but the odd indexed subcarrier are set to zero, and the odd indexed subcarriers (i.e., f1, f3, . . . , f11) are used to transmit the second block of transformed data symbols, but the even indexed subcarrier are set to zero (in the example, antenna port 0 corresponds to antenna  111  and antenna port 1 corresponds to antenna  112 ). 
         [0038]    This provides the feature of frequency-domain separation for the payload signals (i.e., the first and second blocks of transformed data symbols) and time-domain orthogonal spreading separation and/or sequence phase shift separation. In steps  215  and  217 , the reference sequences may be transmitted using all of the twelve available subcarriers. In this case, the first reference sequence should be orthogonal with the second reference sequence. In an alternative embodiment, the reference sequences need not be orthogonal. In such embodiments, it would be advantageous to transmit the first reference sequences using a set of subcarriers and transmit the second reference sequences using a set of subcarriers that are orthogonal to the subcarriers used to transmit the first reference sequence. 
         [0039]    In step  218 , the second block of data symbols is transformed to produce DFT-precoded data. For example, the second block of data symbols is transformed to produce a third block of transformed data symbols and a fourth block of transformed data symbols. In step  220 , antenna  111  and a third set of subcarriers are used, during the second slot of the subframe, to transmit the third block of transformed data symbols. In step  221 , antenna  111  is used, during the second slot of the subframe, to transmit the first reference sequence. In step  222 , antenna  112  and a fourth set of subcarriers are used, during the second slot of the subframe, to transmit the fourth block of transformed data symbols. In step  223 , antenna  112  is used, during the second slot of the subframe, to transmit the second reference sequence. 
         [0040]    Advantageously, the third set of subcarriers is orthogonal with the fourth set of subcarriers. This is illustrated in  FIG. 3B . As show in  FIG. 3B , the even indexed subcarriers (i.e., f0, f2, . . . , f10) are used to transmit the third block of transformed data symbols, but the odd indexed subcarrier are set to zero, and the odd indexed subcarriers (i.e., f1, f3, . . . , f11) are used to transmit the fourth block of transformed data symbols, but the even indexed subcarrier are set to zero. This provides the feature of frequency-domain separation for the payload signals (i.e., the third and fourth blocks of transformed data symbols) and time-domain orthogonal spreading separation and/or sequence phase shift separation. In steps  221  and  223 , the reference sequences may be transmitted using all of the twelve available subcarriers. In this case, the first reference sequence should be orthogonal with the second reference sequence. 
         [0041]    In another embodiment, to provide even more uniform spatial diversity exposure to all the signals, cyclic frequency offset can be introduced for different symbols as illustrated in FIGS.  4 A,B. As shown in these figures, only even indexed subcarriers (i.e., f0, f2, . . . , f10) are used to transmit the first and fourth blocks of transformed data symbols, which data is transmitted via antenna ports 0 and 1, respectively, and only the odd indexed subcarriers (i.e., f1, f3, . . . , f11) are used to transmit the second and third blocks of transformed data symbols, which data is transmitted via antenna ports 0 and 1, respectively. 
         [0042]    The above described transmit diversity scheme for the DFTS-OFDM PUCCH provides substantial link performance gains. The required operating SNR for these different schemes are detemiined based on the following performance requirements: 
         [0000]    
       
         
           
             
               
                 
                   Freq 
                    
                   
                     ( 
                     
                       
                         PUCCH 
                          
                         
                             
                         
                          
                         DTX 
                       
                       -&gt; 
                       
                         ACK 
                          
                         
                             
                         
                          
                         bits 
                       
                     
                     ) 
                   
                 
                 = 
                 
                   
                     
                       # 
                        
                       
                         ( 
                         
                           false 
                            
                           
                               
                           
                            
                           ACK 
                            
                           
                               
                           
                            
                           bits 
                         
                         ) 
                       
                     
                     
                       # 
                        
                       
                         ( 
                         
                           PUCCH 
                            
                           
                               
                           
                            
                           DTX 
                         
                         ) 
                       
                     
                   
                   ≤ 
                   
                     10 
                     
                       - 
                       2 
                     
                   
                 
               
                
               
                 
 
               
                
               
                 Pr 
                  
                 
                   ( 
                   
                     
                       NAK 
                        
                       
                           
                       
                        
                       or 
                        
                       
                           
                       
                        
                       DTX 
                        
                       
                           
                       
                        
                       bits 
                     
                     -&gt; 
                     
                       ACK 
                        
                       
                           
                       
                        
                       bits 
                     
                   
                   ) 
                 
               
             
             ≤ 
             
               10 
               
                 - 
                 3 
               
             
           
         
       
       
         
           
             
               Pr 
                
               
                 ( 
                 
                   
                     ACK 
                      
                     
                         
                     
                      
                     bits 
                   
                   -&gt; 
                   
                     NAK 
                      
                     
                         
                     
                      
                     bits 
                      
                     
                         
                     
                      
                     or 
                      
                     
                         
                     
                      
                     DTX 
                   
                 
                 ) 
               
             
             ≤ 
             
               10 
               
                 - 
                 2 
               
             
           
         
       
     
         [0043]    The link simulations are set such that Freq(PUCCH DTX→ACK bits)=10 □2 . The operating SNRs is taken as the larger of those required for achieving Pr(ACK bits→NAK bits or DTX)=10 □2  and Pr(NAK or DTX bits→ACK bits)=10 □3 . The performance of the transmit diversity scheme is summarized in  FIG. 5 . It can be observed that, with two antenna ports, link performance gains of around 2-2.5 dB can be obtained. Transmit diversity with three or four antenna ports can offer further link performance gains. 
         [0044]    Referring now to  FIG. 6 ,  FIG. 6  illustrates (a) exemplary steps  602 - 606  that may be performed in implementing step  212  of process  200  and (b) exemplary steps  608 - 610  that may be performed in implementing step  214  of process  200 . In step  602 , the first block of M data symbols is divided into two equal sized sub-blocks: a first sub-block of M/2 data symbols and a second sub-block M/2 data symbols. In step  604 , a DFT of size M/2 is applied to the first sub-block of data symbols to produce the first block of transformed data symbols. Similarly, in step  606 , a DFT of size M/2 is applied to the second sub-block of data symbols to produce the second block of transfotined data symbols. In step  608 , each data symbol within the first block of transformed data symbols is mapped to a particular subcarrier within the first set of subcarriers. In step  610 , an inverse fast Fourier transfotin (IFFT) is applied to the first block of transformed data symbols. 
         [0045]    Referring now to  FIG. 7 ,  FIG. 7  illustrates a transmit diversity coding apparatus  700  for DFTS-OFDM PUCCH, according to an embodiment. 
         [0046]    As shown in  FIG. 7 , apparatus  700  may receive message bits (denoted o 0 , o 1 , o 2 , o 3 , . . . , o o-1 ) from a media-access control (MAC) layer (e.g., HARQ ACK/NACK bits) and employ an encoder  702  for coding the message bits into a block of bits b(0),b(1), . . . , b(B−1) according to Section 5.2.2.6.4 of 3GPP TS 36.212, where B=4N sc   RB  (e.g., the bits may be coded to faun a block of 48 coded bits). 
         [0047]    In one embodiment, these message bits may consist of HARQ ACK/NACK bits. In another embodiment, the message bits may consist of HARQ ACK/NACK bits (e.g., bit o 0 , o 1 , o 2 , o 3 , . . . , o o-2 ) and a scheduling request bit (e.g., bit o o-1 ). The scheduling request bit shall be set to 1 to request scheduling and 0 otherwise. In yet another embodiment the bits corresponding to HARQ feedback may have been obtained by a logical AND operation of several individual HARQ feedback bits. This embodiment corresponds to partial bundling where multiple HARQ feedback bits are logical AND combined and only one bit is transmitted per bundle. 
         [0048]    Apparatus  700  includes a scrambler  704  for scrambling the block of coded bits b(0),b(1), . . . , b(B−1). The scrambler may use a cell-specific (and possible DFTS-OFDM symbol dependent) sequence to produce a block of B scrambled bits {tilde over (b)}(0),{tilde over (b)}(1), . . . ,{tilde over (b)}(B−1), according to {tilde over (b)}(i)=(b(i)+c(i))mod2, where i=0,1, . . . , B−1 and the scrambling sequence c(i) is given by section 7.2 of 3GPP TS 36.211. The scrambling sequence generator can for example be initialized with c init =└n s /2┘·2 9 +N ID   cell  at the start of each subframe. 
         [0049]    In one embodiment illustrated in  FIG. 7 , the output from encoder  702  may be divided into two sub-blocks: a first sub-block {tilde over (b)}(0),{tilde over (b)}(1), . . . , {tilde over (b)}(B/2−1) and a second sub-block {tilde over (b)}(B/2), {tilde over (b)}(B/2+1), . . . , {tilde over (b)}(B−1). The first sub-block is repeated N SF,0   PUCCh  times and the second sub-block is repeated N SF,1   PUCCH  times. The repeated coded bit sequence is then scrambled by the scrambling code sequence with initialization method disclosed above. 
         [0050]    Apparatus  700  also includes a symbol generator  706  that receives the coded and scrambled bits, uses a first set of those bits (e.g., 24 of the 48 bits) to produce a first block of N data symbols  791  (e.g., 12 data symbols) and uses the other bits (e.g., the other 24 of the 48 bits) to produce a second block of N data symbols  792 . For example, symbol generator  706  may be a modulator that QPSK modulates the bits to produce a block of complex-valued data symbols: d(0), . . . , d(2N sc   RB −1), which may be divided into two blocks of complex-valued modulation symbols: a first block d(0), . . . , d(NR sc   RB −1) and a second block d(N sc   RB ), . . . , d(2NR sc −1). 
         [0051]    As shown in  FIG. 7 , for each of the first and second blocks of data symbols, the block of data symbols is spread with an orthogonal sequence w n     oc   (i), thereby producing, in total, a block of complex-valued data symbols y(0), . . . , y(M symb −1) according to: 
         [0000]        y ( l·N   sc   RB   +i )= w   n     oc   ( l  mod  N   SF,0   PUCCH )· d (└ l/N   SF,0   PUCCH   ┘·N   sc   RB   +i )
 
         [0000]        i= 0, . . . ,  N   sc   RB −1
 
         [0000]        l= 0, . . . ,  M   symb   /N   sc   RB −1
 
         [0000]    where 
         [0000]        M   symb =( N   SF,0   PUCCH   +N   SF,1   PUCCH )· N   sc   RB .
 
         [0000]    For normal DFT-S-OFDM PUCCH N SF,0   PUCCH =5 and N SF,1   PUCCH =5. For shortened DFT-S-OFDM PUCCH N SF,0   PUCCH =5 and N SF,1   PUCCH =4. 
         [0052]    The sequence w n     oc   (i) is given in tables I and II below. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE I 
               
             
             
               
                   
               
               
                 Orthogonal sequences [w(0) . . . 
               
               
                 w(N SF   PUCCH  − 1)] for N SF   PUCCH  = 5. 
               
             
          
           
               
                   
                   
                 Orthogonal sequences 
               
               
                   
                 Sequence index n oc (n s ) 
                 [w(0) . . . w(N SF   PUCCH  − 1)] 
               
               
                   
                   
               
               
                   
                 0 
                 [1 1 1 1 1] 
               
               
                   
                 1 
                 [1 e j2π/5  e j4π/5  e j6π/5  e j8π/5 ] 
               
               
                   
                 2 
                 [1 e j4π/5  e j8π/5  e j2π/5  e j6π/5 ] 
               
               
                   
                 3 
                 [1 e j6π/5  e j2π/5  e j8π/5  e j4π/5 ] 
               
               
                   
                 4 
                 [1 e j8π/5  e j6π/5  e j4π/5  e j2π/5 ] 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE II 
               
             
             
               
                   
               
               
                 Orthogonal sequences [w(0) . . . 
               
               
                 w(N SF   PUCCH  − 1)] for N SF   PUCCH  = 4. 
               
             
          
           
               
                   
                   
                 Orthogonal sequences 
               
               
                   
                 Sequence index n oc (n s ) 
                 [w(0) . . . w(N SF   PUCCH  − 1)] 
               
               
                   
                   
               
               
                   
                 0 
                 [+1 +1 +1 +1] 
               
               
                   
                 1 
                 [+1 −1 +1 −1] 
               
               
                   
                 2 
                 [+1 −1 −1 +1] 
               
               
                   
                 3 
                 [+1 +1 −1 −1] 
               
               
                   
                   
               
             
          
         
       
     
         [0053]    The block of complex-valued data symbols y(0), . . . y(M symb −1) is divided into M symb /M sc   PUCCH  blocks where M sc   PUCH =N sc   RB . In the example shown, the number of blocks is equal to 10 and each block corresponds to one SC-FDMA symbol. For example, the first block consists of y(0), . . . ,y(N sc   RB −1), the second block consists of y(N sc   RB ), . . . ,y(2N sc   RB −1), and the tenth block consists of y(9N sc   RB ), . . . ,y(10N sc   RB −1). 
         [0054]    In the embodiment shown, five of the ten blocks of data symbols are processed by a set of DFTs  708  and a set IFFTs  710 , which set of IFFTs consists of a first subset of IFFTs  711  and a second subset of IFFTs  712 . The other five blocks of data symbols are processed by a set of DFTs  718  and a set of IFFTs  720 , which set of IFFTs consists of a first subset of IFFTs  721  and a second subset of IFFTs  722 . The data processed by DFTs  708  and IFFTs  710  is transmitted in the first slot of a subframe and the data processed DFTs  718  and IFFTs  720  is transmitted in the second slot of the subframe. 
         [0055]    Each DFT in sets  708  and  718  transform precodes one of the above described sets of data symbols. For example, DFT  708   a  will transform precode the block of data symbols y(0), . . . ,y(N sc   RB −1). In some embodiment, the transform precoding applied by the DFTs is applied according to: 
         [0000]    
       
         
           
             
               
                 z 
                 
                   ( 
                   p 
                   ) 
                 
               
                
               
                 ( 
                 
                   
                     l 
                     · 
                     
                       M 
                       sc 
                       PUCCH 
                     
                   
                   + 
                   
                     k 
                     · 
                     P 
                   
                   + 
                   
                     p 
                     ′ 
                   
                 
                 ) 
               
             
             = 
             
               { 
               
                 
                   
                     
                       
                         
                           
                             
                               
                                 
                                   
                                     1 
                                     
                                       
                                         
                                           M 
                                           sc 
                                           PUCCH 
                                         
                                         / 
                                         P 
                                       
                                     
                                   
                                    
                                   
                                     ∑ 
                                     
                                       i 
                                       = 
                                       0 
                                     
                                     
                                       
                                         
                                           M 
                                           sc 
                                           PUCCH 
                                         
                                         / 
                                         P 
                                       
                                       - 
                                       1 
                                     
                                   
                                 
                               
                             
                             
                               
                                 
                                   
                                     y 
                                      
                                     
                                       
                                         ( 
                                         
                                           
                                             l 
                                             · 
                                             
                                               M 
                                               sc 
                                               PUCCH 
                                             
                                           
                                           + 
                                           
                                             i 
                                             · 
                                             P 
                                           
                                           + 
                                           p 
                                         
                                         ) 
                                       
                                       · 
                                       
                                          
                                         
                                           j 
                                            
                                           
                                             
                                               2 
                                                
                                               π 
                                                
                                               
                                                   
                                               
                                                
                                               k 
                                             
                                             
                                               
                                                 M 
                                                 sc 
                                                 PUCCH 
                                               
                                               / 
                                               P 
                                             
                                           
                                         
                                       
                                     
                                   
                                   , 
                                 
                               
                             
                           
                         
                         
                           
                             
                               if 
                                
                               
                                   
                               
                                
                               
                                 p 
                                 ′ 
                               
                             
                             = 
                             p 
                           
                         
                       
                       
                         
                           
                             0 
                             , 
                           
                         
                         
                           
                             
                               if 
                                
                               
                                   
                               
                                
                               
                                 p 
                                 ′ 
                               
                             
                             ≠ 
                             p 
                           
                         
                       
                     
                      
                     
                       
 
                     
                      
                     
                         
                     
                      
                     p 
                   
                   = 
                   0 
                 
                 , 
                 … 
                  
                 
                     
                 
                 , 
                 
                   
                     P 
                     - 
                     
                       1 
                        
                       
                         
 
                       
                        
                       
                           
                       
                        
                       
                         p 
                         ′ 
                       
                     
                   
                   = 
                   0 
                 
                 , 
                 … 
                  
                 
                     
                 
                 , 
                 
                   
                     P 
                     - 
                     
                       1 
                        
                       
                         
 
                       
                        
                       
                           
                       
                        
                       k 
                     
                   
                   = 
                   0 
                 
                 , 
                 … 
                  
                 
                     
                 
                 , 
                 
                   
                     
                       
                         M 
                         sc 
                         PUCCH 
                       
                       / 
                       P 
                     
                     - 
                     
                       1 
                        
                       
                         
 
                       
                        
                       
                           
                       
                        
                       l 
                     
                   
                   = 
                   0 
                 
                 , 
                 … 
                  
                 
                     
                 
                 , 
                 
                   
                     
                       M 
                       symb 
                     
                     / 
                     
                       M 
                       sc 
                       PUCCH 
                     
                   
                   - 
                   1 
                 
               
             
           
         
       
     
         [0000]    resulting in P blocks of complex-value symbols z (p) (0), . . . ,z (p) (M symb −1), where p=0, . . . , P−1 and P is equal to the number of transmit antennas (in the embodiment shown P=2, but P may be greater than 2). The p-th block of complex-value symbols z (p) (0), . . . ,z (p) (M symb −1) is transmitted on antenna port p. In our example, antenna port 0 corresponds to antenna  111  and antenna port 1 corresponds to antenna  112 . It can be seen from the above computation that the p-th block may have nonzero values at in indices [p, p+P, p+2P, . . . ] and zeros at all other indices. This is illustrated for the case of P=2 in  FIGS. 3A and 3B . 
         [0056]    As an example, DFT  708   a  will produce two blocks of transformed data symbols: a first block of transformed symbols) z (0) (0), . . . , z (0) (N sc   RB −1) and a second block of transformed symbols z (1) (0), . . . ,z (1) (N sc   RB −1). As described above, the first block of transformed symbols) z (0) (0), . . . ,z (0) (N sc   RB −1) has nonzero values at in indices [0, 2, 4, . . . ] and zeros at all other indices, whereas the second block of transformed symbols z (1) (0), . . . ,z (1) (N sc   RB −1) has nonzero values at in indices [1, 3, 5, . . . ] and zeros at all other indices. 
         [0057]    Referring now to  FIG. 8 ,  FIG. 8  illustrates an example implementation of DFT  708   a . As shown, DFT  708   a  includes two 6 point DFTs: DFT  802  and DFT  804 . As further shown, the input to DFT  802  is y(0), y(2), y(4), y(6), y(8), y(10). DFT  802  transforms this input in the conventional manner to produce a first block of six transformed symbols z(0), z(2), z(4), z(6), z(8), z(10). This first block of six transformed symbols, together with six Os for padding, are provided to twelve consecutive inputs of an IFFT  711   a , as shown. Likewise the input to DFT  804  is y(1), y(3), y(5), y(7), y(9), y(11). DFT  804  transfomis this input in the conventional manner to produce a second block of six transformed symbols z(1), z(3), z(5), z(7), z(9), z(11). This second block of six transformed symbols together with six Os for padding are provided to twelve consecutive inputs of an IFFT  712   a  as shown. 
         [0058]    The output of IFFT  711   a  is coupled, via conventional transmission components, to antenna port 0 and the output of IFFT  712   a  is coupled, via conventional transmission components, to antenna port 1 so that the first and second blocks of transformed symbols are transmitted via antennas  111  and  112 , respectively, during the first slot of the subframe. As described above a first set of subcarriers will be used to transmit the first block of transformed symbols and a second set of subcarriers will be used to transmit the second block of transformed symbols, where the first set of subcarriers is orthogonal with the second set of subcarriers (see e.g.,  FIG. 3A ). 
         [0059]    In another embodiment, to enable per-SC-FDMA-symbol cyclic frequency offset, the transform precoding procedure described above may be modified such that the transform precoding applied by the DFTs is applied according to: 
         [0000]    
       
         
           
             
               
                 z 
                 
                   ( 
                   p 
                   ) 
                 
               
                
               
                 ( 
                 
                   
                     l 
                     · 
                     
                       M 
                       sc 
                       PUCCH 
                     
                   
                   + 
                   
                     ( 
                     
                       
                         k 
                         · 
                         P 
                       
                       + 
                       
                         p 
                         ′ 
                       
                       + 
                       
                         l 
                          
                         
                             
                         
                          
                         mod 
                          
                         
                             
                         
                          
                         
                           M 
                           sc 
                           PUCCH 
                         
                       
                     
                     ) 
                   
                 
                 ) 
               
             
             = 
             
               { 
               
                 
                   
                     
                       
                         
                           
                             
                               1 
                               
                                 
                                   
                                     M 
                                     sc 
                                     PUCCH 
                                   
                                   / 
                                   P 
                                 
                               
                             
                              
                             
                               ∑ 
                               
                                 i 
                                 = 
                                 0 
                               
                               
                                 
                                   
                                     M 
                                     sc 
                                     PUCCH 
                                   
                                   / 
                                   P 
                                 
                                 - 
                                 1 
                               
                             
                           
                         
                       
                       
                         
                           
                             
                               y 
                                
                               
                                 
                                   ( 
                                   
                                     
                                       l 
                                       · 
                                       
                                         M 
                                         sc 
                                         PUCCH 
                                       
                                     
                                     + 
                                     
                                       i 
                                       · 
                                       P 
                                     
                                     + 
                                     p 
                                   
                                   ) 
                                 
                                 · 
                                 
                                    
                                   
                                     
                                       - 
                                       j 
                                     
                                      
                                     
                                       
                                         2 
                                          
                                         π 
                                          
                                         
                                             
                                         
                                          
                                         k 
                                       
                                       
                                         
                                           M 
                                           sc 
                                           PUCCH 
                                         
                                         / 
                                         P 
                                       
                                     
                                   
                                 
                               
                             
                             , 
                           
                         
                       
                     
                   
                   
                     
                       
                         if 
                          
                         
                             
                         
                          
                         
                           p 
                           ′ 
                         
                       
                       = 
                       p 
                     
                   
                 
                 
                   
                     
                       0 
                       , 
                     
                   
                   
                     
                       
                         if 
                          
                         
                             
                         
                          
                         
                           p 
                           ′ 
                         
                       
                       ≠ 
                       p 
                     
                   
                 
               
             
           
         
       
     
         [0000]    where 
         [0000]        p= 0, . . . ,  P− 1 
         [0000]        p′= 0, . . . ,  P− 1 
         [0000]        k= 0, . . . ,  M   sc   PUCCH   /P− 1 
         [0000]        l= 0, . . . ,  M   symb   /M   sc   PUCCH− 1 
         [0060]    As with the other described transform precoding procedure, this procedure results in P blocks of complex-valued symbols z (p) (0 0 , . . . , z (p) (M symb −1), where p=0, . . . , P−1. The p-th block of complex-valued symbols z (p) (0), . . . , z (p) (M symb −1) is to be transmitted on antenna port p. An illustration of the per-SC-FDMA-symbol cyclic frequency offset for the case of P=2 is given in FIGS.  4 A,B. The cyclic frequency offset step Δ f  can also be larger than 1. In general, the extended transform precoding is given by 
         [0000]    
       
         
           
             
               
                 z 
                 
                   ( 
                   p 
                   ) 
                 
               
                
               
                 ( 
                 
                   
                     l 
                     · 
                     
                       M 
                       sc 
                       PUCCH 
                     
                   
                   + 
                   
                     ( 
                     
                       
                         k 
                         · 
                         P 
                       
                       + 
                       
                         p 
                         ′ 
                       
                       + 
                       
                         
                           l 
                            
                           
                               
                           
                           · 
                           
                             Δ 
                             f 
                           
                         
                          
                         mod 
                          
                         
                             
                         
                          
                         
                           M 
                           sc 
                           PUCCH 
                         
                       
                     
                     ) 
                   
                 
                 ) 
               
             
             = 
             
               { 
               
                 
                   
                     
                       
                         
                           
                             
                               1 
                               
                                 
                                   
                                     M 
                                     sc 
                                     PUCCH 
                                   
                                   / 
                                   P 
                                 
                               
                             
                              
                             
                               ∑ 
                               
                                 i 
                                 = 
                                 0 
                               
                               
                                 
                                   
                                     M 
                                     sc 
                                     PUCCH 
                                   
                                   / 
                                   P 
                                 
                                 - 
                                 1 
                               
                             
                           
                         
                       
                       
                         
                           
                             
                               y 
                                
                               
                                 
                                   ( 
                                   
                                     
                                       l 
                                       · 
                                       
                                         M 
                                         sc 
                                         PUCCH 
                                       
                                     
                                     + 
                                     
                                       i 
                                       · 
                                       P 
                                     
                                     + 
                                     p 
                                   
                                   ) 
                                 
                                 · 
                                 
                                    
                                   
                                     
                                       - 
                                       j 
                                     
                                      
                                     
                                       
                                         2 
                                          
                                         π 
                                          
                                         
                                             
                                         
                                          
                                         k 
                                       
                                       
                                         
                                           M 
                                           sc 
                                           PUCCH 
                                         
                                         / 
                                         P 
                                       
                                     
                                   
                                 
                               
                             
                             , 
                           
                         
                       
                     
                   
                   
                     
                       
                         if 
                          
                         
                             
                         
                          
                         
                           p 
                           ′ 
                         
                       
                       = 
                       p 
                     
                   
                 
                 
                   
                     
                       0 
                       , 
                     
                   
                   
                     
                       
                         if 
                          
                         
                             
                         
                          
                         
                           p 
                           ′ 
                         
                       
                       ≠ 
                       p 
                     
                   
                 
               
             
           
         
       
     
         [0061]    A slightly different mapping is 
         [0000]    
       
         
           
             
               
                 z 
                 
                   ( 
                   p 
                   ) 
                 
               
                
               
                 ( 
                 
                   
                     l 
                     · 
                     
                       M 
                       sc 
                       PUCCH 
                     
                   
                   + 
                   
                     ( 
                     
                       
                         k 
                         · 
                         P 
                       
                       + 
                       
                         
                           
                             ( 
                             
                               
                                 p 
                                 ′ 
                               
                               + 
                               
                                 l 
                                  
                                 
                                     
                                 
                                  
                                 mod 
                                  
                                 
                                     
                                 
                                  
                                 P 
                               
                             
                             ) 
                           
                           · 
                           
                             Δ 
                             f 
                           
                         
                          
                         mod 
                          
                         
                             
                         
                          
                         
                           M 
                           sc 
                           PUCCH 
                         
                       
                     
                     ) 
                   
                 
                 ) 
               
             
             = 
             
               { 
               
                 
                   
                     
                       
                         
                           
                             
                               1 
                               
                                 
                                   
                                     M 
                                     sc 
                                     PUCCH 
                                   
                                   / 
                                   P 
                                 
                               
                             
                              
                             
                               ∑ 
                               
                                 i 
                                 = 
                                 0 
                               
                               
                                 
                                   
                                     M 
                                     sc 
                                     PUCCH 
                                   
                                   / 
                                   P 
                                 
                                 - 
                                 1 
                               
                             
                           
                         
                       
                       
                         
                           
                             
                               y 
                                
                               
                                 
                                   ( 
                                   
                                     
                                       l 
                                       · 
                                       
                                         M 
                                         sc 
                                         PUCCH 
                                       
                                     
                                     + 
                                     
                                       i 
                                       · 
                                       P 
                                     
                                     + 
                                     p 
                                   
                                   ) 
                                 
                                 · 
                                 
                                    
                                   
                                     
                                       - 
                                       j 
                                     
                                      
                                     
                                       
                                         2 
                                          
                                         π 
                                          
                                         
                                             
                                         
                                          
                                         k 
                                       
                                       
                                         
                                           M 
                                           sc 
                                           PUCCH 
                                         
                                         / 
                                         P 
                                       
                                     
                                   
                                 
                               
                             
                             , 
                           
                         
                       
                     
                   
                   
                     
                       
                         if 
                          
                         
                             
                         
                          
                         
                           p 
                           ′ 
                         
                       
                       = 
                       p 
                     
                   
                 
                 
                   
                     
                       0 
                       , 
                     
                   
                   
                     
                       
                         if 
                          
                         
                             
                         
                          
                         
                           p 
                           ′ 
                         
                       
                       ≠ 
                       p 
                     
                   
                 
               
             
           
         
       
     
         [0000]    which leads to the same subcarrier mapping every P-th SC-FDMA symbol. 
         [0062]    Demodulation Reference Signal 
         [0063]    As shown in  FIG. 7 , because there are P transmit antennas, P different reference sequences may be used to generate the demodulation reference signals. In the example shown, P=2, thus two reference sequences are used: a first reference sequence (RS 1 ) and a second reference sequence (RS 2 ). RS 1  is transmitted using antenna port 0 and RS 2  is transmitted using antenna port 1. Each RS may be transmitted once or twice during a slot, depending on whether normal or extended cyclic prefix (CP) subframes are being used. In the example shown, normal CP subframes are being used. The same demodulation reference signal generation for Format 2 PUCCH is applied except the orthogonal sequences are given in table III, below: 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE III 
               
             
             
               
                   
               
               
                 Orthogonal sequences [  w (0) . . . 
               
               
                   w (N RS   PUCCH  − 1)] for DFT-S-OFDM PUCCH. 
               
             
          
           
               
                 Sequence index  n   oc (n s ) 
                 Normal cyclic prefix 
                 Extended cyclic prefix 
               
               
                   
               
               
                 0 
                 [+1 +1] 
                 [1] 
               
               
                 1 
                 [+1 −1] 
                 N/A 
               
               
                   
               
             
          
         
       
     
         [0064]    With N RS   PUCCH =2 and the standard setting of Δ shift   PUCCH =2 in normal CP subframes, there are 12 reference sequences available. The numbers of UEs that can be multiplexed on the same resource block are 5, 5, 4 and 3 for P=1, 2, 3 and 4, respectively. With N RS   PUCCH =1 and the standard setting of Δ shift   PUCCH =2 in extended CP subframes, there are 6 reference sequences available. The numbers of UEs that can be multiplexed on the same RB are 5, 3, 2 and 1 for P=1, 2, 3 and 4, respectively. 
         [0065]    RS 1  and RS 2  may be of length N SC   RB /P. Suitable sequences are CASAC sequences of length N SC   RB /P or computer-optimized sequences. From one base sequence additional orthogonal sequences can be derived by cyclic shifting the base sequence as described in 3GPP TS 36.211, “Physical Channel and Modulation.” For normal CP with N RS   PUCCH =2 RS per slot time-domain block spreading can be applied to increase the number of available RS sequences or alternatively to increase the cyclic shift distance between RS sequences 
         [0066]    RS 1  and RS 2  may be transmitted on the same set of subcarriers. In such embodiments, RS 1  and RS 2  may be orthogonal. For example, RS 1  may be a cyclic shift of the second reference sequence. 
         [0067]    In other embodiments, the reference sequences may be mapped in a distributed fashion, like the data payload as discussed above. That is, the RS of the different antenna ports are mapped to different frequency-domain combs. For example, for P=2 antennas: RS for antenna port 0 (e.g., RS 1 ) occupies the even-indexed sub-carriers in even-indexed SC-FDMA symbols and in odd-indexed sub-carriers in odd-indexed SC-FDMA symbols (or vice versa); and RS signal for antenna port 1 (e.g., RS 2 ) occupies the odd-indexed sub-carriers in even-indexed SC-FDMA symbols and in even-indexed sub-carriers in odd-indexed SC-FDMA symbols (or vice versa). 
         [0068]    Referring now to  FIG. 9 ,  FIG. 9  illustrates an alternative embodiment of the transmit diversity coding apparatus shown in  FIG. 7 . This alternative embodiment, apparatus  900 , is nearly identical with apparatus  700 , with the exception that, in apparatus  700  there is a single scrambler and symbol generator, whereas, in apparatus  900 , a scrambler  704  and a symbol generator (SG)  706  are placed in each branch corresponding to an SC-FDMA symbol. 
         [0069]    In apparatus  900 , the scrambling code can be made SC-FDMA symbol dependent by initializing each scrambler shown in  FIG. 9  at the beginning of each slot with a seed that depends on the slot or subframe number. 
         [0070]    Other ways to make the scrambling code SC-FDMA symbol dependent are possible. For example, for the first slot the bits {tilde over (b)}(0),{tilde over (b)}(1), . . . ,{tilde over (b)}(B/2−1) and for the second slot the bits {tilde over (b)}(B/2),{tilde over (b)}(B/2+1), . . . ,{tilde over (b)}(B−1) are repeated N SF,0   PUCCH  and N SF,1   PUCCH  times, respectively. The bits in the first and second slot are then scrambled by a B/2·N SF,0   PUCCH  and B/2·N SF,1   PUCCH  element long sequence, respectively. The scrambling sequence generator is initialized at the beginning of each slot with a seed that depends on the slot or subframe number. The scrambled bits are then mapped to QPSK symbols and in each SC-FDMA N SC   RB  QPSK symbols are transmitted. 
         [0071]    Alternatively, the bit block {tilde over (b)}(0),{tilde over (b)}(1), . . . ,{tilde over (b)}(B/2−1) is repeated N SF,0   PUCCH  times and concatenated with the bit block {tilde over (b)}(B/2).{tilde over (b)}(B/2+1), . . . . ,{tilde over (b)}(B−1) which is repeated N SF,1   PUCCH  times to form a B/2·(N SF,0   PUCCH +N SF,1   PUCCH ) element long bit block. This bit element long bit block. This bit sequence is then scrambled. The scrambling sequence generator is initialized at the beginning of each subframe with a seed that depends on the subframe number. The scrambled bits are then mapped to QPSK symbols and in each SC-FDMA N SC   RB  QPSK symbols are transmitted. 
         [0072]    Referring now to  FIG. 10 ,  FIG. 10  illustrates a block diagram of an example mobile terminal  102  in which transmit diversity coding apparatus  700  and/or transmit diversity coding apparatus  900  may be implemented. As shown in  FIG. 10 , terminal  102  may include: a data processor  1002 , which may include one or more microprocessors and/or one or more circuits, such as an application specific integrated circuit (ASIC), Field-programmable gate arrays (FPGAs), etc; a transmitter and a receiver  1004  coupled to antennas  111  and  112  via antenna port 0 (p0) and antenna port 1 (p1), respectively, for wireless communications; input/out devices  1021  (e.g., a display screen  1022 ); a storage system  1006 , which may include one or more non-volatile storage devices and/or one or more volatile storage devices (e.g., random access memory (RAM)). In embodiments where data processor  1002  includes a microprocessor, computer instructions  1008  (i.e., computer readable code means) may be stored in storage system  1006 . Configuration parameters  1010  may also be stored. The computer instructions  1008  may be embodied in a computer program stored using a computer readable means, such as, but not limited, to magnetic media (e.g., a hard disk), optical media (e.g., a DVD), memory devices (e.g., random access memory), etc. In some embodiments, computer instructions  1008  are configured such that when computer instructions  1008  are executed, computer instructions  1008  cause mobile terminal  102  to perform steps described above (e.g., steps describe above with reference to the flow charts shown in  FIGS. 2 and 6 ). In other embodiments, mobile terminal  102  is configured to perform steps described above without the need for computer instructions  1008 . That is, for example, data processor  1002  may consist merely of one or more ASICs. Hence, the features of the present invention described above may be implemented in hardware and/or software. For example, in particular embodiments, the functional components of apparatus  700  and/or apparatus  900  described above may be implemented in terminal  102  by processor  1002  executing computer instructions  1008 , by processor  1002  operating independent of any computer instructions  1008 , or by any suitable combination of hardware and/or software. 
         [0073]    While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 
         [0074]    Additionally, while the processes described above and illustrated in the drawings are shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, and some steps may be performed in parallel.